Symbol Digit Modalities Test adaptation for Magnetic Resonance Imaging environment: A systematic review and meta-analysis

Altered angular gyrus activation during the digit symbol substitution test in people living with HIV: beyond information processing speed deficits

Speed-of-information processing (SIP) is often impaired in people living with HIV (PLWH), typically assessed through tests such as the digit symbol (DS) and symbol search, which also rely on motor and executive functions. This study aims to disentangle SIP deficits from other cognitive impairments in PLWH using an MRI-adapted digit symbol substitution test (mDSST). Fifty-seven PLWH (34.7 ± 11.2 years) and 50 age-matched people living without HIV (PLWoH, 31.8 ± 9.9 years) completed standardized neuropsychological tests and the mDSST. Behavioral performances and brain activations were compared, with correlations drawn between group-differentiating brain activations and clinical ratings of cognitive domains. Results showed that PLWH performed worse in DS and symbol search, made fewer responses, and was slower in mDSST, with performances correlating to SIP and motor ratings. Notably, PLWH showed greater deficits in attention compared to PLWoH, rather than in SIP or motor. PLWH also exhibited greater primary motor cortex activation and reduced right angular gyrus activation. These findings suggest that slower performances on SIP-related tests in PLWH may be partially linked to abnormal visuospatial attention, as reflected by reduced angular gyrus activation, with higher motor cortex activation potentially serving as a compensatory mechanism. Future studies should explore whether prefrontal regions implicated in SIP are impaired in more severely affected PLWH.

Weak brain function and anxiety-related loop in harm-avoidance personality: A resting-state functional magnetic resonance imaging study

BACKGROUND

Personality is a unique and relatively stable psychological concept that defines individual human beings. It strongly influences long-term behavioral styles such as emotional expression. This study aims to elucidate the brain functional underpinning behind personality.

METHODS

A total of 97 young subjects were included. All subjects completed personality, emotion, and cognition scales, and resting-state functional magnetic resonance imaging scan. All subjects were divided into subtypes of harm avoidance (HA) and reward dependence (RD) by clustering analysis. Graph theory analysis and network-based analysis were used to explore the brain functional configurations of personalities.

RESULTS

HA subjects showed lower network metrics (P = 0.018) and node metrics (P < 0.009). A negative component network was observed in HA subjects (P < 0.001). Functional topology metrics were negatively correlated with the HA score. The amygdala-IPG functional connectivity mediated the positive correlation between personality HA and state anxiety.

CONCLUSION

Personality HA is associated with decreased functional configuration, which could influence emotion by downregulating amygdala-IPG coupling. These findings provide insight into how the brain shapes personality and related emotions.

Characterization of changes in the resting-state intrinsic network in patients with diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is the most common complication of type 2 diabetes mellitus (T2DM) and is often accompanied by a variety of cognitive and emotional deficits, but the neurologic mechanisms underlying these deficits have not been fully elucidated. Therefore, this study aimed to use independent component analysis to explore the changes in the characteristics within the intrinsic network and to reveal patterns of interactions between networks in patients with DPN. Forty-one patients with T2DM who showed DPN, 37 patients with T2DM who did not show DPN (NDPN group), and 43 healthy controls (HC) underwent a neuropsychological assessment and resting-state functional magnetic resonance imaging examinations to examine the patterns of intra- and inter-network variations in the patients with T2DM at different clinical stages (with and without DPN). The relationships of intra- and inter-network functional connectivity (FC) with clinical/cognitive variables were also examined. In comparison with the NDPN group and HC, patients with DPN showed decreased FC within the visual network and sensorimotor network (SMN). Moreover, in comparison with the HC group, patients with DPN showed decreased FC within the anterior default mode network and increased FC within the basal ganglia network. Inter-network analysis showed decreased FC between the SMN and salience network in patients with DPN relative to the NDPN and HC groups. The decreased FC within the bilateral paracentral lobule (BA 6) of SMN was associated with Color Trails Test part 1 scores (r = -0.302, P = 0.007) and disease duration (r = -0.328, P = 0.003) in all patients with T2DM. In conclusion, the results revealed that patients with DPN have abnormal FC in multiple resting-state intrinsic networks in addition to the SMN, and that decreased FC between the SMN and salience network may be involved in the neural basis of abnormal sensorimotor function in patients with DPN.

Potential effects of peripheral neuropathy on brain function in patients with type 2 diabetes mellitus

Background

The mechanisms associated between diabetic peripheral neuropathy (DPN) and various brain function abnormalities in patients remains unclear. This study attempted to indirectly evaluate the effect of DPN on brain function in patients with type 2 diabetes mellitus (T2DM) by characterizing the resting-state functional connectivity (FC) of the lower limb sensorimotor cortex (LSM).

Methods

Forty-four T2DM patients with diabetic peripheral neuropathy (DPN), 39 T2DM patients without diabetic peripheral neuropathy (ND), and 43 healthy controls (HCs) underwent a neuropsychological assessment and resting-state functional magnetic resonance imaging examinations to examine the differences in FC between the LSM and the whole brain. The relationships of FC with clinical/cognitive variables were examined.

Results

In comparison with the HCs group, the ND group showed reduced FC of the LSM with the right lateral occipitotemporal cortex (LOTC) and increased FC with the medial superior frontal gyrus (SFGmed), while the DPN group showed reduced FC of the LSM with the right cerebellar lobule VI, the right LOTC, the rostral prefrontal cortex (rPFC), and the anterior cingulate gyrus (ACC). Moreover, in comparison with the ND group, the DPN group showed reduced FC of the LSM with the ACC, SFGmed, and rPFC. In the DPN group, the FC between the LSM and right cerebellar lobule VI was significantly correlated with fasting blood glucose levels (r = -0.490, p = 0.001), and that between the LSM and ACC was significantly correlated with the Montreal Cognitive Assessment score (r = 0.479, p = 0.001).

Conclusions

Patients with T2DM may show abnormal motion-related visual perceptual function before the appearance of DPN. Importantly, DPN can influence the brain regions that maintain motion and motor control, and this effect is not limited to motor function, which may be the central neuropathological basis for diabetic peripheral neuropathy.

