Normative Data for the 12-Item Sniffin' Sticks Odor Identification Test in Older Adults

OBJECTIVE

Quantitative olfactory assessment has demonstrated clinical utility for the evaluation of a range of neurologic, psychiatric, and sinonasal conditions. Here, we provide age, sex, race, and education-specific normative data for the 12-item Sniffin Sticks Odor Identification Test (SSOIT-12) in older Black and White U.S. adults without preclinical or clinical dementia or sinonasal disease.

METHOD

A sample of 2,224 Atherosclerosis Risk in Communities study participants aged 66-89 years were included. A normative regression equation was developed using a linear model for the association of age, sex, race, and education with odor identification score. Regression-based normative mean scores and percentiles were generated by age, sex, race, and education groups.

RESULTS

Participants (mean age = 74 years, 59% women, 20% Black, 48% > high school education) had a mean SSOIT-12 score of 9.8. Age, sex, race, and education were all associated with odor identification performance (all ps < .05). A linear regression model for the predicted SSOIT-12 score was developed for use with an individual's actual SSOIT-12 score in order to calculate the Z-score and corresponding percentile for a specific age, sex, race, and education group. Data are also reported in tabular format.

CONCLUSIONS

Our study provides SSOIT-12 normative data obtained from a large population of White and Black older adults without preclinical or clinical dementia or sinonasal disease living in the USA. These findings can aid clinicians in assessing the degree of olfactory loss, establishing concordance with a person's perception of olfactory difficulties and quantitatively monitoring changes in olfactory performance over time.

Differential Cognitive Effects of Unilateral Subthalamic Nucleus Deep Brain Stimulation for Parkinson's Disease

OBJECTIVE

The aim of this study was to investigate the cognitive effects of unilateral directional versus ring subthalamic nucleus deep brain stimulation (STN DBS) in patients with advanced Parkinson's disease.

METHODS

We examined 31 participants who underwent unilateral STN DBS (left n = 17; right n = 14) as part of an National Institutes of Health (NIH)-sponsored randomized, double-blind, crossover study contrasting directional versus ring stimulation. All participants received unilateral DBS implants in the hemisphere more severely affected by motor parkinsonism. Measures of cognition included verbal fluency, auditory-verbal memory, and response inhibition. We used mixed linear models to contrast the effects of directional versus ring stimulation and implant hemisphere on longitudinal cognitive function.

RESULTS

Crossover analyses showed no evidence for group-level changes in cognitive performance related to directional versus ring stimulation. Implant hemisphere, however, impacted cognition in several ways. Left STN participants had lower baseline verbal fluency than patients with right implants (t [20.66 = -2.50, p = 0.02]). Verbal fluency declined after left (p = 0.013) but increased after right STN DBS (p < 0.001), and response inhibition was faster following right STN DBS (p = 0.031). Regardless of hemisphere, delayed recall declined modestly over time versus baseline (p = 0.001), and immediate recall was unchanged.

INTERPRETATION

Directional versus ring STN DBS did not differentially affect cognition. Similar to prior bilateral DBS studies, unilateral left stimulation worsened verbal fluency performance. In contrast, unilateral right STN surgery increased performance on verbal fluency and response inhibition tasks. Our findings raise the hypothesis that unilateral right STN DBS in selected patients with predominant right brain motor parkinsonism could mitigate declines in verbal fluency associated with the bilateral intervention. ANN NEUROL 2024.

Impact of Acute Dopamine Replacement on Cognitive Function in Parkinson's Disease

BACKGROUND

PD causes striatal dopaminergic denervation in a posterior/dorsal to anterior/ventral gradient, leaving motor and associative cortico-striato-pallido-thalamic loops differentially susceptible to hyperdopaminergic effects with treatment. As the choice and titration of symptomatic PD medications are guided primarily by motor symptoms, it is important to understand their cognitive implications.

OBJECTIVE

To investigate the effects of acute dopaminergic medication administration on executive function in Parkinson's disease (PD).

METHODS

Participants with idiopathic PD were administered the oral Symbol Digit Modalities Test (SDMT; n = 181) and the Stroop test (n = 172) in the off-medication and "best on" medication states. ANCOVA was used to test for differences between off-medication and on-medication scores corrected for age and years of education.

RESULTS

After administration of symptomatic medications, scores worsened on the SDMT (F = 11.70, P < 0.001, d = -0.13), improved on the Stroop color (F = 26.89, P < 0.001, d = 0.184), word (F = 6.25, P = 0.013, d = 0.09), and color-word (F = 13.22, P < 0.001, d = 0.16) test components, and the Stroop difference and ratio-based interference scores did not significantly change. Longer disease duration correlated with lower scores on the SDMT, Stroop color, word, and color-word scores; however, longer disease duration and higher levodopa-equivalents correlated with higher Stroop difference-based interference scores.

CONCLUSIONS

Symptomatic medication differentially affects performance on two cognitive tests in PD. After acute treatment, core Stroop measures improved, Stroop interference was unchanged, and SDMT performance worsened, likely reflecting complex changes in processing speed and executive function related to acute treatment. When considering motor symptom therapies in PD, an individual's cognitive demands and expectations, especially regarding executive function, should be considered.

Physical Function Trajectories and Mortality in Older Adults With Multisensory Impairment

Importance

Single sensory impairment is associated with reduced functional resilience and increased mortality, though the effects of multiple sensory deficits are not known.

Objective

To investigate longitudinal associations of the type, severity, and number of sensory impairments with physical function trajectories and mortality in older adults.

Design, Setting, and Participants

This retrospective analysis of a longitudinal cohort study, the Health, Aging, and Body Composition (Health ABC) study, incorporated data from April 1997 to July 2013, featuring a 16-year follow-up with annual examinations and questionnaires. The cohort comprised 3075 men and women, aged 70 to 79 years at baseline, residing in Memphis, Tennessee, and Pittsburgh, Pennsylvania. All participants with complete sensory testing and covariate data at analytical baseline (year 5, 2002) were included. The data were analyzed September 1, 2022.

Exposures

Visual, olfactory, auditory, and touch sensory functions were assessed between 2000 and 2002.

Main Outcomes

The main outcomes included physical functioning trajectories and mortality risk. Physical function was assessed longitudinally using the Health ABC physical performance battery (HABCPPB).

Results

A total of 1825 individuals (mean [SD] age, 77.4 [3.2] years; 957 [52%] female) were included in this study. Multivariable analysis of HABCPPB decline indicated that having 1 sensory impairment (β estimate, -0.01 [95% CI, -0.02 to -0.001]); 2 sensory impairments (β estimate, -0.01 [95% CI, -0.02 to -0.01]); 3 sensory impairments (β estimate, -0.03 [95% CI, -0.04 to -0.02]); or 4 sensory impairments (β estimate, -0.04 [95% CI, -0.05,-0.03]) was significantly associated with a steeper HABCPPB score decline in a dose-dependent manner. Adjusted Cox proportional hazards models indicated that having 1 sensory impairment (hazard ratio [HR], 1.35 [95% CI, 1.01-1.81]), 2 sensory impairments (HR, 1.58 [95% CI, 1.19-2.11]), 3 sensory impairments (HR, 1.79 [95% CI, 1.33-2.42]), or 4 sensory impairments (HR, 1.97 [95% CI, 1.39-2.79]) was significantly associated with increased mortality risk in a similarly dose-dependent manner.

Conclusion

In this retrospective cohort study, the degree and number of multiple sensory impairments were associated with worse physical functioning and increased mortality risk. These findings represent an opportunity for further investigation into the value of screening, prevention, and treatment of sensory impairments to reduce morbidity and mortality in older adults.

Does Olfactory Training Improve Brain Function and Cognition? A Systematic Review

Olfactory training (OT), or smell training,consists of repeated exposure to odorants over time with the intended neuroplastic effect of improving or remediating olfactory functioning. Declines in olfaction parallel declines in cognition in various pathological conditions and aging. Research suggests a dynamic neural connection exists between olfaction and cognition. Thus, if OT can improve olfaction, could OT also improve cognition and support brain function? To answer this question, we conducted a systematic review of the literature to determine whether there is evidence that OT translates to improved cognition or altered brain morphology and connectivity that supports cognition. Across three databases (MEDLINE, Scopus, & Embase), 18 articles were identified in this systematic review. Overall, the reviewed studies provided emerging evidence that OT is associated with improved global cognition, and in particular, verbal fluency and verbal learning/memory. OT is also associated with increases in the volume/size of olfactory-related brain regions, including the olfactory bulb and hippocampus, and altered functional connectivity. Interestingly, these positive effects were not limited to patients with smell loss (i.e., hyposmia & anosmia) but normosmic (i.e., normal ability to smell) participants benefitted as well. Implications for practice and research are provided.

