The Relationship Between the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Olfaction in Patients Referred for a Dementia Evaluation

Olfactory, Auditory, and Vestibular Performance: Multisensory Impairment Is Significantly Associated With Incident Cognitive Impairment

Background

Dysfunction in the olfactory, auditory, and vestibular systems are commonly seen in aging and are associated with dementia. The impact of sensory loss(es) on cognition is not well understood. Our aim was to assess the relationships between performance on objective multisensory testing and quantify the impact of dysfunction on cognition.

Methods

Patients presenting with subjective hearing loss presenting to a tertiary care otologic/audiologic clinic were identified and underwent multisensory testing using the Affordable, Rapid Olfactory Measurement Array (AROMA), pure tone audiometric evaluations, and the Timed “Up and Go” test. Cognitive impairment (CI) was assessed via the Montreal Cognitive Assessment (MoCA) was also administered.

Key Results

180 patients were enrolled. Thirty one percentage (n = 57) screened positive for cognitive impairment. When evaluating single sensory impairments, we found that olfactory dysfunction, gait impairment, and sensorineural hearing loss were all statistically significantly (p < 0.05) associated with a higher risk of cognitive impairment (ORs 3.89, 3.49, and 2.78, respectively) for CI. Multisensory impairment was significantly associated with cognitive impairment. Subjects with dysfunction in all domains were at the highest risk for cognitive impairment (OR 15.7, p < 0.001) vs. those with impairment in 2 domains (OR 5.32, p < 0.001).

Conclusion

Dysfunction of the olfactory, auditory, and vestibular systems is associated with a significantly increased risk of CI. The dramatically increased risk of CI with multisensory dysfunction in all three systems indicated that MSD may synergistically contribute to CI.

Olfactory Phenotypes Differentiate Cognitively Unimpaired Seniors from Alzheimer's Disease and Mild Cognitive Impairment: A Combined Machine Learning and Traditional Statistical Approach

BACKGROUND

Olfactory dysfunction (OD) is an early symptom of Alzheimer's disease (AD). However, olfactory testing is not commonly performed to test OD in the setting of AD.

OBJECTIVE

This work investigates objective OD as a non-invasive biomarker for accurately classifying subjects as cognitively unimpaired (CU), mild cognitive impairment (MCI), and AD.

METHODS

Patients with MCI (n = 24) and AD (n = 24), and CU (n = 33) controls completed two objective tests of olfaction (Affordable, Rapid, Olfactory Measurement Array -AROMA; Sniffin' Sticks Screening 12 Test -SST12). Demographic and subjective sinonasal and olfaction symptom information was also obtained. Analyses utilized traditional statistics and machine learning to determine olfactory variables, and combinations of variables, of importance for differentiating normal and disease states.

RESULTS

Inability to correctly identify a scent after detection was a hallmark of MCI/AD. AROMA was superior to SST12 for differentiating MCI from AD. Performance on the clove scent was significantly different between all three groups. AROMA regression modeling yielded six scents with AUC of the ROC of 0.890 (p < 0.001). Random forest model machine learning algorithms considering AROMA olfactory data successfully predicted MCI versus AD disease state. Considering only AROMA data, machine learning algorithms were 87.5%accurate (95%CI 0.4735, 0.9968). Sensitivity and specificity were 100%and 75%, respectively with ROC of 0.875. When considering AROMA and subject demographic and subjective data, the AUC of the ROC increased to 0.9375.

CONCLUSION

OD differentiates CUs from those with MCI and AD and can accurately predict MCI versus AD. Leveraging OD data may meaningfully guide management and research decisions.

Clinical Utility of β-Amyloid PET Imaging in People Living With HIV With Cognitive Symptoms

BACKGROUND

Imaging with β-amyloid (Aβ) positron emission tomography (PET) has the potential to aid the diagnosis of the cause of cognitive impairment affecting people living with HIV (PLWH) when neurodegenerative disorders are considered. We evaluated the clinical utility of [18F]Florbetaben (FBB) in PLWH with cognitive symptoms.

METHODS

Imaging with FBB PET was performed in 20 patients with cognitive concerns about dementia. Neuropsychological testing, plasma neurofilament light protein, plasma Aβ40, Aβ42, and cerebrospinal fluid Aβ42, tau, and HIV RNA were obtained. FBB PET images were assessed visually by 3 readers blinded to the clinical diagnosis and quantitatively by obtaining a composite cortical to cerebellar cortex standardized uptake value ratio (SUVR). FBB SUVR from 10 age-matched healthy controls was compared with SUVR of PLWH.

RESULTS

Most participants were men (90%) of white ethnicity (90%) with a median age (interquartile range) of 59 (43-79) years. Median CD4 count was 682 (74-1056). All patients were on combination antiretroviral therapy with plasma and cerebrospinal fluid HIV RNA <40 copies/mL. Fourteen patients had objective cognitive impairment including 2 who met clinical criteria for a diagnosis of dementia. No significant differences in composite SUVRs between PLWH and controls [mean (SD): 1.18 (0.03) vs. 1.16 (0.09); P = 0.37] were observed. Four patients were FBB+ with the highest SUVR in the posterior cingulate, superior temporal, and frontal superior lobe. Amyloid PET results contributed to a change in diagnosis and treatment for 10 patients.

CONCLUSION

[18F]Florbetaben PET has potential as an adjunctive tool in the diagnosis of PLWH with cognitive impairment, increasing diagnostic certainty and optimizing management.

Examination of Regression-based Discrepancy Scores for the RBANS in Detecting Cognitive Impairment from an Archival Sample

OBJECTIVE

The purpose of this study was to evaluate the clinical utility of regression-based formulas for the RBANS indexes in screening for cognitive impairment.