Changes in 24(S)-Hydroxycholesterol Are Associated with Cognitive Performance in Early Huntington's Disease: Data from the TRACK and ENROLL HD Cohorts

BACKGROUND

There is evidence for dysregulated cholesterol homeostasis in Huntington's disease (HD). The brain-specific cholesterol metabolite 24(S)-hydroxycholesterol (24(S)-OHC) is decreased in manifest HD. 24(S)-OHC is an endogenous positive allosteric modulator (PAM) of the N-methyl-D-aspartate (NMDA) receptor, suggesting lower 24(S)-OHC may contribute to NMDA receptor hypofunction in HD. We hypothesized changes in 24(S)-OHC would be associated with cognitive impairment in early HD.

OBJECTIVE

To determine the interactions between oxysterols (24(S)-OHC, 25-OHC, and 27-OHC) at the NMDA receptor, the plasma levels of these oxysterols, and how these levels relate to cognitive performance.

METHODS

An in vitro competition assay was used to evaluate interactions at the NMDA receptor, liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) was used to measure plasma 24(S)-OHC, 25-OHC, and 27-OHC levels, and correlation analyses investigated their relationship to performance on cognitive endpoints in TRACK and ENROLL-HD (NCT01574053).

RESULTS

In vitro, 25-OHC and 27-OHC attenuated the PAM activity of 24(S)-OHC on the NMDA receptor. Lower plasma 24(S)-OHC levels and 24(S)/25-OHC ratios were detected in participants with early HD. Moderate and consistent associations were detected between plasma 24(S)/25-OHC ratio and performance on Stroop color naming, symbol digit modality, Trails A/B, and emotion recognition. Little association was observed between the ratio and psychiatric or motor endpoints, suggesting specificity for the relationship to cognitive performance.

CONCLUSIONS

Our findings support growing evidence for dysregulated CNS cholesterol homeostasis in HD, demonstrate a relationship between changes in oxysterols and cognitive performance in HD, and propose that NMDA receptor hypofunction may contribute to cognitive impairment in HD.

Altered Resting-State Brain Entropy in Cerebral Small Vessel Disease Patients with Cognitive Impairment

Objective: Cerebral small vessel disease (CSVD) is a primary vascular disease of cognitive impairment. Previous studies have predominantly focused on brain linear features. However, the nonlinear measure, brain entropy (BEN), has not been elaborated. Thus, this study aims to investigate if BEN abnormalities could manifest in CSVD patients with cognitive impairment. Methods: Thirty-four CSVD patients with cognitive impairment and 37 healthy controls (HCs) were recruited. Analysis of gray matter approximate entropy (ApEn) and sample entropy (SampEn) which are two indices of BEN was calculated. To explore whether BEN can provide unique information, we further performed brain linear methods, namely, amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo), to observe their differences. The ratios of BEN/ALFF and BEN/ReHo which represent the coupling of nonlinear and linear features were introduced. Correlation analysis was conducted between imaging indices and cognition. Subsequently, the linear support vector machine (SVM) was used to assess their discriminative ability. Results: CSVD patients exhibited lower ApEn and SamEn values in sensorimotor areas, which were correlated with worse memory and executive function. In addition, the results of BEN showed little overlap with ALFF and ReHo in brain regions. Correlation analysis also revealed a relationship between the two ratios and cognition. SVM analysis using BEN and its ratios as features achieved an accuracy of 74.64% (sensitivity: 86.49%, specificity: 61.76%, and AUC: 0.82439). Conclusion: Our study reveals that the reduction of sensorimotor system complexity is correlated with cognition. BEN exhibits distinctive characteristics in brain activity. Combining BEN and the ratios can be new biomarkers to diagnose CSVD with cognitive impairment. Impact Statement Cerebral small vessel disease (CSVD) is regarded as the most important vascular disease of cognitive impairment. However, conventional brain imaging fails to adequately elucidate the pathogenesis of cognitive disorder related to CSVD. In this regard, exploring brain entropy (BEN) based on resting-state functional magnetic resonance imaging (rs-fMRI) represents a relatively novel and unexplored approach in the context of CSVD. This approach provides novel insights into the pathogenesis, diagnosis, and rehabilitation of cognitive disorder associated with CSVD.

A preliminary investigation of sex differences in cognitive and fMRI changes following 28 days of cannabis abstinence

BACKGROUND

Previous studies have investigated the influence of cannabis on cognition among people with MS (pwMS), yet the influence of sex in the context of cannabis use remains unexplored. We aim to fill this gap by investigating cannabis-sex related differences in verbal learning, memory and processing speed in association with fMRI (resting state, and task-based) metrics.

METHOD

Our sample consisted of 19 long-term, frequent cannabis users (8 males, 11 females). Assessments were conducted at baseline and after 28 days of cannabis abstinence. The tests included measures of verbal memory (Selective Reminding Test (SRT)), working memory (n-back), information processing speed (Symbol Digit Modalities Test (SDMT)) and the resting state DMN. To evaluate the effects of cannabis abstinence, we performed a group x time interaction analysis using repeated measures ANCOVA. This analysis controlled for several covariates, including the level of disability (EDSS), baseline cannabis THC metabolite levels, and cannabis withdrawal symptoms. By controlling for these variables, we aimed to isolate the impact of cannabis abstinence on cognitive performance over time. Statistical significance was set at p < 0.05.

RESULTS

There were no baseline cognitive differences between the sexes. After 28 days of cannabis abstinence, females performed better on the Selective Reminding Test (SRT) (p = 0.04), with a large effect size (η² = 0.286). The mean correct response improved over time for females, but there was no statistically significant group x time interaction on the Symbol Digit Modalities Test (SDMT) and the n-back task. Resting state default mode network data showed overall increased activation in females relative to males at day 28, which meshed with lower brain activation during task-based fMRI paradigms.

CONCLUSION

Cannabis negated sex-based cognitive differences. Functional MRI task-based paradigms revealed less cerebral activation in females compared to males, which was associated with comparable or better cognitive performance in females, particularly after cannabis abstinence.

Dynamic effective connectivity in the cerebellar dorsal dentate nucleus and the cerebrum, cognitive impairment, and clinical correlates in patients with schizophrenia

BACKGROUND

Schizophrenia (SZ) is characterized by disconnected cerebral networks. Recent studies have shown that functional connectivity between the cerebellar dorsal dentate nucleus (dDN) and cerebrum is correlated with psychotic symptoms, and processing speed in SZ patients. Dynamic effective connectivity (dEC) is a reliable indicator of brain functional status. However, the dEC between the dDN and cerebrum in patients with SZ remains largely unknown.

METHODS

Resting-state functional MRI data, symptom severity, and cognitive performance were collected from 74 SZ patients and 53 healthy controls (HC). Granger causality analysis and sliding time window methods were used to calculate dDN-based dEC maps for all subjects, and k-means clustering was performed to obtain several dEC states. Finally, between-group differences in dynamic effective connectivity variability (dECV) and clinical correlations were obtained using two-sample t-tests and correlation analysis.