Inflammation-related pathology in the olfactory epithelium: its impact on the olfactory system in psychotic disorders

Smell deficits and neurobiological changes in the olfactory bulb (OB) and olfactory epithelium (OE) have been observed in schizophrenia and related disorders. The OE is the most peripheral olfactory system located outside the cranium, and is connected with the brain via direct neuronal projections to the OB. Nevertheless, it is unknown whether and how a disturbance of the OE affects the OB in schizophrenia and related disorders. Addressing this gap would be the first step in studying the impact of OE pathology in the disease pathophysiology in the brain. In this cross-species study, we observed that chronic, local OE inflammation with a set of upregulated genes in an inducible olfactory inflammation (IOI) mouse model led to a volume reduction, layer structure changes, and alterations of neuron functionality in the OB. Furthermore, IOI model also displayed behavioral deficits relevant to negative symptoms (avolition) in parallel to smell deficits. In first episode psychosis (FEP) patients, we observed a significant alteration in immune/inflammation-related molecular signatures in olfactory neuronal cells (ONCs) enriched from biopsied OE and a significant reduction in the OB volume, compared with those of healthy controls (HC). The increased expression of immune/inflammation-related molecules in ONCs was significantly correlated to the OB volume reduction in FEP patients, but no correlation was found in HCs. Moreover, the increased expression of human orthologues of the IOI genes in ONCs was significantly correlated with the OB volume reduction in FEP, but not in HCs. Together, our study implies a potential mechanism of the OE-OB pathology in patients with psychotic disorders (schizophrenia and related disorders). We hope that this mechanism may have a cross-disease implication, including COVID-19-elicited mental conditions that include smell deficits.

Poor olfaction prior to cardiac surgery: Association with cognition, plasma neurofilament light, and post-operative delirium

OBJECTIVES

Post-operative delirium (POD) affects up to 50% of cardiac surgery patients, with higher incidence in older adults. There is increasing need for screening tools that identify individuals most vulnerable to POD. Here, we examined the relationship between pre-operative olfaction and both incident POD and POD severity in patients undergoing cardiac surgery. We also examined cross-sectional relationships between baseline olfaction, cognition, and plasma neurofilament light (NfL).

METHODS

Individuals undergoing cardiac surgery (n = 189; mean age = 70 years; 75% men) were enrolled in a clinical trial of cerebral autoregulation monitoring. At baseline, odor identification performance (Brief Smell Identification Test), cognitive performance, and plasma concentrations of NfL levels (Simoa™ NF-Light Assay) were measured. Delirium was assessed with the Confusion Assessment Method (CAM) or CAM-ICU, and delirium severity was assessed using the Delirium Rating Scale-Revised-98. The association of baseline olfaction, delirium incidence, and delirium severity was examined in regression models adjusting for age, duration of cardiopulmonary bypass, logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE), and baseline cognition.

RESULTS

Olfactory dysfunction was present in 30% of patients, and POD incidence was 44%. Pre-operative olfactory dysfunction was associated with both incident POD (OR = 3.17, p = 0.001) and greater severity of POD after cardiac surgery (OR = 3.94 p < 0.001) in models adjusted for age, duration of bypass, and a surgical risk score. The addition of baseline cognition attenuated the strength of the association, but it remained significant for incident POD (OR = 2.25, p = 0.04) and POD severity (OR 2.10, p = 0.04). Poor baseline olfaction was associated with greater baseline cognitive dysfunction (p < 0.001) and increased baseline plasma NfL concentrations (p = 0.04). Neither age, cognition, nor baseline NFL concentration modified the association of impaired olfaction and delirium outcomes.

CONCLUSIONS

Olfactory assessment may be a useful pre-surgical screening tool for the identification of patients undergoing cardiac surgery at increased risk of POD. Identifying those at highest risk for severe delirium and poor cognitive outcomes following surgery would allow for earlier intervention and pre-operative rehabilitation strategies, which could ultimately impact the functional disability and morbidity associated with POD.

Inflammation-related pathology in the olfactory epithelium: its impact on the olfactory system in psychotic disorders

Smell deficits and neurobiological changes in the olfactory bulb (OB) and olfactory epithelium (OE) have been observed in schizophrenia and related disorders. The OE is the most peripheral olfactory system located outside the cranium, and is connected with the brain via direct neuronal projections to the OB. Nevertheless, it is unknown whether and how a disturbance of the OE affects the OB in schizophrenia and related disorders. Addressing this gap would be the first step in studying the impact of OE pathology in the disease pathophysiology in the brain. In this cross-species study, we observed that chronic, local OE inflammation with a set of upregulated genes in an inducible olfactory inflammation (IOI) mouse model led to a volume reduction, layer structure changes, and alterations of neuron functionality in the OB. Furthermore, IOI model also displayed behavioral deficits relevant to negative symptoms (avolition) in parallel to smell deficits. In first episode psychosis (FEP) patients, we observed a significant alteration in immune/inflammation-related molecular signatures in olfactory neuronal cells (ONCs) enriched from biopsied OE and a significant reduction in the OB volume, compared with those of healthy controls (HC). The increased expression of immune/inflammation-related molecules in ONCs was significantly correlated to the OB volume reduction in FEP patients, but no correlation was found in HCs. Moreover, the increased expression of human orthologues of the IOI genes in ONCs was significantly correlated with the OB volume reduction in FEP, but not in HCs. Together, our study implies a potential mechanism of the OE-OB pathology in patients with psychotic disorders (schizophrenia and related disorders). We hope that this mechanism may have a cross-disease implication, including COVID-19-elicited mental conditions that include smell deficits.

Olfactory Dysfunction and Depression Trajectories in Community-Dwelling Older Adults

BACKGROUND

We examined the relationship between baseline olfactory performance and incident significant depressive symptoms and longitudinal depression trajectories in well-functioning older adults. Inflammation and cognitive status were examined as potential mediators.

METHODS

Older adults (n = 2 125, 71-82 years, 51% female, 37% Black) completed an odor identification task at Year 3 (our study baseline) of the Health, Aging, and Body Composition study. Cognitive assessments, depressive symptoms, and inflammatory markers were ascertained across multiple visits over 8 years. Discrete-time complementary log-log models, group-based trajectory models, and multivariable-adjusted multinomial logistic regression were employed to assess the relationship between baseline olfaction and incident depression and longitudinal depression trajectories. Mediation analysis assessed the influence of cognitive status on these relationships.

RESULTS

Individuals with lower olfaction had an increased risk of developing significant depressive symptoms at follow-up (hazard ratio = 1.04, 95% confidence interval [CI]: 1.00, 1.08). Of the 3 patterns of longitudinal depression scores identified (stable low, stable moderate, and stable high), poorer olfaction was associated with a 6% higher risk of membership in the stable moderate (relative risk ratio [RRR] = 1.06, 95% CI: 1.02, 1.10)/stable high (RRR = 1.06, 95% CI: 1.00, 1.12) groups, compared to the stable low group. Poor cognitive status, but not inflammation, partially mediated the relationship between olfactory performance and incident depression symptom severity.

CONCLUSIONS

Suboptimal olfaction could serve as a prognostic indicator of vulnerability for the development of late-life depression. These findings underscore the need for a greater understanding of olfaction in late-life depression and the demographic, cognitive, and biological factors that influence these relationships over time.

Reduction in olfactory dysfunction prevalence among patients with diabetes taking metformin

KEY POINTS

Metformin treatment is associated with reduced olfactory dysfunction (OD) in diabetic patients Metformin may possess potential protective effects on olfaction beyond glycemic control.

Olfactory Dysfunction Following Moderate to Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVE

Reports of smell loss following traumatic brain injury (TBI) are a well-documented but understudied phenomenon. Given the broad consequences of olfactory loss, we characterized psychophysical olfactory dysfunction in individuals with moderate to severe TBI using systematic review and meta-analytic methods.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) protocol, five databases (PubMed, EMBASE, Cochrane Library, Web of Science, Scopus) were reviewed for studies investigating olfactory dysfunction in persons with moderate to severe TBI. Of the 5,223 studies reviewed, 19 met our inclusion criteria for the systematic review and 11 met inclusion criteria for meta-analysis. We calculated effect sizes (Hedges' g) to characterize the degree of olfactory dysfunction between patients with moderate to severe TBI and controls.

RESULTS

A total of 951 moderate-severe TBI patients from 19 studies were included in the systematic review, which largely demonstrated poorer olfactory psychophysical performances in this patient population. Meta-analysis demonstrated a large effect size for olfactory dysfunction in moderate-severe TBI relative to healthy controls (g=-2.43, 95%CI: -3.16 < δ<-1.69). The magnitude of the effect was moderated by age and patient sex, with larger effect sizes associated with older age (following exclusion of a pediatric population) and larger compositions of women in the patient group.

CONCLUSION

Moderate to severe TBI is associated with prominent olfactory dysfunction. Significant research gaps remain regarding the mechanism, recovery and natural history of olfactory dysfunction following moderate to severe TBI, which has significant clinical implications for the identification and treatment for those with post-traumatic olfactory dysfunction.

Gaps in clinical research in frontotemporal dementia: A call for diversity and disparities-focused research

Frontotemporal dementia (FTD) is one of the leading causes of dementia before age 65 and often manifests as abnormal behavior (in behavioral variant FTD) or language impairment (in primary progressive aphasia). FTD's exact clinical presentation varies by culture, language, education, social norms, and other socioeconomic factors; current research and clinical practice, however, is mainly based on studies conducted in North America and Western Europe. Changes in diagnostic criteria and procedures as well as new or adapted cognitive tests are likely needed to take into consideration global diversity. This perspective paper by two professional interest areas of the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment examines how increasing global diversity impacts the clinical presentation, screening, assessment, and diagnosis of FTD and its treatment and care. It subsequently provides recommendations to address immediate needs to advance global FTD research and clinical practice.