METHOD

A database of neuropsychological test results was created from archival records in a memory assessment clinic. The sample consisted of 83 individuals (37 males/46 females) with an average age of 70.1 (SD = 9.8) and 14.6 years of education (SD = 2.8). Diagnostic accuracy of regression-based predictions provided by Duff and Ramezani (2015) (Duff, K., & Ramezani, A. (2015). Regression-based normative formulae for the Repeatable Battery for the Assessment of Neuropsychological Status for older adults. Archives of Clinical Neuropsychology, 30, 600-604.) and from regression of WTAR standard score were examined via receiver operator characteristic curves. Preliminary generalizability investigation was completed using two additional datasets.

RESULTS

The WTAR was found to mediate the relationship between education and all RBANS index scores. The WTAR standard score was also found to contribute uniquely and significantly to the prediction of RBANS performance. Results of diagnostic accuracy analyses showed similar discriminating accuracy for all scores. There was limited support for using the WTAR over demographic variables alone in the estimation of RBANS performance; however, the WTAR was found to be more predictive than education, indicating potential clinical utility to using the word-reading score over just years of attained education.

CONCLUSIONS

Use of these derived Total Scale score variants is recommended for the screening of cognitive impairment, particularly in individuals with superior or poor educational quality. Further research is required to evaluate the utility of these variations in more diverse samples.

A meta-analysis of the accuracy of embedded performance validity indicators from the repeatable battery for the assessment of neuropsychological status

Objective: Meta-analyze the embedded performance validity tests of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), emphasizing two topics: diagnostic accuracy and relationships with demographics. Method: Literature was identified through a review of PsycINFO, PubMed, and Google Scholar. Bivariate linear mixed models were used for diagnostic accuracy analyses. Random-effects analysis of correlations with demographic variables was also used for the Effort Index. Results: Diagnostic accuracy analyses utilized 12 studies of the Effort Index (EI; N = 1469) and 6 studies of the Effort Scale (ES; N = 854). The EI was found to have a sensitivity of .44 (95% CI: .28 - .62), specificity of .87 (95% CI: .78 - .93), and diagnostic odds ratio (DOR) of 5.41 (95% CI: 3.74 - 7.58). The ES produced a sensitivity of .67 (95% CI: .50 - .81), specificity of .72 (95% CI: .53 - .85), and DOR of 5.97 (95% CI: 1.70 - 15.30). Meta-analysis of correlations utilized 14 samples of the EI (N = 3781), but insufficient data were available for the ES. Correlations between the EI and age (r = .10, 95% CI: .05 - .16), education (r = -.11, 95% CI: -.18 to -.04), and the RBANS Total Scale (r = -.45, 95% CI: -.62 to -.24) were significant. These results appeared to be robust to publication bias. Conclusion: Results support use of the EI over the ES; however, the latter is comparatively less studied and did not have similar variability in reported cut-off scores. ES accuracy statistics were significantly predicted by sample variables, which may be related to its relatively fewer studies. Both measures should be used cautiously in the context of genuine cognitive impairment.

The relationship between smell identification and neuropsychological domains: Results from a sample of community-dwelling adults suspected of dementia

OBJECTIVE

This study aimed to test the theoretical relationships between smell identification and cognitive tasks based on existing neuroimaging and anatomical findings.

METHOD

Utilizing data collected from a memory assessment clinic, theory-derived mediation and moderation models were tested. The sample used in this study consisted of 103 (39 male, 64 female) individuals referred for memory assessments. The sample's mean education was 12.4 years (SD = 3.2), and the mean age of the sample was 77.2 years (SD = 6.3).

RESULTS

The University of Pennsylvania Smell Identification Test (UPSIT) was a significant, partial mediator of the relationship between the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Immediate and Delayed Memory indexes. Olfactory identification did not mediate list learning and retrieval; however, olfactory identification was a significant partial mediator of the relationship between story encoding and later memory retrieval of the story. Olfactory identification also fully mediated the relationship between a visuospatial construction task and its reconstruction from memory after a short delay. The relationship between processing speed and the olfactory identification was significantly mediated by semantic memory. Finally, the UPSIT moderated the relationship between a measure of premorbid ability, the Wechsler Test of Adult Reading, and current global cognitive functioning.

CONCLUSIONS

Our results support theoretical relationships between olfaction and neuropsychological domains. Additionally, our results suggest that the UPSIT may serve as a proxy for cerebral integrity and is likely related to the duration of neurodegeneration.

Relationship between smell identification testing and the neuropsychological assessment of dementia in community-dwelling adults

The objective of this research was to investigate the relationship of the University of Pennsylvania Smell Identification Test (UPSIT) with neuropsychological tests and identify the utility of the UPSIT in detecting cognitive impairment. This research was an archival study of neuropsychological test results obtained from 70 clients (30 male/40 female) of a community-based memory clinic. The sample had an average age of 69.7 (SD = 9.7) and education of 14.6 (SD = 2.8) years. Hypotheses were tested using correlations, receiver operating characteristic (ROC) curves, and logistic regression. The UPSIT showed significant, weak to moderate correlations with neuropsychological tests. The UPSIT raw score correlated significantly with all but one cognitive ability domain. The UPSIT T-score was significantly correlated with all cognitive domains. Obtained areas under the ROC curve (AUC) for the UPSIT ranged from .60 to .87. The AUCs of the UPSIT did not differ significantly from verbal semantic fluency tests, but the Repeatable Battery for the Assessment of Neuropsychological Status Total Scale and Delayed Memory index tended to produce larger AUCs than the UPSIT. Results from step-wise logistic regressions suggest that the UPSIT raw score provides unique information beyond its relationship to age. Olfaction relates broadly to cognitive ability and may be sensitive to early symptoms of cognitive decline. Further research is needed to explore the relationships between smell identification tests and neuropsychological assessment.