RESULTS

We detected four dEC states from the cerebrum to the right dDN (IN states) and three dEC states from the right dDN to the cerebrum (OUT states), with SZ group having fewer transitions in the OUT states. SZ group had increased dECV from the right dDN to the right middle frontal gyrus (MFG) and left lingual gyrus (LG). Correlations were found between the dECV from the right dDN to the right MFG and symptom severity and between the dECV from the right dDN to the left LG and working memory performance.

CONCLUSIONS

This study reveals a dynamic causal relationship between cerebellar dDN and the cerebrum in SZ and provides new evidence for the involvement of cerebellar neural circuits in neurocognitive functions in SZ.

Neurological Validation of ASD Diagnostic Criteria Using Frontal Alpha and Theta Asymmetry

Background/Objectives: Diagnosis of Autism Spectrum Disorder (ASD) relies on the observation of difficulties in social communication and interaction, plus the presence of repetitive and restrictive behaviors. The identification of neurological correlates of these symptoms remains a high priority for clinical research, and has the potential to increase the validity of diagnosis of ASD as well as provide greater understanding of how the autistic brain functions. This study focused on two neurological phenomena that have been previously associated with psychiatric disorders (alpha- and theta-wave asymmetry across the frontal region of the brain), and tested for their association with the major diagnostic criteria for ASD. Methods: A total of 41 male autistic youth underwent assessment with the Autism Diagnostic Observation Schedule (ADOS-2) and 3 min of eyes-closed resting EEG to collect alpha- and theta-wave data from right and left frontal brain sites. Results: Different associations were found for theta versus alpha asymmetry and the ADOS-2 subscales, across different brain regions responsible for a varying range of cognitive functions. In general, theta asymmetry was associated with conversation with others, sharing of enjoyment, and making social overtures, whereas alpha asymmetry was linked with making eye contact, reporting events to others, and engaging in reciprocal social communication. Specific brain regions involved are identified, as well as implications for clinical practice. Conclusions: Specific autism symptoms may be associated with selected brain region activity, providing a neurological basis for diagnosis and treatment.

Theta burst stimulation on the fronto-cerebellar connective network promotes cognitive processing speed in the simple cognitive task

Background

The fronto-cerebellar functional network has been proposed to subserve cognitive processing speed. This study aims to elucidate how the long-range frontal-to-cerebellar effective connectivity contributes to faster speed.

Methods

In total, 60 healthy participants were randomly allocated to three five-daily sessions of transcranial magnetic stimulation conditions, namely intermittent theta-burst stimulation (iTBS, excitatory), continuous theta-burst stimulation (CTBS, inhibitory), or a sham condition. The sites of the stimulations were the right pre-supplementary motor area (RpSMA), medial cerebellar vermis VI (MCV6), and vertex, respectively. Performances in two reaction time tasks were recorded at different time points.

Results

Post-stimulation speeds revealed marginal decreases in the simple but not complex task. Nevertheless, participants in the excitatory RpSMA and inhibitory MCV6 conditions showed direct and negative path effects on faster speeds compared to the sham condition in the simple reaction time (SRT) task (β = -0.320, p = 0.045 and β = -0.414, p = 0.007, respectively). These path effects were not observed in the SDMT task.

Discussion

RpSMA and MCV6 were involved in promoting the path effects of faster reaction times on simple cognitive task. This study offers further evidence to support their roles within the long-range frontal-to-cerebellar connectivity subserving cognitive processing speed. The enhancement effects, however, are likely limited to simple rather than complex mental operations.

Changes in processing speed during early abstinence from alcohol dependence

BACKGROUND

Processing speed is a task-independent construct underpinning more complex goal-related abilities. Processing speed is impaired in alcohol dependence (AD) and is linked to relapse, as are the functions it underpins. Reliable measurement of processing speed may allow tracking of AD recovery trajectories and identify patients requiring additional support.

AIMS

To assess changes in reaction time (RT) from baseline (at the start of a detoxification programme) across early abstinence.

METHODS

Vibrotactile RT was assessed in early recovery between days 3 and 7 of treatment in 66 individuals with AD (25 females; aged 19-74, 44.60 ± 10.60 years) and against 35 controls tested on one occasion (19 females; 41.00 ± 13.60), using two multivariate multiple regressions. A mixed multivariate analysis of covariance (MANCOVA) of available AD data (n = 45) assessed change in RT between timepoints and between treatment settings (outpatient vs inpatient).

RESULTS

The group (AD vs control) significantly predicted choice RT at baseline and follow-up but did not significantly predict simple RT or RT variability, which is inconsistent with previous findings. At follow-up, mental fatigue was also predicted by the group, and MANCOVA indicated that this had worsened in inpatients but improved in outpatients.

CONCLUSIONS

Recovery of RT measures so early in the treatment journey was not in line with previous research which indicates persisting deficits. The interaction between setting and timepoint indicates that despite being typically less medically complex, outpatients require ongoing support and monitoring during their recovery.

Effects and mechanisms of computerized cognitive training in Huntington's disease: protocol for a pilot study

Huntington's disease (HD) causes progressive cognitive decline, with no available treatments. Computerized cognitive training (CCT) has shown efficacy in other populations, but its effects in HD are largely unknown. This pilot study will explore the effects and neural mechanisms of CCT in HD. The intervention group participants will complete 12 weeks of multidomain CCT. Control group participants will receive lifestyle education and access to CCT after the study. The primary outcome is change in processing speed. Secondary outcomes include - change in other cognitive domains, functional brain network connectivity (derived from MRI) and psychosocial function. Feasibility outcomes include rates of recruitment, adherence and retention. This study may provide insights into the effects of CCT in HD and guide future trials.Clinical Trial Registration: ACTRN12622000908730 (ClinicalTrials.gov).

Association between degree centrality and neurocognitive impairments in patients with Schizophrenia: A Longitudinal rs-fMRI Study

BACKGROUND

Evidence indicates that patients with schizophrenia (SZ) experience significant changes in their functional connectivity during antipsychotic treatment. Despite previous reports of changes in brain network degree centrality (DC) in patients with schizophrenia, the relationship between brain DC changes and neurocognitive improvement in patients with SZ after antipsychotic treatment remains elusive.