A - 44 Social Cognition and its Neuroanatomic Correlates in Frontotemporal Dementia

OBJECTIVE

Frontotemporal dementia (FTD) often presents with impaired social cognition in both the behavioral and language variants. Establishing reliable measures and neural correlates of social cognition may aid in staging and monitoring FTD subtypes. Here, we examined group differences in social cognitive measures between FTD subtypes and cortical thickness correlates of social cognition across groups.

METHOD

Participants with behavioral variant FTD (n = 53; bvFTD), semantic variant primary progressive aphasia (n = 32; svPPA) and non-fluent variant PPA (n = 32; nfPPA) were enrolled in the Frontotemporal Lobar Degeneration Neuroimaging Initiative (NIFD). In first-visit data, we examined group differences in social cognition measures [Interpersonal Reactivity Index (IRI), Revised Social-Monitoring Scale (RSMS), and Behavioral Inhibition/Activation (BIS/BAS) Scales]. We used multivariate regression adjusted for age, total intracranial volume, and CDR global score to explore associations between social cognition and cortical thickness in pre-specified regions.

RESULTS

Reduced perspective-taking and sensitivity to socio-emotional expressiveness was observed in early-stage bvFTD and svPPA groups compared to the nfPPA group. Across FTD cohorts, increased perspective-taking was associated with reduced cortical thickness of regions within the salience and default mode networks. Increased empathic concern was associated with increased left inferior parietal cortical thickness. Increased behavioral inhibition was associated with reduced right posterior cingulate cortical thickness. Increased behavioral activation was associated with reduced right pars triangularis cortical thickness.

CONCLUSIONS

Social cognition is affected in early-stage bvFTD and svPPA to a greater extent than nfPPA. Neural correlates of social cognition are varied and warrant additional study as our findings contrast with previous literature that has typically linked lower perspective-taking with atrophy.

A - 11 Cognitive and Clinical Correlates of Olfactory Function in Adults with Epilepsy

OBJECTIVE

Olfactory dysfunction is well-documented in epilepsy. We recently found that olfactory assessment may have clinical utility in identifying surgical candidates with intractable epilepsy who benefit from magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT). However, the demographic, clinical, and cognitive correlates of olfaction in epilepsy remain unclear and could aid in understanding its potential utility in clinical examinations.

METHOD

We identified 60 outpatients with epilepsy (mean age = 38.22 ± 13.84 years; 50% male; 89.3% right-handed; seizure location: 45.0% left, 33.3% right, 13.3% bilateral, 8.3% unspecified) referred for neuropsychological evaluation in the Johns Hopkins Division of Medical Psychology Clinic. Neuropsychological evaluation included the 16-item Sniffin' Sticks Odor Identification Test. Linear regression models were used to examine associations between 1) olfaction and demographic/clinical characteristics (age, sex, education, duration of illness, seizure laterality) and 2) olfaction and cognition (processing speed, language, auditory-verbal and visuospatial memory, executive functioning; adjusted for demographic/clinical characteristics).

RESULTS

Olfactory performance was not significantly associated with demographic or clinical characteristics. Across all participants, better olfactory performance was associated with better auditory-verbal memory (B = 5.04, t(46) = 4.16, p < 0.001) and visual confrontation naming (B = 1.53, t(45) = 4.11, p < 0.001) with correction for multiple comparisons. In a subset with lateralizing epilepsy (n = 47), better odor identification performance remained a significant predictor of the aforementioned cognitive measures with adjustment for demographic and clinical characteristics.

CONCLUSIONS

Consistent with work in other neurologic conditions, our preliminary findings indicate that olfactory function is associated with verbally-mediated neuropsychological measures in epilepsy. Future studies utilizing pre-surgical neuroimaging will examine the association between olfaction, cognition, and radiographic markers of tissue integrity in epilepsy.

A - 9 The Progressive Supranuclear Palsy Rating Scale Identifies Early Motor Symptoms in Primary Progressive Aphasia

OBJECTIVE

This study examined cross-sectional differences in Progressive Supranuclear Palsy Rating Scale (PSPRS) scores among participants with behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA). We hypothesized that participants with nonfluent/agrammatic PPA (nfPPA) will show the highest (worst) PSPRS scores and greater gray matter atrophy in regions associated with progressive supranuclear palsy (PSP) pathology.

METHOD

Participants were enrolled in the ARTFL LEFFTDS Longitudinal Frontotemporal Lobar Degeneration consortium (ALLFTD). Analyses were limited to first visit data. Ten anatomic regions of interest were pre-selected for analysis based on previously identified neuroanatomic correlates of PSPRS performance. Differences in participant characteristics and clinical outcomes were compared using pairwise comparison of means. Linear multivariable regression adjusting for age and total intracranial volume was used to examine associations between regional gray matter volumes and diagnosis. The analyses were stratified by disease severity.

RESULTS

Participants with early-stage nfPPA had higher total PSPRS scores compared to those with bvFTD or semantic dementia (SD) and performed more poorly on domains of dysphagia, fine motor movements, falls, postural stability, dysarthria, saccadic eye movements, and motor rigidity. Participants with advanced-stage nfPPA showed greater atrophy in the left putamen, supplementary motor area, and precentral gyrus than those with bvFTD.

CONCLUSION

Our study highlights the phenotypic complexity of PPA and the utility of the PSPRS in capturing early motor symptoms in nfPPA. These data suggest that the PSPRS may facilitate early intervention in identifying and facilitating treatment of early motor symptoms, decreasing disability and improving quality of life in PPA.

B - 92 Poor Olfaction Prior to Cardiac Surgery: Associations with Cognition, Plasma Neurofilament Light and Postoperative Delirium in a Prospective Nested Cohort Study

OBJECTIVE

This study examined the association between pre-operative olfactory performance and delirium after cardiac surgery. As a secondary aim, we examined the relationship between baseline olfaction, cognitive functioning, and plasma neurofilament light (NfL).

METHOD

Individuals undergoing cardiac surgery were recruited as part of a clinical trial in which blood pressure during bypass was targeted using cerebral autoregulation monitoring. There were 189 participants (mean age = 70 years; 75% men). At baseline, olfaction, cognition, and plasma concentrations of NfL were assessed using the 12-item Brief Smell Identification Test (BSIT), a battery of neuropsychological tests, and the Simoa™ NF-Light Assay, respectively. Impaired olfaction was defined as a score of ≤8 for men and ≤ 9 for women. Delirium was assessed using the Confusion Assessment Method (CAM) and CAM-ICU, and delirium severity was assessed using the Delirium Rating Scale-Revised-1998 (DRS-R-98). The association of baseline olfaction and delirium and delirium severity was examined in regression models adjusting for age, duration of bypass, a surgery risk score, and baseline cognitive performance.

RESULTS

In adjusted models, impaired olfaction at baseline was associated with both incident delirium (OR = 2.25, p = 0.04) and greater delirium severity (OR = 2.10, p = 0.04) after cardiac surgery. Furthermore, worse baseline olfaction was associated with impaired cognition (p < 0.001) and increased perioperative concentrations of plasma NfL (p = 0.04).

CONCLUSIONS

Pre-operative olfactory testing may provide insight into brain vulnerability, cognitive dysfunction, and delirium risk in individuals undergoing cardiac surgery. Psychophysical olfactory assessment may inform strategies for patient risk stratification and early identification of individuals at risk for post-operative delirium, allowing for delirium-prevention strategies.

A - 83 Associations between Subjective and Objective Cognition, Depression, and Quality of Life in Men Living with HIV

OBJECTIVE

In people living with HIV, subjective cognitive dysfunction is widely reported; however, few studies have examined the relationship between subjective cognitive functioning and performance-based measures of cognitive functioning, mood, and quality of life (QoL).

METHODS

Men living with HIV (MLWH) (n = 51, mean age = 54 years, 67% Black) completed measures of subjective cognitive functioning (Cognitive Failures Questionnaire; CFQ), objective cognitive performance (HVLT-R, TMT, UFOV, WRAT-3 Reading), health-related QoL (Medical Outcomes Short-Form; SF-36), mood (CES-D), and overall QoL (Control, Autonomy, Self-Realization, and Pleasure Quality of Life Scale; CASP-19). Pearson and Spearman correlation analyses were conducted to examine significant associations between variables. Alpha was set at 0.01 for all analyses.

RESULTS

The CFQ was not significantly correlated with performance on objective cognitive tests. However, significant associations were found between the CFQ and self-reported depression severity (CES-D; r = 0.655, p < 0.001), quality of life (CASP-19; r = -0.642, p < 0.001), and multiple subscales of the SF-36 (all p's < 0.003). Of note, correlations between the CFQ with SF-36 scales and CASP-19 were no longer significant after controlling for depressive symptoms.

CONCLUSIONS

Consistent with prior work, we found that subjective cognitive functioning may inadequately capture the full range of a person's cognitive functioning status. We extend these findings to a sample of MLWH and further clarify the possible influence that depressive symptoms have on subjective cognitive functioning and self-reported QoL measures. Future studies with larger samples and a more comprehensive neuropsychological battery will be helpful in understanding the full nature of these relationships.

A - 63 Neuropsychiatric and Cognitive Correlates of Pareidolias in Dementia with Lewy Bodies

OBJECTIVE

Pareidolias represent visual illusions of meaningful objects in ambiguous stimuli. Prior research has demonstrated phenomenological similarities between pareidolias and visual hallucinations (VH) and the potential clinical utility of pareidolias in discriminating dementia with Lewy bodies (DLB) from Alzheimer's dementia (ad). Though pareidolias have been linked with VH severity in DLB, the relationships between pareidolias and other neuropsychiatric symptoms have not been explored in large DLB samples.

METHOD

Individuals meeting 2017 McKeith criteria for probable DLB (n = 114) were enrolled in a multi-site systematic longitudinal study of the US DLB Consortium. Study assessments included an informant-rated psychiatric inventory (NPI), Montreal Cognitive Assessment (MoCA), and Noise Pareidolia Task (NPT). Ninety-five participants completed all clinical assessments. To examine baseline relationships between pareidolias responses (NPT) and the presence of 12 neuropsychiatric symptom dimensions (NPI), we used Poisson regression models with robust standard error estimates adjusted for age, education, disease duration, cognition (MoCA), and cholinesterase inhibitor use.

RESULTS

Contrary to expectation, the presence of VH was not associated with pareidolias in DLB (Incidence Rate Ratio = 1.37, p = 0.275). The presence of both delusions (IRR = 2.11, p = 0.01) and depression (IRR = 1.79, p = 0.015) was associated with greater pareidolias. Additionally, overall cognitive dysfunction was associated with pareidolias (IRR = 0.90, p < 0.001).

CONCLUSIONS

Our findings indicate that pareidolias are associated with poorer cognition and neuropsychiatric dimensions beyond VH, including depression and delusions. As pareidolias have been put forth as a surrogate marker of VH in DLB, future studies examining pareidolias in conjunction with comprehensive psychiatric/cognitive assessment and neuroimaging will further elucidate the clinical utility of pareidolia testing.

Association of Olfaction and Microstructural Integrity of Brain Tissue in Community-Dwelling Adults: Atherosclerosis Risk in Communities Neurocognitive Study

BACKGROUND AND OBJECTIVES

Research on olfaction and brain neuropathology may help understand brain regions associated with normal olfaction and dementia pathophysiology. To identify early regional brain structures affected in poor olfaction, we examined cross-sectional associations of microstructural integrity of the brain with olfaction in the Atherosclerosis Risk in Communities Neurocognitive Study.

METHODS

Participants were selected from a prospective cohort study of community-dwelling adults; selection criteria included the following: evidence of cognitive impairment, participation in a previous MRI study, and a random sample of cognitively normal participants. Microstructural integrity was measured by 2 diffusion tensor imaging (DTI) measures, fractional anisotropy (FA) and mean diffusivity (MD), and olfaction by a 12-item odor identification test at the same visit. Higher FA and MD values indicate better and worse microstructural integrity, respectively, and higher odor identification scores indicate better olfaction. We used brain region-specific linear regression models to examine associations between DTI measures and olfaction, adjusting for potential confounders.

RESULTS

Among 1,418 participants (mean age 76 ± 5 years, 41% male, 21% Black race, 59% with normal cognition), the mean olfaction score was 9 ± 2.3. Relevant to olfaction, higher MD in the medial temporal lobe (MTL) regions, namely the hippocampus (β -0.79 [95% CI -0.94 to -0.65] units lower olfaction score per 1 SD higher MD), amygdala, entorhinal area, and some white matter (WM) tracts connecting to these regions, was associated with olfaction. We also observed associations with MD and WM FA in multiple atlas regions that were not previously implicated in olfaction. The associations between MD and olfaction were particularly stronger in the MTL regions among individuals with mild cognitive impairment (MCI) compared with those with normal cognition (e.g., βhippocampus -0.75 [95% CI -1.02 to -0.49] and -0.44 [95% CI -0.63 to -0.26] for MCI and normal cognition, respectively, p interaction = 0.004).

DISCUSSION

Neuronal microstructural integrity in multiple brain regions, particularly the MTL (the regions known to be affected in early Alzheimer disease), is associated with odor identification ability. Differential associations in the MTL regions among cognitively normal individuals compared with those with MCI may reflect the earlier vs later effects of the dementia pathogenesis. It is likely that some of the associated regions may not have any functional relevance to olfaction.

Potential Role for Diet in Mediating the Association of Olfactory Dysfunction and Cognitive Decline: A Nationally Representative Study

In the context of a growing body of evidence associating olfactory dysfunction (OD) with cognitive decline, this cross-sectional study used data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) sample in order to explore the role of dietary intake in this association. Leveraging a nationally representative sample of U.S. adults aged 60 years and older, this study analyzed dietary patterns using exploratory factor analysis. OD was categorized based on the NHANES Pocket Smell Test, and cognitive function was measured with a battery of tests. Survey-weighted multivariable regressions and causal mediation analysis were used to examine the relationship between dietary patterns, OD, and cognitive function. Results indicated that a poor adherence to a diet rich in monounsaturated fats (MUFAs) and polyunsaturated fats (PUFAs) was independently associated with both cognitive and olfactory dysfunctions, after adjusting for sociodemographic and health factors. Moreover, the relationship between OD and cognitive decline was found to be partly mediated by adherence to such a diet. This study proposes a potential link between diet, olfactory function, and cognitive decline, highlighting the role of nutritional interventions in mitigating cognitive decline, particularly in individuals with olfactory impairment.

Factors Associated with Poor Olfaction and Olfactory Decline in Older Adults in the ARIC Neurocognitive Study

Olfactory function has significant implications for human health, but few risk factors for olfactory decline have been identified. We examined the factors associated with olfactory status and decline over five years in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. A 12-item odor identification test was used to assess olfaction in 6053 participants in 2011-2013 (ARIC visit 5, mean age: 75.6, 41% male, 23% Black race) and in 3235 participants in 2016-2017 (visit 6). We used Poisson regression models to examine cross-sectional associations of a range of potential factors with the total odor identification errors (mean errors: 2.8 ± 2.4) in visit 5 participants. We used mixed-effect Poisson regression to examine associations with olfactory decline between visits 5 and 6. We also examined associations with visit 5 anosmia prevalence (847 cases, 14%) and incident anosmia between the two visits (510 cases, 16%) using Poisson models. Older age, male sex, lower education, Black race, APOE ε4 alleles, and diabetes were associated with higher odor identification errors and higher anosmia prevalence, and greater physical activity and hypertension with better olfaction. Age, male sex, lower education, Black race, APOE ε4 allele, and vitamin B12 levels were associated with incident anosmia over 5 years. Older age was associated with faster olfactory decline. Future studies with longer follow-ups are warranted.

Weight Change and Neuropsychiatric Symptoms in Alzheimer's Disease and Frontotemporal Dementia: Associations with Cognitive Decline

Weight changes, neuropsychiatric symptoms (NPS), and cognitive decline often coincide in Alzheimer's disease (AD) and frontotemporal dementia (FTD); however, the direction of their relationship remains unclear. This study aims to clarify the connection between weight changes, NPS, and cognition in AD and FTD. We found that cognitive decline was associated with decreased body mass index (BMI) in AD, while BMI gain was associated with increased conversion to FTD. Elevated NPS were associated with decreased BMI in AD and increased BMI in FTD. Identifying early changes in NPS and BMI may facilitate the detection of cognitive decline, providing an opportunity for early intervention.

Differential cognitive effects of unilateral left and right subthalamic nucleus deep brain stimulation for Parkinson disease

Objective

To investigate hemispheric effects of directional versus ring subthalamic nucleus (STN) deep brain stimulation (DBS) surgery on cognitive function in patients with advanced Parkinson's disease (PD).

Methods

We examined 31 PD patients (Left STN n = 17; Right STN n = 14) who underwent unilateral subthalamic nucleus (STN) DBS as part of a NIH-sponsored randomized, cross-over, double-blind (ring vs directional) clinical trial. Outcome measures were tests of verbal fluency, auditory-verbal memory, and response inhibition. First, all participants were pooled together to study the effects of directional versus ring stimulation. Then, we stratified the groups by surgery hemisphere and studied the longitudinal changes in cognition post-unilateral STN DBS.

Results

Relative to pre-DBS cognitive baseline performances, there were no group changes in cognition following unilateral DBS for either directional or ring stimulation. However, assessment of unilateral DBS by hemisphere revealed a different pattern. The left STN DBS group had lower verbal fluency than the right STN group (t(20.66 = -2.50, p = 0.02). Over a period of eight months post-DBS, verbal fluency declined in the left STN DBS group (p = 0.013) and improved in the right STN DBS group over time (p < .001). Similarly, response inhibition improved following right STN DBS (p = 0.031). Immediate recall did not significantly differ over time, nor was it affected by implant hemisphere, but delayed recall equivalently declined over time for both left and right STN DBS groups (left STN DBS p = 0.001, right STN DBS differ from left STN DBS p = 0.794).

Conclusions

Directional and ring DBS did not differentially or adversely affect cognition over time. Regarding hemisphere effects, verbal fluency decline was observed in those who received left STN DBS, along with the left and right STN DBS declines in delayed memory. The left STN DBS verbal fluency decrement is consistent with prior bilateral DBS research, likely reflecting disruption of the basal-ganglia-thalamocortical network connecting STN and inferior frontal gyrus. Interestingly, we found an improvement in verbal fluency and response inhibition following right STN DBS. It is possible that unilateral STN DBS, particularly in the right hemisphere, may mitigate cognitive decline.