METHODS

A total of 74 patients with acute episodes of chronic SZ and 53 age- and sex-matched healthy controls were recruited. The Positive and Negative Syndrome Scale (PANSS), Symbol Digit Modalities Test, digital span test (DST), and verbal fluency test were used to evaluate the clinical symptoms and cognitive performance of the patients with SZ. Patients with SZ were treated with antipsychotics for six weeks starting at baseline and underwent MRI and clinical interviews at baseline and after six weeks, respectively. We then divided the patients with SZ into responding (RS) and non-responding (NRS) groups based on the PANSS scores (reduction rate of PANSS ≥50%). DC was calculated and analyzed to determine its correlation with clinical symptoms and cognitive performance.

RESULTS

After antipsychotic treatment, the patients with SZ showed significant improvements in clinical symptoms, semantic fluency performance. Correlation analysis revealed that the degree of DC increase in the left anterior inferior parietal lobe (aIPL) after treatment was negatively correlated with changes in the excitement score (r = -0.256, p = 0.048, adjusted p = 0.080), but this correlation failed the multiple test correction. Patients with SZ showed a significant negative correlation between DC values in the left aIPL and DST scores after treatment, which was not observed at the baseline (r = -0.359, p = 0.005, adjusted p = 0.047). In addition, we did not find a significant difference in DC between the RS and NRS groups, neither at baseline nor after treatment.

CONCLUSIONS

The results suggested that DC changes in patients with SZ after antipsychotic treatment are correlated with neurocognitive performance. Our findings provide new insights into the neuropathological mechanisms underlying antipsychotic treatment of SZ.

Longitudinal Effects of Elexacaftor/Tezacaftor/Ivacaftor: Multidimensional Assessment of Neuropsychological Side Effects and Physical and Mental Health Outcomes in Adolescents and Adults

BACKGROUND

Italy initiated elexacaftor/tezacaftor/ivacaftor (ETI) for people with cystic fibrosis (pwCF) in July 2021. It has led to dramatic improvements in lung function, BMI, sweat chloride, and respiratory symptoms. However, few data are available on side effects or effects on a broad range of outcomes.

RESEARCH QUESTION

How does ETI affect mental health, cognitive processing, neuropsychological side effects, GI symptoms, and health-related quality of life over time?

STUDY DESIGN AND METHODS

This was a prospective, "real-world" longitudinal study. Participants were recruited consecutively and evaluated at initiation (T0) and after 1 month, 3 months, and 6 months of starting treatment. Assessments included depression (nine-item Patient Health Questionnaire), anxiety (seven-item Generalized Anxiety Disorder), cognition (Symbol Digit Modalities Test), GI Symptom Tracker, and health-related quality of life (Cystic Fibrosis Questionnaire-Revised). Based on literature, an ad hoc questionnaire was developed to assess side effects: insomnia, headache, memory problems, "brain fog," and concentration problems. Following descriptive analyses, longitudinal data were analyzed by using mixed models for repeated measures, controlling for age and sex when appropriate.

RESULTS

Ninety-two consecutive pwCF (female/male, 46/46; mean age, 25.4 years) participated. FEV1 increased initially and then remained stable. BMI also increased significantly from T0 to 6 months (P < .01). Depression improved from T0 to 1 month (P < .001); however, no changes in anxiety were found. Cognitive processing improved from T0 to subsequent assessments. Positive changes were reported on the GI Symptom Tracker for stools and adherence challenges, although no changes were found for abdominal pain and digestion. Side effects occurred in 10% to 29%, with no reduction over time; insomnia increased significantly across time. Female participants reported more side effects than male participants (ie, insomnia, headache, concentration problems, brain fog).

INTERPRETATION

This prospective study evaluated the effects of ETI using multiple measures. Significant improvements were found in many domains; however, side effects were reported by a substantial proportion of pwCF, with no improvements over time. Female participants reported more side effects than male participants. pwCF should be followed up systematically to assess the frequency of side effects after starting this new modulator.

Altered resting-state brain oscillation and the associated cognitive impairments in late-life depression with different depressive severity: An EEG power spectrum and functional connectivity study

OBJECTIVE

Cognitive impairments are prevalent in late-life depression (LLD). However, it remains unclear whether there are concurrent brain oscillation alterations in resting condition across varying level of depression severity. This cross-sectional study aims to investigate the characteristics of altered resting-state oscillations, including power spectrum and functional connectivity, and their association with the cognitive impairments in LLD with different depression severity.

METHODS

A total of 65 patients with LLD and 40 elder participants without depression were recruited. Global cognition and subtle cognitive domains were evaluated. A five-minute resting-state electroencephalography (EEG) was conducted under eyes-closed conditions. Measurements included the ln-transformed absolute power for power spectrum analysis and the weighted phase lag index (wPLI) for functional connectivity analysis.

RESULTS

Attentional and executive dysfunction were exhibited in Moderate-Severe LLD group. Enhanced posterior upper gamma power was observed in both LLD groups. Additionally, enhanced parietal and fronto-parietal/occipital theta connectivity were observed in Moderate-Severe LLD group, which were associated with the attentional impairment.

LIMITATIONS

Limitations include a small sample size, concomitant medication use, and a relatively higher proportion of females.

CONCLUSIONS

Current study observed aberrant brain activity patterns in LLD across different levels of depression severity, which were linked to cognitive impairments. The altered posterior brain oscillations may be trait marker of LLD. Moreover, cognitive impairments and associated connectivity alterations were exhibited in moderate-severe group, which may be a state-like marker of moderate-to severe LLD. The study deepens understanding of cognitive impairments with the associated oscillation changes, carrying implications for neuromodulation targets in LLD.

The relationship between cognitive reserve focused on leisure experiences and cognitive functions in bipolar patients

Bipolar disorder (BP) is characterized by cognitive decline. Individual differences exist in maintaining cognitive function due to daily physical activity and sleep. We examined the relationship between leisure experiences as proxies for cognitive reserve (CR) and cognitive function in patients with bipolar disorder after adjusting for daily physical activity and sleep. The CR of patients with BP (n = 24) and healthy study controls (HC) (n = 24) was assessed using premorbid IQ, years of education, and leisure activity history. Performance-based neuropsychological tests were performed to evaluate cognitive function. A self-reported scale was used to assess resilience. Physical activity and sleep were measured using an activity meter. Verbal fluency, story memory, and verbal memory were significantly positively correlated with the kinds of leisure experiences in patients with BP. A hierarchical regression analysis accounting for confounding factors showed that verbal fluency and memory were associated with the kinds of leisure experiences. Neither years of education nor resilience were significantly associated with neuropsychological scores. Various leisure experiences in patients with BP are associated with higher language-related cognitive functioning. Engaging in various leisure experiences may affect higher cognitive functions related to language.