The relationship between weight loss and cognitive function in bariatric surgery

BACKGROUND

Previously, we reported short-term improvements in auditory attention, oromotor processing speed, and executive function during the active weight loss phase following bariatric surgery that persisted out to 3 months. In this study, our aims were to investigate the relationship between weight loss and cognitive performance in these patients 1 year following vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) surgery and to determine whether preoperative cognitive performance predicted weight loss.

METHODS

Adult women ages 18-55 approved for bariatric surgery completed a cognitive battery prior to and at 2, 12, 24, and 52 weeks following VSG (N = 17) or RYGB (N = 18). Scores from each task were assigned to one of the following cognitive domains: auditory attention, processing speed, memory, and executive functioning. Weight loss and cognitive scores for each domain were calculated and compared between cohorts.

RESULTS

RYGB surgery resulted in greater weight loss at 1-year follow-up relative to VSG. Both VSG and RYGB procedures resulted in improved performance on different measures of auditory attention and both surgery groups improved across all processing speed tasks. Within the executive function domain, both groups showed improvements, but only the RYGB procedure resulted in improved performance in the Trail Making Test. Baseline auditory attention and memory performance predicted weight loss at 1 year following RYGB but not VSG surgery. Controlling for baseline cognitive performance, percent total weight loss predicted auditory attention at 1 year following RYGB but not VSG surgery.

CONCLUSIONS

Bariatric surgery type may result in selective improvements in cognition during the first year following surgery. Presurgical cognitive performance as well as surgery type appears to influence weight loss outcomes.

Brain regions associated with olfactory dysfunction in first episode psychosis patients

OBJECTIVES

Olfactory dysfunction is reproducibly reported in psychotic disorders, particularly in association with negative symptoms. The superior frontal gyrus (SFG) has been frequently studied in patients with psychotic disorders, in particular with their associations with negative symptoms. The relationship between olfactory functions and brain structure has been studied in healthy controls (HCs). Nevertheless, the studies with patients with psychotic disorders are limited. Here we report the olfactory-brain relationship in a first episode psychosis (FEP) cohort through both hypothesis-driven (centred on the SFG) and data-driven approaches.

METHODS

Using data from 88 HCs and 76 FEP patients, we evaluated the correlation between olfactory functions and structural/resting-state functional magnetic resonance imaging (MRI) data.

RESULTS

We found a significant correlation between the left SFG volume and odour discrimination in FEP patients, but not in HCs. We also observed a significant correlation between rs-fMRI connectivity involving the left SFG and odour discrimination in FEP patients, but not in HCs. The data-driven approach didn't observe any significant correlations, possibly due to insufficient statistical power.

CONCLUSION

The left SFG may be a promising brain region in the context of olfactory dysfunction and negative symptoms in FEP.

Investigating relationships between post-prandial gut hormone responses and taste liking ratings prior to and following bariatric surgery: a pilot study

BACKGROUND

Alterations in gut hormone secretion and reported changes in taste preferences have been suggested to contribute to the weight-reducing effects of bariatric surgery. However, a link between changes in gut hormone secretion and taste preferences following bariatric surgery has yet to be elucidated.

METHODS

Here we examined the potential relationships between gut hormone responses (GLP-1 and PYY3-36 peak, ghrelin trough) to a test meal of Ensure and liking ratings for taste mixtures varying in sugar and fat content before and following bariatric surgery (vertical sleeve gastrectomy (VSG): N = 4; Roux-en Y gastric bypass (RYGB): N = 8).

RESULTS

Significant increases in GLP-1 and PYY3-36 peak and a significant drop in ghrelin trough were observed following surgery. Pre- and postoperation, patients with higher postprandial GLP-1 or PYY3-36 peaks gave lower liking ratings for mixtures containing a combination of fat and sugar (half and half + 20% added sugar) whereas, for the combined surgery analyses, no relationships were found with solutions comprised of high fat (half and half + 0% sugar), predominantly high sugar (skim milk + 20% added sugar), or low fat and low sugar (skim milk + 0% added sugar). Within the RYGB patients, patients with the greatest increase in postprandial GLP-1 peak from preoperation to postoperation also demonstrated the greatest decrease in liking for half & half + 20% added sugar and skim milk + 20% added sugar, but not the unsweetened version of each solution. No pre- or postoperative relationship between ghrelin and liking ratings were observed.

CONCLUSION

Gut hormone responses following bariatric surgery may contribute to taste processing of sugar+fat mixtures and together influence weight loss.

Associations among Visual, Auditory, and Olfactory Functions in Community-Based Older Adults: The Atherosclerosis Risk in Communities (ARIC) Study

PURPOSE

Objective examination of relationships among visual, hearing, and olfactory function may yield mechanistic insights and inform our understanding of the burden of multiple-sensory impairments.

METHODS

This cross-sectional study capitalized on continuous measures of visual acuity (VA), contrast sensitivity, pure tone audiometry, Quick Speech-in-Noise (QuickSIN), and Sniffin' Sticks from a subset of ARIC participants at two community sites (EyeDOC Study, 2017-2019). Scales of all measures were aligned such that higher values indicated greater impairment. Intersensory bivariate associations were assessed graphically, and correlations assessed using Kendall's tau. Intersensory associations, independent of age, education, smoking, diabetes, and hypertension, were examined using linear regression. Analyses were stratified by community/race (Washington County/White vs Jackson/Black) and sex (men vs women) to explore community-sex heterogeneity.

RESULTS

We included 834 participants (mean age, 79 years); 39% were from Jackson and 63% females. We found weak intersensory correlations (tau generally ≤0.15). In the demographics-adjusted regression models, results were heterogeneous across communities and sex. Worse near VA, contrast sensitivity, and olfaction were associated with worse QuickSIN and worse near VA was associated with worse olfaction in some but not all community/race-sex groups (e.g., Jackson/Black women, 0.1 logMAR worse near VA was associated with 0.27 units increase in QuickSIN [95% confidence interval, 0.10-0.45]). Associations were modestly attenuated by adjustment for the shared risk factors of smoking, diabetes, and hypertension.

CONCLUSIONS

Visual dysfunction showed little or no association with hearing or olfaction impairments, suggesting a modest role for shared risk factors.

TRANSLATIONAL RELEVANCE

Visually impaired individuals have only a modestly higher risk of other sensory impairment.

Associations of Prior Head Injury With Olfaction in Older Adults: Results From the Atherosclerosis Risk in Communities (ARIC) Study

Importance

Traumatic brain injury has been associated with short-term olfactory dysfunction, but the association of number of prior head injuries and head injury severity with both subjective and objective long-term olfactory function is less clear.

Objective

To investigate the associations of prior head injury, number of prior head injuries, and head injury severity with subjective and psychophysical (objective) olfactory function in older adults and to examine concordance between subjective and objective olfactory function among individuals with and without head injury.

Design, Setting, and Participants

This prospective cohort study included 5951 participants who attended Atherosclerosis Risk in Communities (ARIC) Study visit 5 (2011 through 2013). Data analysis was performed between November 2021 and May 2022.

Exposures

Head injury was defined by self-report and International Classification of Diseases codes.

Main Outcomes and Measures

Self-reported subjective olfactory dysfunction was assessed by the question, "Do you suffer from smell loss or a significantly decreased sense of smell?" Objective olfactory performance was assessed using the 12-item Sniffin' Sticks odor identification test.

Results

Overall, the 5951 participants were a mean (SD) age of 75.6 (5.2) years, 3501 (58.8%) were female, 1356 (22.8%) were of Black race, and 1666 (28.0%) had a history of head injury. Participants with prior head injury were more likely than individuals without prior head injury to report subjective olfactory dysfunction (24% vs 20%; difference, 4%; 95% CI, 1% to 6%) and have objective anosmia (15% vs 13%; difference, 2%; 95% CI, 0.1% to 4%) but had lower concordance between subjective and objective assessment (72% vs 77%; difference, -5%; 95% CI, -8% to -3%). In logistic regression models adjusted for sociodemographics and medical comorbidities including cognitive status, participants with a history of prior head injury, particularly individuals with 2 or more prior head injuries and more severe head injuries, were more likely to self-report subjective olfactory dysfunction and were more likely to be found to have objective anosmia compared with participants with no history of head injury.

Conclusions and Relevance

Findings of this cohort study provide evidence supporting the association between head injury and olfactory dysfunction, particularly among individuals who experienced multiple prior head injuries and among individuals with more severe head injury. The findings also suggest that individuals with prior head injury were more likely to both under-self-report and over-self-report deficits compared with objective olfactory testing; therefore, it may be important to consider objective olfactory testing in this patient population.

A comparative neuroimaging perspective of olfaction and higher-order olfactory processing: on health and disease

Olfactory dysfunction is often the earliest indicator of disease in a range of neurological and psychiatric disorders. One tempting working hypothesis is that pathological changes in the peripheral olfactory system where the body is exposed to many adverse environmental stressors may have a causal role for the brain alteration. Whether and how the peripheral pathology spreads to more central brain regions may be effectively studied in rodent models, and there is successful precedence in experimental models for Parkinson's disease. It is of interest to study whether a similar mechanism may underlie the pathology of psychiatric illnesses, such as schizophrenia. However, direct comparison between rodent models and humans includes challenges under light of comparative neuroanatomy and experimental methodologies used in these two distinct species. We believe that neuroimaging modality that has been the main methodology of human brain studies may be a useful viewpoint to address and fill the knowledge gap between rodents and humans in this scientific question. Accordingly, in the present review article, we focus on brain imaging studies associated with olfaction in healthy humans and patients with neurological and psychiatric disorders, and if available those in rodents. We organize this review article at three levels: 1) olfactory bulb (OB) and peripheral structures of the olfactory system, 2) primary olfactory cortical and subcortical regions, and 3) associated higher-order cortical regions. This research area is still underdeveloped, and we acknowledge that further validation with independent cohorts may be needed for many studies presented here, in particular those with human subjects. Nevertheless, whether and how peripheral olfactory disturbance impacts brain function is becoming even a hotter topic in the ongoing COVID-19 pandemic, given the risk of long-term changes of mental status associated with olfactory infection of SARS-CoV-2. Together, in this review article, we introduce this underdeveloped but important research area focusing on its implications in neurological and psychiatric disorders, with several pioneered publications.

The Neuroanatomic Correlates of Olfactory Identification Impairment in Healthy Older Adults and in Persons with Mild Cognitive Impairment

BACKGROUND

Olfactory identification (OI) impairment appears early in the course of Alzheimer's disease dementia (AD), prior to detectable cognitive impairment. However, the neuroanatomical correlates of impaired OI in cognitively normal older adults (CN) and persons with mild cognitive impairment (MCI) are not fully understood.

OBJECTIVE

We examined the neuroanatomic correlates of OI impairment in older adults from the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS).

METHODS

Our sample included 1,600 older adults without dementia who completed clinical assessment and structural brain imaging from 2011 to 2013. We characterized OI impairment using the 12-item Sniffin' Sticks odor identification test (score ≤6). We used voxel-based morphometry (VBM) and region of interest (ROI) analyses to examine the neuroanatomic correlates of impaired OI in CN and MCI, after adjusting for potential confounders. Analyses were also separately stratified by race and sex.

RESULTS

In CN, OI impairment was associated with smaller amygdala gray matter (GM) volume (p <  0.05). In MCI, OI impairment was associated with smaller GM volumes of the olfactory cortex, amygdala, entorhinal cortex, hippocampus, and insula (ps <  0.05). Differential associations were observed by sex in MCI; OI impairment was associated with lower insular GM volumes among men but not among women (p-interaction = 0.04). There were no meaningful interactions by race.

CONCLUSION

The brain regions associated with OI impairment in individuals without dementia are specifically those regions known to be the primary targets of AD pathogenic processes. These findings highlight the potential utility of olfactory assessment in the identification and stratification of older adults at risk for AD.

Hyperorality in Frontotemporal Dementia: Cognitive and Psychiatric Symptom Profiles in Early-Stage Disease

Hyperorality is a distinctive feature of the behavioral variant of frontotemporal dementia (bvFTD), but little is known about its significance in early-stage disease. This study examined the cognitive and psychiatric symptom profiles associated with hyperorality, using data from subjects with early-stage bvFTD enrolled in Alzheimer's Disease Research Centers. We found that hyperorality was not associated with cognitive performance, but was associated with psychosis, elation, and disinhibition. Hyperorality may share neurobiology with a subset of early psychiatric symptoms, a finding which could help identify targets for future treatment.

Altered Angular Gyrus Resting State Functional Connectivity Associated with Financial Capacity in Mild Cognitive Impairment

BACKGROUND

Financial capacity (FC) is a complex ability commonly impaired in older individuals with cognitive impairment; however, the underlying neural mechanisms are not well understood.

OBJECTIVE

To assess resting state functional connectivity using functional magnetic resonance imaging (rs-fMRI) in individuals with mild cognitive impairment (MCI) and impaired FC compared to cognitively normal older adults.

METHODS

rs-fMRI scans were obtained from individuals with MCI (N = 17) and normal older adults (N = 15). All participants completed the Financial Capacity Instrument Short Form (FCI-SF) and neuropsychological assessments. Based on previous findings, the left angular gyrus (lAG) was used as the seed region. Connectivity correlation coefficients were calculated for each seed-based connection that showed significantly altered connectivity. A Pearson's correlation was calculated between the connectivity correlation values from relevant regions and FC and other cognitive measures.

RESULTS

A total of 26 brain regions showed significantly increased functional connectivity with the lAG. Of these regions, 14 were identified as relevant to higher-level cognitive function for analysis. Pearson's correlations showed a significant negative correlation between the FCI-SF total score and increased connectivity between the IAG and the right temporal fusiform cortex (rTFC) (r = -0.455, p = 0.009).

CONCLUSION

Results showed a significant correlation between FC and increased functional connectivity between the lAG and the rTFC in cognitively normal older adults compared to participants with MCI. These exploratory findings suggest that cognitive functions play important roles in FC as the functional connectivity between the lAG and rTFC was not associated with other tests of executive or visuospatial cognition.

A Pilot Study of Self-Rated and Psychophysical Olfactory Dysfunction in Men Living with HIV

Background

Olfactory loss is associated with poor quality of life, malnutrition, and increased risk of depression, yet few studies have examined unawareness of olfactory dysfunction in men living with HIV (MLWH).

Method

MLWH (n = 51) completed olfaction self-ratings, psychophysical odor identification testing, cognitive measures, and questionnaires assessing smell habits, mood, cognitive failures, and quality of life. The sensitivity and specificity of olfactory self-ratings was calculated, and t-tests were used to examine factors contributing to discordance between self-rated and psychophysical olfaction dysfunction.

Results

We found that 33.3% (17 of 51 MLWH) of our sample demonstrated discordance between self-reported and psychophysical olfactory scores. Those unaware of olfaction dysfunction reported using less scented products in daily life but showed no other differences across demographic, clinical, or cognitive indices.

Conclusions

Our results cohere with prior studies of cognitively normal older adults, traumatic brain injury, and Parkinson's disease, which found that olfactory self-ratings may inadequately capture the full range of a person's olfactory status. Our work extends these findings to MLWH, with discordance rates ranging from 35 to 61% for self-rated and psychophysical olfactory dysfunction.

Implications

Given the differing rates of self-rated and psychophysical olfaction in our sample, psychophysical olfactory measures may be useful to consider in the neuropsychological assessment and clinical care of PLWH.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12078-022-09305-x.

Neural correlates of doubt in decision-making

The experience of doubt, the lack of confidence in one's perceptions, internal states, memory and attention, can be due to the variability in occurrence of a phenomenon or can be driven by the internal experience of uncertainty based on subjective evaluation of the environment. Although the experience of some doubt is adaptive in normal cognitive functioning, excessive doubt can significantly impair decision-making and in extreme cases give rise to psychopathology. Although neuroimaging studies have provided some insight into the network of brain areas that is engaged when decision-making involves uncertainty, it remains unclear if dysfunction in these areas also gives rise to the experience and pathological expression of doubt. This study examined the neural correlates of doubt using neuroimaging during the performance of a forced-choice perceptual decision-making task under varying levels of uncertainty in participants who reported either low or high doubt. Participants reporting high doubt exhibited increased activation in the bilateral inferior parietal lobule (IPL) during perceptual decision-making which was not observed in participants who reported low doubt. Furthermore, activity in the IPL in high doubt participants was associated with clinical measures of doubt and showed functional connectivity differences between the high and low doubt groups. The findings of the current study suggest a key role of the IPL and provide a network of brain regions that may play a role in the experience and expression of doubt.

Olfactory dysfunction and face processing of social cognition in first-episode psychosis

Olfactory functional deficits have been reported in psychotic disorders. Olfactory dysfunction has a predictive value for prognosis and disease course. Thus, it is important to know which specific symptoms and cognitive changes are associated with olfactory dysfunction in early-stage psychosis. Deficits in social cognition are a difficult problem in psychosis. Here we conduct a detailed assessment of odor function and face processing and show that odor discrimination capacity is specifically associated with face processing function in patients with first episode psychosis. This finding indicates that the high-throughput olfactory assessment may aid a prediction of the difficult clinical dimension from early-stage psychosis.

Functional Activities Detected in the Olfactory Bulb and Associated Olfactory Regions in the Human Brain Using T2-Prepared BOLD Functional MRI at 7T

Olfaction is a fundamental sense that plays a vital role in daily life in humans, and can be altered in neuropsychiatric and neurodegenerative diseases. Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) using conventional echo-planar-imaging (EPI) based sequences can be challenging in brain regions important for olfactory processing, such as the olfactory bulb (OB) and orbitofrontal cortex, mainly due to the signal dropout and distortion artifacts caused by large susceptibility effects from the sinonasal cavity and temporal bone. To date, few studies have demonstrated successful fMRI in the OB in humans. T2-prepared (T2prep) BOLD fMRI is an alternative approach developed especially for performing fMRI in regions affected by large susceptibility artifacts. The purpose of this technical study is to evaluate T2prep BOLD fMRI for olfactory functional experiments in humans. Olfactory fMRI scans were performed on 7T in 14 healthy participants. T2prep BOLD showed greater sensitivity than GRE EPI BOLD in the OB, orbitofrontal cortex and the temporal pole. Functional activation was detected using T2prep BOLD in the OB and associated olfactory regions. Habituation effects and a bi-phasic pattern of fMRI signal changes during olfactory stimulation were observed in all regions. Both positively and negatively activated regions were observed during olfactory stimulation. These signal characteristics are generally consistent with literature and showed a good intra-subject reproducibility comparable to previous human BOLD fMRI studies. In conclusion, the methodology demonstrated in this study holds promise for future olfactory fMRI studies in the OB and other brain regions that suffer from large susceptibility artifacts.