Disrupted Gray Matter Networks Associated with Cognitive Dysfunction in Cerebral Small Vessel Disease

This study aims to investigate the disrupted topological organization of gray matter (GM) structural networks in cerebral small vessel disease (CSVD) patients with cerebral microbleeds (CMBs). Subject-wise structural networks were constructed from GM volumetric features of 49 CSVD patients with CMBs (CSVD-c), 121 CSVD patients without CMBs (CSVD-n), and 74 healthy controls. The study used graph theory to analyze the global and regional properties of the network and their correlation with cognitive performance. We found that both the control and CSVD groups exhibited efficient small-world organization in GM networks. However, compared to controls, CSVD-c and CSVD-n patients exhibited increased global and local efficiency (Eglob/Eloc) and decreased shortest path lengths (Lp), indicating increased global integration and local specialization in structural networks. Although there was no significant global topology change, partially reorganized hub distributions were found between CSVD-c and CSVD-n patients. Importantly, regional topology in nonhub regions was significantly altered between CSVD-c and CSVD-n patients, including the bilateral anterior cingulate gyrus, left superior parietal gyrus, dorsolateral superior frontal gyrus, and right MTG, which are involved in the default mode network (DMN) and sensorimotor functional modules. Intriguingly, the global metrics (Eglob, Eloc, and Lp) were significantly correlated with MoCA, AVLT, and SCWT scores in the control group but not in the CSVD-c and CSVD-n groups. In contrast, the global metrics were significantly correlated with the SDMT score in the CSVD-s and CSVD-n groups but not in the control group. Patients with CSVD show a disrupted balance between local specialization and global integration in their GM structural networks. The altered regional topology between CSVD-c and CSVD-n patients may be due to different etiological contributions, which may offer a novel understanding of the neurobiological processes involved in CSVD with CMBs.

Inhibitory dysfunction may cause prospective memory impairment in temporal lobe epilepsy (TLE) patients: an event-related potential study

Introduction

Prospective memory (PM) is the ability to remember future intentions, and PM function is closely related to independence in daily life, particularly in patients with temporal lobe epilepsy (TLE). As PM involves various cognitive components of attention, working memory, inhibition and other executive functions, this study investigated how TLE may affect PM components and the underlying neural mechanisms.

Methods

Sixty-four subjects were recruited, including 20 refractory TLE patients, 18 well-controlled TLE patients and 26 age-matched healthy controls. A set of neuropsychological tests was administered to assess specific brain functions. An event-related potential (ERP) task was used to further explore how PM and its components would be differentially affected in the two TLE types.

Results

Our findings revealed that: (1) refractory TLE patients scored lower than the healthy controls in the digit span, Verbal Fluency Test and Symbol Digit Modalities Test; (2) refractory TLE patients exhibited impaired PM performance and reduced prospective positivity amplitudes over the frontal, central and parietal regions in ERP experiments when compared to the healthy controls; and (3) decreased P3 amplitudes in the nogo trials were observed over the frontal-central sites in refractory but not in well-controlled TLE patients.

Discussion

To our knowledge, this is the first ERP study on PM that has specifically identified PM impairment in refractory but not in well-controlled TLE patients. Our finding of double dissociation in PM components suggests that inhibition dysfunction may be the main reason for PM deficit in refractory TLE patients. The present results have clinical implications for neuropsychological rehabilitation in TLE patients.

Neural Substrates of Psychomotor Speed Deficits in Cerebral Small Vessel Disease: A Brain Disconnectome Mapping Study

It remains unknown which factors influence how brain disconnectivity derived from White Matter Hyperintensity (WMH) lesions leads to psychomotor speed dysfunction, one of the earliest and most common cognitive manifestations in the cerebral Small Vessel Disease (cSVD) population. While the burden of WMH has been strongly linked to psychomotor speed performance, the effect that different locations and volumes of WMH may have on cSVD-related cognitive impairment remains unclear. Therefore, we aimed to explore (1) whether global WMH, deep WMH (DWMH), and periventricular (PVWMH) volumes display different psychomotor speed associations; (2) whether tract-specific WMH volume shows stronger cognitive associations compared with global measures of WMH volume; (3) whether specific patterns of WMH location lead to different degrees of disconnectivity. Using the BCBToolkit, we investigated which pattern of distribution and which locations of WMH lesion result in impaired psychomotor speed in a well-characterized sample (n = 195) of cSVD patients without dementia. Two key findings emerge from our study. First, global (and not tract-specific) measures of WMH volume were associated with psychomotor speed performance. Second, disconnection maps revealed the involvement of callosal tracts, association and projection fibers, and frontal and parietal cortical brain areas related to psychomotor speed, while the lesion location influenced such associations. In conclusion, psychomotor deficits are affected differently by WMH burden and topographic distribution through brain disconnection in non-demented cSVD patients.

Intermittent theta burst stimulation vs. high-frequency repetitive transcranial magnetic stimulation for post-stroke cognitive impairment: Protocol of a pilot randomized controlled double-blind trial

Introduction

Intermittent theta burst stimulation (iTBS), a novel mode of transcranial magnetic stimulation (TMS), has curative effects on patients with post-stroke cognitive impairment (PSCI). However, whether iTBS will be more applicable in clinical use than conventional high-frequency repetitive transcranial magnetic stimulation (rTMS) is unknown. Our study aims to compare the difference in effect between iTBS and rTMS in treating PSCI based on a randomized controlled trial, as well as to determine its safety and tolerability, and to further explore the underlying neural mechanism.

Methods

The study protocol is designed as a single-center, double-blind, randomized controlled trial. Forty patients with PSCI will be randomly assigned to two different TMS groups, one with iTBS and the other with 5 Hz rTMS. Neuropsychological evaluation, activities of daily living, and resting electroencephalography will be conducted before treatment, immediately post-treatment, and 1 month after iTBS/rTMS stimulation. The primary outcome is the change in the Montreal Cognitive Assessment Beijing Version (MoCA-BJ) score from baseline to the end of the intervention (D11). The secondary outcomes comprise changes in resting electroencephalogram (EEG) indexes from baseline to the end of the intervention (D11) as well as the Auditory Verbal Learning Test, the symbol digit modality test, the Digital Span Test findings, and the MoCA-BJ scores from baseline to endpoint (W6).

Discussion

In this study, the effects of iTBS and rTMS will be evaluated using cognitive function scales in patients with PSCI as well as data from resting EEG, which allows for an in-depth exploration of underlying neural oscillations. In the future, these results may contribute to the application of iTBS for cognitive rehabilitation of patients with PSCI.

Cognitive skill learning in multiple sclerosis: A meaningful component of the neuropsychological profile

Cognitive skill learning (CSL) refers to the capacity to improve performance on specific cognitive operations through repeated practice. We hypothesized that high CSL aptitude may promote accumulation of cognitive reserve, and resiliency to cognitive decline, in people with Multiple Sclerosis (MS). Using an adaptive working memory training paradigm, we obtained CSL aptitude indices (amount of improvement on the training task over time) in MS patients for a single session of practice (25-30 min), and longer-term practice (twenty sessions). Neuropsychological performance was assessed with the Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), and the Raven's Advanced Progressive Matrices (RAPM). CSL aptitude measures were positively correlated with neuropsychological performance, and had high diagnostic accuracy for classifying cognitive impairment in MS, defined as 1.5 SD below the demographics-corrected normative mean of the SDMT. Positive relationships between CSL aptitude measures and neuropsychological performance tended to be more pronounced for individuals with high estimated cognitive reserve, suggesting that high CSL aptitude is a a factor that promotes the protective effects of cognitive reserve. Furthermore, regression analyses indicated that CSL aptitude is separable from baseline cognitive capacity. The findings suggest that CSL aptitude impacts the neuropsychological profile in MS, and may be a factor underlying variance in cognitive resiliency.

Cognitive Complaints Assessment and Neuropsychiatric Disorders After Mild COVID-19 Infection

OBJECTIVES

This study aimed to analyze cognitive impairment associated with long-term coronavirus disease 2019 (COVID-19) syndrome and its correlation with anxiety, depression, and fatigue in patients infected with severe acute respiratory syndrome coronavirus.

METHODS

This was a cross-sectional study of 127 patients with COVID-19. Tests to screen for neuropsychiatric symptoms included the Fatigue Severity Scale, Mini-Mental State Exam 2 (MMSE-2), Symbol Digit Modalities Test (SDMT), and Hospital Anxiety and Depression Scale.

RESULTS

In cognitive tests, SDMT was abnormal in 22%, being more sensitive than MMSE-2 to detect cognitive changes. Furthermore, although manifestations such as fatigue, depression, and anxiety were frequent in the post-COVID-19 phase, these 3 conditions, known to contribute to cognitive impairment, were slightly correlated with worse performance on the rapid screening tests.

CONCLUSIONS

In patients with mild COVID-19 and cognitive complaints, SDMT helped to confirm disturbances in the attention domain and processing speed.

Brain Activation During Working Memory Task in Amnestic Mild Cognitive Impairment Patients and Its Association with Memory and Attention

BACKGROUND

Amnestic mild cognitive impairment (aMCI) is regarded as a transitional state of Alzheimer's disease, with working memory (WM) impairment.

OBJECTIVE

To investigate the brain activity in aMCI patients during WM tasks with the functional near-infrared spectroscopy (fNIRS) technique, as well as explore the association between brain activity and cognitive function in multiple domains.

METHODS

This study is a case-control study of 54 aMCI patients and 33 cognitively healthy elderly (NC). All participants underwent neuropsychological assessments. fNIRS was applied to examine the brain activation during the WM task. Multivariable linear regression analysis was applied to evaluate associations between brain activation and cognitive function in multiple domains.

RESULTS

Compared to NC subjects, aMCI patients had lower activation in the bilateral prefrontal, parietal, and occipital cortex during the WM task. Additionally, activation in the left prefrontal, bilateral parietal, and occipital cortex during the encoding and maintenance phase was positively associated with memory function. During memory retrieval, higher activity in the left prefrontal, parietal, and occipital cortex were correlated with higher memory scores. Besides, a positive association also formed between attention function and the activation in the left prefrontal, parietal, and occipital cortex during the WM task.

CONCLUSION

These findings demonstrated that reduced activation in the prefrontal, parietal and occipital cortex during WM might reflect the risk of cognitive impairment, especially memory and attention function in aMCI patients. Given the brain activation visualization, fNIRS may be a convenient and alternative tool for screening the risk of Alzheimer's disease.

Increased low frequency fluctuation in the brain after acupuncture treatment in CSVDCI patients: A randomized control trial study

Background

Cerebral small vessel disease (CSVD) is one of two cognition-impairing diseases. Acupuncture (Acu) is a flexible treatment with few adverse effects and is thus widely used to treat neurological problems.

Methods

We recruited a total of 60 patients and assigned them to two groups (n = 30 each group). During the study, some participants were excluded by quality control, and a total of 44 subjects (25 Acu and 19 controls) were completed to investigate the therapeutic efficacy of acupuncture on CSVD cognitive impairment (CSVDCI). The following demographic and clinical variables were compared between the two groups: gender, age, education, smoking, alcohol, Montreal cognitive assessment (MoCA), symbol digit modalities test (SDMT), verbal fluency test (VFT), digit span task (DST), Boston naming test (BNT) scores, and amplitude of low-frequency fluctuation (ALFF) under the typical band (0.01-0.08 Hz). Mixed effect analysis was utilized to test for differences between the two groups before and after the treatment.

Results

Following acupuncture treatment, the Acu group scored higher on MoCA, SDMT, VFT, DST, and BNT compared to controls (P < 0.05). The brain regions showing substantially greater ALFF values in the Acu group were the right inferior temporal gyrus, left middle occipital gyrus, left superior occipital gyrus, left insula, bilateral postcentral gyrus, right superior parietal gyrus, right cerebellum, right precuneus, and right precentral gyrus (P < 0.005, no correction). The ALFF values in the right inferior temporal gyrus (P = 0.027), left middle occipital gyrus (P = 0.005), left superior occipital gyrus (P = 0.011), and right superior parietal gyrus (P = 0.043) were positively associated with MoCA.

Conclusion

We found that acupuncture modulates the functional activity of temporal, occipital, and parietal regions of the brain in CSVDCI patients.

Performance in information processing speed is associated with parietal white matter tract integrity in multiple sclerosis

Background

The Symbol Digit Modalities Test (SDMT) is most frequently used to test processing speed in patients with multiple sclerosis (MS). Functional imaging studies emphasize the importance of frontal and parietal areas for task performance, but the influence of frontoparietal tracts has not been thoroughly studied. We were interested in tract-specific characteristics and their association with processing speed in MS patients.