P–558 SNP array versus karyotype for prenatal diagnosis in fetuses with abnormal ultrasound: a systematic review and meta-analysis

Study question

Does Single nucleotide polymorphism (SNP) array provide a diagnostic advantage over conventional karyotype in prenatal diagnosis for fetuses with an abnormal ultrasound?

Summary answer

SNP array in the prenatal setting provides an incremental diagnostic yield over karyotype and the diagnostic accuracy is comparable with combined SNP array and karyotype

What is known already

Single nucleotide polymorphism and comparative genomic hybridization based arrays (aCGH) are the two chromosomal microarray (CMA) platforms available. Guidelines which recommend offering CMA instead of karyotyping for prenatal diagnosis are mainly based on studies that compared aCGH with karyotype. There is a paucity of reviews that critically appraise the role of SNP array as a prenatal diagnostic tool. We decided to estimate the incremental yield of SNP array over karyotype in detecting chromosomal abnormalities, and to determine the diagnostic accuracy of SNP alone compared with SNP array and karyotype in combination for prenatal diagnosis in fetuses with an abnormal ultrasound.

Study design, size, duration

We conducted a systematic review of studies comparing SNP array with karyotype for prenatal diagnosis in fetuses with an abnormal ultrasound. We performed a literature search in the electronic databases of EMBASE, PubMed, CENTRAL, CDSR, SCOPUS and Web of science for relevant studies published in the English language between January1996 and May 2020. We also hand searched the referenced list of included studies and performed a google search for grey literature to identify potential studies.

Participants/materials, setting, methods

The study population was women undergoing prenatal diagnosis for abnormal fetal ultrasound. Studies in which SNP array and karyotyping had been used in fetuses with abnormal ultrasound and which allowed for a 2 x 2 data extraction table were included. We estimated the incremental yields for SNP array over karyotype. For determining the diagnostic accuracy, we considered SNP array alone as the index test and combined karyotype & SNP array as the reference standard.

Main results and the role of chance

We included six studies for quantitative analysis. After pooling results, incremental yield of SNP array over normal karyotype was 10% (95% confidence interval, CI 4 to 16%) in fetuses with abnormal ultrasound while incremental yield of karyotype over SNP array was 1% (95% CI 0 to 2%). The agreement between SNP array and karyotype was 92%. Variant of uncertain significance (VUS) rates ranged from 4–8%.

For SNP array alone versus combined SNP array and conventional karyotype, pooled sensitivity and specificity was 0.96 (95% CI 0.91 to 0.99) and 1.00 (95% CI 0.99 to 1.00) respectively. The Area under curve (AUC) was 0.99 indicating the discriminating ability of the SNP array was very high to identify the fetus with chromosomal abnormalities.

Limitations, reasons for caution

Only studies published in English were included. There was some degree of heterogeneity in inclusion criteria for the included studies.

Wider implications of the findings: The current study suggests SNP array alone can replace conventional karyotype for prenatal diagnosis in fetus with an abnormal ultrasound. Limitations to adoption of SNP testing might include the requirement of requisite expertise to interpret the results and counsel patients appropriately, especially with the propensity of SNPs to identify VUS.

Trial registration number

Not applicable

Taste-related reward is associated with weight loss following bariatric surgery

BACKGROUNDBariatric surgeries are the most effective treatments for successful and sustained weight loss, but individuals vary in treatment response. Understanding the neurobiological and behavioral mechanisms accounting for this variation could lead to the development of personalized therapeutic approaches and improve treatment outcomes. The primary objectives of this study were to investigate changes in taste preferences and taste-induced brain responses after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) and to identify potential taste-related predictors of weight loss.METHODSFemales, ages 18 to 55, with a body mass index greater than or equal to 35 kg/m2, and approved for bariatric surgery at the Johns Hopkins Center for Bariatric Surgery were recruited for participation. Demographics, anthropometrics, liking ratings, and neural responses to varying concentrations of sucrose plus fat mixtures were assessed before and after surgery via visual analog scales and functional MRI.RESULTSBariatric surgery produced decreases in liking for sucrose-sweetened mixtures. Greater preference for sucrose-sweetened mixtures before surgery was associated with greater weight loss in RYGB, but not VSG. In the RYGB group only, individuals who showed lower taste-induced activation in the ventral tegmental area (VTA) before surgery and greater changes in taste-induced VTA activation 2 weeks following surgery experienced increased weight loss.CONCLUSIONThe anatomical and/or metabolic changes associated with RYGB may more effectively "reset" the neural processing of reward stimuli, thereby rescuing the blunted activation in the mesolimbic pathway found in patients with obesity. Further, these findings suggest that RYGB may be particularly effective in patients with a preference for sweet foods.FUNDINGNIH K23DK100559 and Dalio Philanthropies.

Differential Changes in Arteriolar Cerebral Blood Volume between Parkinson's Disease Patients with Normal and Impaired Cognition and Mild Cognitive Impairment (MCI) Patients without Movement Disorder - An Exploratory Study

Cognitive impairment amongst Parkinson's disease (PD) patients is highly prevalent and associated with an increased risk of dementia. There is growing evidence that altered cerebrovascular functions contribute to cognitive impairment. Few studies have compared cerebrovascular changes in PD patients with normal and impaired cognition and those with mild-cognitive-impairment (MCI) without movement disorder. Here, we investigated arteriolar-cerebral-blood-volume (CBVa), an index reflecting the homeostasis of the most actively regulated segment in the microvasculature, using advanced MRI in various brain regions in PD and MCI patients and matched controls. Our goal is to find brain regions with altered CBVa that are specific to PD with normal and impaired cognition, and MCI-without-movement-disorder, respectively. In PD patients with normal cognition (n=10), CBVa was significantly decreased in the substantia nigra, caudate and putamen when compared to controls. In PD patients with impaired cognition (n=6), CBVa showed a decreasing trend in the substantia nigra, caudate and putamen, but was significantly increased in the presupplementary motor area and intracalcarine gyrus compared to controls. In MCI-patients-without-movement-disorder (n=18), CBVa was significantly increased in the caudate, putamen, hippocampus and lingual gyrus compared to controls. These findings provide important information for efforts towards developing biomarkers for the evaluation of potential risk of PD dementia (PDD) in PD patients. The current study is limited in sample size and therefore is exploratory in nature. The data from this pilot study will serve as the basis for power analysis for subsequent studies to further investigate and validate the current findings.

Olfactory Testing in Temporal Lobe Epilepsy: a Systematic Review

PURPOSE OF REVIEW

Olfactory testing is a potentially safe, cost-effective, bedside evaluation tool for diagnosis, monitoring, and risk assessment for surgery in temporal lobe epilepsy (TLE) patients, but testing methods and relevant olfactory domains are not standardized. We conducted a systematic review to evaluate olfactory tests in TLE and summarize the results of the literature.

RECENT FINDINGS

Olfactory tests varied significantly in odorant administration tools and devices, target odorants, evaluation timing, and grading scales. The Smell Threshold Test and University of Pennsylvania Smell Identification Test were the most validated single-domain tests for odor detection and odor identification, respectively. For multi-domain tests, Odor Memory/Discrimination Test and the Sniffin' Sticks test were the most validated. Results of olfactory tests in TLE are presented by domain. Rigorous validation, standardization, and comparative analysis of existing olfactory tests by domain is urgently needed to establish the utility and efficacy of olfactory testing in TLE.

Odor identification predicts postoperative seizure control following magnetic resonance-guided laser interstitial thermal therapy

OBJECTIVE

Olfactory dysfunction has been well documented in individuals with temporal lobe epilepsy, but its use in presurgical planning has yet to be examined. We assessed the role of preoperative odor identification in mesial onset seizure localization utilizing stereoelectroencephalography (S-EEG) and magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) outcome.

METHODS

We identified 30 patients who had typical seizures captured during S-EEG monitoring or MRgLiTT of mesial temporal structures (n = 17 S-EEG, n = 13 MRgLiTT); seizure onset zone was classified as unilateral mesial seizure onset, or multifocal with unilateral mesial onset and nonmesial onset. Odor identification ability was assessed using the Sniffin' Sticks Odor Identification Test (SSOIT). Patients also completed measures of confrontation naming and auditory-verbal learning/memory using the Boston Naming Test and Hopkins Verbal Learning Test-Revised, respectively.

RESULTS

Overall, patients with intractable focal epilepsy exhibited poor olfactory performance (median [M] = 10.4, interquartile range [IQR] = 9.4-11.8). Of 19 patients who underwent MRgLiTT, 10 patients (52.6%) were seizure-free at last follow-up (M = 13 months, IQR =10-18). Patients who were seizure-free after MRgLiTT (n = 10) had poorer odor identification scores (M = 9, IQR = 7-13) compared to patients with seizure reoccurrence (M = 13, IQR = 12.5-15). Odor identification score was inversely associated with seizure freedom, with odds ratio = 0.60 (95% confidence interval [CI] = 0.38-0.95, P = .03). Receiver operating characteristic analysis revealed that an SSOIT score of 12 was the ideal cutoff for predicting favorable seizure outcome (area under the curve = 0.84, 95% CI = 0.64-1.0). Sensitivity was 88.9% and specificity was 78.9%, with a likelihood ratio of 2.9 of seizure failure in patients who had an odor identification score ≥ 12.