Methods

Diffusion tensor imaging was obtained in 100 MS patients and 24 healthy matched controls to compare seed-based tract characteristics descending from the superior parietal lobule [Brodman area 7A (BA7A)], atlas-based tract characteristics from the superior longitudinal fasciculus (SLF), and control tract characteristics from the corticospinal tract (CST) and their respective association with ability on the SDMT.

Results

Patients had decreased performance on the SDMT and decreased white matter volume (each p &lt; 0.05). The mean fractional anisotropy (FA) for the BA7A tract and CST (p &lt; 0.05), but not the SLF, differed between MS patients and controls. Furthermore, only the FA of the SLF was positively associated with SDMT performance even after exclusion of the lesions within the tract (r = 0.25, p &lt; 0.05). However, only disease disability and total white matter volume were associated with information processing speed in a linear regression model.

Conclusions

Processing speed in MS is associated with the structural integrity of frontoparietal white matter tracts.

Development of a Brain-Computer Interface-Based Symbol Digit Modalities Test and Validation in Healthy Elderly Volunteers and Stroke Patients

Standard cognitive assessment tools often involve motor or verbal responses, making them impossible for severely motor-disabled individuals. Brain-computer interfaces (BCIs) are expected to help severely motor-impaired individuals to perform cognitive assessment because BCIs can circumvent motor and verbal requirements. Currently, the field of research to develop cognitive tasks based on BCI is still in its nascent stage and needs further development. This study explored the possibility of developing a BCI version of symbol digit modalities test (BCI-SDMT). Steady-state visual evoked potential (SSVEP) was adopted to build the BCI and a 9-target SSVEP-BCI was realized to send examinees' responses. A training-free algorithm (i.e., filter bank canonical correlation analysis) was used for SSVEP identification. Thus, examinees are able to start the proposed BCI-SDMT immediately. Eighty-nine healthy elderly volunteers and 9 stroke patients were enrolled to validate the technical feasibility of the developed BCI-SDMT. For all participants, the average recognition accuracies of the developed BCI and BCI-SDMT were 93.89 ± 8.48% and 92.58 ± 10.52%, respectively, were considerably above the chance level (i.e., 11.11%). These results indicated that both healthy elderly volunteers and stroke patients could elicit sufficient SSVEPs to control the BCI. Furthermore, patient use of the developed BCI-SDMT was unaffected by the presence of motor impairment. They could understand instructions, pair numbers with specific symbols, and send commands using the BCI. The proposed BCI-SDMT can be used as a complement to the existing versions of the SDMT and has the potential to evaluate cognitive abilities in individuals with severe motor disabilities.

Comparative Study on Topological Properties of the Whole-Brain Functional Connectome in Idiopathic Rapid Eye Movement Sleep Behavior Disorder and Parkinson’s Disease Without RBD

Purpose

Idiopathic rapid eye movement Sleep Behavior Disorder (iRBD) is considered as a prodromal and most valuable warning symptom for Parkinson’s disease (PD). Although iRBD and PD without RBD (nRBD-PD) are both α-synucleinopathies, whether they share the same neurodegeneration process is not clear enough. In this study, the pattern and extent of neurodegeneration were investigated and compared between early-stage nRBD-PD and iRBD from the perspective of whole-brain functional network changes.

Methods

Twenty-one patients with iRBD, 23 patients with early-stage nRBD-PD, and 22 matched healthy controls (HCs) were enrolled. Functional networks were constructed using resting-state functional MRI (fMRI) data. Network topological properties were analyzed and compared among groups by graph theory approaches. Correlation analyses were performed between network topological properties and cognition in the iRBD and nRBD-PD groups.

Results

Both patients with iRBD and patients with early-stage nRBD-PD had attention, executive function, and some memory deficits. On global topological organization, iRBD and nRBD-PD groups still presented small-worldness, but both groups exhibited decreased global/local efficiency and increased characteristic path length. On regional topological organization, compared with HC, nRBD-PD presented decreased nodal efficiency, decreased degree centrality, and increased nodal shortest path length, while iRBD presented decreased nodal efficiency and nodal shortest path. For iRBD, brain regions with decreased nodal efficiency were included in the corresponding regions of nRBD-PD. Nodal shortest path changes were significantly different in terms of brain regions and directions between nRBD-PD and iRBD. Attention deficits were correlated with local topological properties of the occipital lobe in both iRBD and nRBD-PD groups.

Conclusion

Both global and local efficiency of functional networks declined in nRBD-PD and iRBD groups. The overlaps and differences in local topological properties between nRBD-PD and iRBD indicate that iRBD not only shares functional changes of PD but also presents distinct features.

Perspectives before incremental trans-disciplinary cross-validation of clinical self-evaluation tools and functional MRI in psychiatry: 10 years later

Translational validity (or trans-disciplinary validity) is defined as one possible approach to achieving incremental validity by combining simultaneous clinical state-dependent measures and functional MRI data acquisition. It is designed under the assumption that the simultaneous administration of the two methods may produce a dataset with enhanced synchronization and concordance. Translational validation aims at "bridging" the explanatory gap by implementing validated psychometric tools clinically in the experimental settings of fMRI and then translating them back to clinical utility. Our studies may have identified common diagnostic task-specific denominators in terms of activations and network modulation. However, those common denominators need further investigation to determine whether they signify disease or syndrome-specific features (signatures), which, at the end of the day, raises one more question about the poverty of current conventional psychiatric classification criteria. We propose herewith a novel algorithm for translational validation based on our explorative findings. The algorithm itself includes pre-selection of a test based on its psychometric characteristics, adaptation to the functional MRI paradigm, exploration of the underpinning whole brain neural correlates in healthy controls as compared to a patient population with certain diagnoses, and finally, investigation of the differences between two or more diagnostic classes.

Communication Styles and Attention Performance in Primary School Children

Communication styles are the three communication patterns that result from merging the verbal elements of communication, the non-verbal elements and the paraverbal elements. The objective of this study was to test what effect different communication styles have on attention performance in primary school children. We administered the assertive behavior scale for children (CABS), the symbol digit modalities test (SDMT) and the d2 attention test to a sample of 77 participants of primary school. A statistically significant and proportional correlation was found between the assertive communication style and the total number of correct answers of the SDMT. We also found positive correlations between the assertive communication style and d2 attention test performance. Children with an assertive communication style have better attention performance than children with passive or aggressive communication styles.