SIGNIFICANCE

Interictal olfactory dysfunction is commonly seen in patients with intractable focal epilepsy. Odor identification is a novel, noninvasive presurgical biomarker to distinguish who may or may not benefit from MRgLiTT of mesial temporal structures.

High Availability of the α7-Nicotinic Acetylcholine Receptor in Brains of Individuals with Mild Cognitive Impairment: A Pilot Study Using 18F-ASEM PET

Emerging evidence supports a hypothesized role for the α7-nicotinic acetylcholine receptor (α7-nAChR) in the pathophysiology of Alzheimer's disease. 18F-ASEM (3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-18F-fluorodibenzo[b,d]thiophene 5,5-dioxide) is a radioligand for estimating the availability of α7-nAChR in the brain in vivo with PET. Methods: In this cross-sectional study, 14 patients with mild cognitive impairment (MCI), a prodromal stage to dementia, and 17 cognitively intact, elderly controls completed 18F-ASEM PET. For each participant, binding in each region of interest was estimated using Logan graphical analysis with a metabolite-corrected arterial input function. Results: Higher 18F-ASEM binding was observed in MCI patients than in controls across all regions, supporting higher availability of α7-nAChR in MCI. 18F-ASEM binding was not associated with verbal memory in this small MCI sample. Conclusion: These data support use of 18F-ASEM PET to examine further the relationship between α7-nAChR availability and MCI.

Salivary 8-hydroxyguanosine levels in smokers and non-smokers with chronic periodontitis

This case-controlled clinical trial was performed on the salivary 8-hydroxyguanosine (8-OHdG) levels in smokers and non-smokers with chronic periodontitis after non-surgical periodontal therapy. Subjects (N = 40) with periodontitis (smokers and non-smokers) and with clinically healthy conditions (smokers and non-smokers) were assigned to this study. At baseline, clinical periodontal parameters (plaque index, gingival index, pocket probing depth and clinical attachment levels) were evaluated. Saliva samples were obtained pre- and post-treatment to quantify the 8-OHdG levels using Elisa technique. Subjects diagnosed with chronic periodontitis with smoking habit (CPs) and non-smokers (CPns) received scaling and root planing. In clinically healthy subjects with smoking habit (CHs) and non-smokers (CHns), only oral hygiene tutoring was performed. All clinical measurements and salivary collection were repeated in a 3-month recall interval. Data were analyzed using Anova, Tukey post hoc test and Mann-Whitney 'U' tests (P < 0.05). At baseline, CPs and CPns groups showed significantly higher PI, GI, PD and CAL values than those of CHns and CHs (P < 0.001). Baseline salivary levels of 8-OHdG were significantly higher in CPs group (14.775 pg/mL) (P < 0.001) compared to the other groups. All clinical parameters in chronic periodontitis group improved at the 3rd month recall interval, however, with regards to 8-OHdG values, the CP smoker category still had a higher level compared to CP non-smoker. This study reflects an on-going periodontal destructive status in smokers and salivary 8-OHdG levels could be recognized as an oxidative biomarker for determining periodontal tissue destruction.

Observational Study Examining the Association of Baseline Frailty and Postcardiac Surgery Delirium and Cognitive Change

BACKGROUND

Frailty is a geriatric syndrome thought to identify the most vulnerable older adults, and morbidity and mortality has been reported to be higher for frail patients after cardiac surgery compared to nonfrail patients. However, the cognitive consequences of frailty after cardiac surgery have not been well described. In this study, we examined the hypothesis that baseline frailty would be associated with postoperative delirium and cognitive change at 1 and 12 months after cardiac surgery.

METHODS

This study was nested in 2 trials, each of which was conducted by the same research team with identical measurement of exposures and outcomes. Before surgery, patients were assessed with the validated "Fried" frailty scale, which evaluates 5 domains (shrinking, weakness, exhaustion, low physical activity, and slowed walking speed) and classifies patients as nonfrail, prefrail, and frail. The primary outcome was postoperative delirium during hospitalization, which was assessed using the Confusion Assessment Method, Confusion Assessment Method for the Intensive Care Unit, and validated chart review. Neuropsychological testing was a secondary outcome and was generally performed within 2 weeks of surgery and then 4-6 weeks and 1 year after surgery, and the outcome of interest was change in composite Z-score of the test battery. Associations were analyzed using logistic and linear regression models, with adjustment for variables considered a priori (age, gender, race, education, and logistic European System for Cardiac Operative Risk Evaluation). Multiple imputation was used to account for missing data at the 12-month follow-up.

RESULTS

Data were available from 133 patients with baseline frailty assessments. Compared to nonfrail patients (13% delirium incidence), the incidence of delirium was higher in prefrail (48% delirium incidence; risk difference, 35%; 95% CI, 10%-51%) and frail patients (48% delirium incidence; risk difference, 35%; 95% CI, 7%-53%). In both univariable and multivariable models, the odds of delirium were significantly higher for prefrail (adjusted odds ratio, 6.43; 95% CI, 1.31-31.64; P = .02) and frail patients (adjusted odds ratio, 6.31; 95% CI, 1.18-33.74; P = .03) compared to nonfrail patients. The adjusted decline in composite cognitive Z-score was greater from baseline to 1 month only in frail patients compared to nonfrail patients. By 1 year after surgery, there were no differences in the association of baseline frailty with change in cognition.

CONCLUSIONS

Compared to nonfrail patients, both prefrail and frail patients were at higher risk for the primary outcome of delirium after cardiac surgery. Frail patients were also at higher risk for the secondary outcome of greater decline in cognition from baseline to 1 month, but not baseline to 1 year, after surgery.

A meta-analysis of neuropsychological, social cognitive, and olfactory functioning in the behavioral and language variants of frontotemporal dementia

BACKGROUND

Though meta-analyses of neuropsychological and social cognitive deficits in behavioral variant frontotemporal dementia (bvFTD) have been conducted, no study has comprehensively characterized and compared the neuropsychological, social cognitive, and olfactory profiles in the behavioral and language variants of FTD.

METHODS

Our search yielded 470 publications meeting inclusion criteria representing 11 782 FTD patients and 19 451 controls. For each domain, we calculated Hedges' g effect sizes, which represent the mean difference between the patient and control group divided by the pooled standard deviation. The heterogeneity of these effects was assessed with Cochran's Q-statistic using a random-effects model. Meta-regressions were employed to analyze the influence of demographic and disease characteristics.

RESULTS

Though semantic variant primary progressive aphasia patients showed the greatest impairment across all task types, the three groups showed similar cognitive effect sizes once contributions from the language subdomain were excluded from analysis. Contrary to expectation, the magnitude of deficits in executive functioning, social cognition and olfaction were comparable between the three subgroups. Among indices, a metric of executive errors distinguished the behavioral variant of FTD from the language phenotypes.

CONCLUSIONS

These data indicate that social cognitive and traditional executive functioning measures may not capture differences between FTD syndromes. These results have important implications for the interpretation of neuropsychological assessments, particularly when applied to the differential diagnosis of FTD. It is hoped that these findings will guide clinical and research assessments and spur new studies focused on improving the measurement of FTD syndromes.

Shaping anesthetic techniques to reduce post-operative delirium (SHARP) study: a protocol for a prospective pragmatic randomized controlled trial to evaluate spinal anesthesia with targeted sedation compared with general anesthesia in older adults undergoing lumbar spine fusion surgery

BACKGROUND

Postoperative delirium is common in older adults, especially in those patients undergoing spine surgery, in whom it is estimated to occur in > 30% of patients. Although previously thought to be transient, it is now recognized that delirium is associated with both short- and long-term complications. Optimizing the depth of anesthesia may represent a modifiable strategy for delirium prevention. However, previous studies have generally not focused on reducing the depth of anesthesia beyond levels consistent with general anesthesia. Additionally, the results of prior studies have been conflicting. The primary aim of this study is to determine whether reduced depth of anesthesia using spinal anesthesia reduces the incidence of delirium after lumbar fusion surgery compared with general anesthesia.

METHODS

This single-center randomized controlled trial is enrolling 218 older adults undergoing lumbar fusion surgery. Patients are randomized to reduced depth of anesthesia in the context of spinal anesthesia with targeted sedation using processed electroencephalogram monitoring versus general anesthesia without processed electroencephalogram monitoring. All patients are evaluated for delirium using the Confusion Assessment Method for 3 days after surgery or until discharge and undergo assessments of cognition, function, health-related quality of life, and pain at 3- and 12-months after surgery. The primary outcome is any occurrence of delirium. The main secondary outcome is change in the Mini-Mental Status Examination (or telephone equivalent) at 3-months after surgery.

DISCUSSION

Delirium is an important complication after surgery in older adults. The results of this study will examine whether reduced depth of anesthesia using spinal anesthesia with targeted depth of sedation represents a modifiable intervention to reduce the incidence of delirium and other long-term outcomes. The results of this study will be presented at national meetings and published in peer-reviewed journals with the goal of improving perioperative outcomes for older adults.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT03133845. This study was submitted to Clinicaltrials.gov on October 23, 2015; however, it was not formally registered until April 28, 2017 due to formatting requirements from the registry, so the formal registration is retrospective.