Outcome measures assisting treatment optimization in multiple sclerosis

Objective

To review instruments used to assess disease stability or progression in persons with multiple sclerosis (pwMS) that can guide clinicians in optimizing therapy.

Methods

A non-systematic review of scientific literature was undertaken to explore modalities of monitoring symptoms and the disease evolution of MS.

Results

Multiple outcome measures, or tools, have been developed for use in MS research as well as for the clinical management of pwMS. Beginning with the Expanded Disability Status Scale, introduced in 1983, clinicians and researchers have developed monitoring modalities to assess all aspects of MS and the neurological impairment it causes.

Conclusions

Much progress has been made in recent decades for the management of MS and for the evaluation of disease progression. New technology, such as wearable sensors, will provide new opportunities to better understand changes in function, dexterity, and cognition. Essential work over the decades since EDSS was introduced continues to improve our ability to treat this debilitating disease.

Domain-Specific Cognitive Trajectories Among Patients with Minor Stroke or Transient Ischemic Attack in a 6-Year Prospective Asian Cohort: Serial Patterns and Indicators

BACKGROUND

Long-term post-stroke cognitive impairment (PSCI) has often been overlooked, especially among patients with minor stroke or transient ischemic attack (TIA).

OBJECTIVE

To assess 6-year domain-specific cognitive trajectories among survivors of minor stroke or TIA and to identify possible indicators associated with cognitive trajectories, as well as long-term and incident PSCI.

METHODS

Eligible participants completed cognitive and clinical assessments at baseline (2 weeks after stroke) and up to 5 follow-up visits in 6 years. Mixed linear models and generalized estimating equations were adopted to analyze longitudinal data and survival analysis to explore incident PSCI, controlling for demographic, clinical, and vascular indicators.

RESULTS

The prevalence of PSCI and mortality rate ranged from 34.6% to 53.7%, and 0 to 7.7% respectively, among 244 patients. Incidence of PSCI was 21.9%. While visual memory demonstrated a significant improvement (p <  0.05), other cognitive domains showed a fluctuating yet stable pattern across visits (all ps >  0.05). Besides age, baseline IQCODE (attention: -0.218 SD/y, executive function: -0.238 SD/y, visual memory: -0.266 SD/y), and MoCA improvement within 1 year (visuoconstruction: 0.007 SD/y, verbal memory: 0.012 SD/y) were associated with longitudinal cognitive changes. Baseline MoCA (OR = 0.66, 95% CI = [0.59-0.74]), MoCA improvement within 3-6 months (OR = 0.79, 95% CI = [0.71-0.89], and within 1 year (OR = 0.86, 95% CI = [0.76-0.96]) were associated with long-term PSCI, while baseline MoCA (OR = 0.76, 95% CI = [0.61-0.96]) was also associated with incident PSCI.

CONCLUSION

While most domains remained stable across-time, visual memory demonstrated an overall improvement. Short-term cognitive improvement could be an early indicator of long-term cognitive trajectory to identify individuals who may be resilient to PSCI.

The Cerebellum Is Related to Cognitive Dysfunction in White Matter Hyperintensities

Objective

White matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is frequently presumed to be secondary to cerebral small vessel disease (CSVD) and associated with cognitive decline. The cerebellum plays a key role in cognition and has dense connections with other brain regions. Thus, the aim of this study was to investigate if cerebellar abnormalities could occur in CSVD patients with WMHs and the possible association with cognitive performances.

Methods

A total of 104 right-handed patients with WMHs were divided into the mild WMHs group (n = 39), moderate WMHs group (n = 37), and severe WMHs group (n = 28) according to the Fazekas scale, and 36 healthy controls were matched for sex ratio, age, education years, and acquired resting-state functional MRI. Analysis of voxel-based morphometry of gray matter volume (GMV) and seed-to-whole-brain functional connectivity (FC) was performed from the perspective of the cerebellum, and their correlations with neuropsychological variables were explored.

Results

The analysis revealed a lower GMV in the bilateral cerebellum lobule VI and decreased FC between the left- and right-sided cerebellar lobule VI with the left anterior cingulate gyri in CSVD patients with WMHs. Both changes in structure and function were correlated with cognitive impairment in patients with WMHs.

Conclusion

Our study revealed damaged GMV and FC in the cerebellum associated with cognitive impairment. This indicates that the cerebellum may play a key role in the modulation of cognitive function in CSVD patients with WMHs.

Altered anterior default mode network dynamics in progressive multiple sclerosis

BACKGROUND

Modifications in brain function remain relatively unexplored in progressive multiple sclerosis (PMS), despite their potential to provide new insights into the pathophysiology of the disease at this stage.

OBJECTIVES

To characterize the dynamics of functional networks at rest in patients with PMS, and the relation with clinical disability.

METHODS

Thirty-two patients with PMS underwent clinical and cognitive assessment. The dynamic properties of functional networks, retrieved from transient brain activity, were obtained from patients and 25 healthy controls (HCs). Sixteen HCs and 19 patients underwent a 1-year follow-up (FU) clinical and imaging assessment. Differences in the dynamic metrics between groups, their longitudinal changes, and the correlation with clinical disability were explored.

RESULTS

PMS patients, compared to HCs, showed a reduced dynamic functional activation of the anterior default mode network (aDMN) and a decrease in its opposite-signed co-activation with the executive control network (ECN), at baseline and FU. Processing speed and visuo-spatial memory negatively correlated to aDMN dynamic activity. The anti-couplings between aDMN and auditory/sensory-motor network, temporal-pole/amygdala, or salience networks were differently associated with separate cognitive domains.

CONCLUSION

Patients with PMS presented an altered aDMN functional recruitment and anti-correlation with ECN. The aDMN dynamic functional activity and interaction with other networks explained cognitive disability.

Spinocerebellar Ataxia Type 1: One-Year Longitudinal Study to Identify Clinical and MRI Measures of Disease Progression in Patients and Presymptomatic Carriers

Spinocerebellar ataxias type 1 (SCA1) is an autosomal dominant disease usually manifesting in adulthood. We performed a prospective 1-year longitudinal study in 14 presymptomatic mutation carriers (preSCA1), 11 ataxic patients, and 21 healthy controls. SCA1 patients had a median disease duration of 6 years (range 2-16) and SARA score of 7 points (range 3.5-20). PreSCA1 had an estimated time before disease onset of 9.7 years (range 4-30), and no signs of ataxia. At baseline, SCA1 patients significantly differed from controls in SARA score (Scale for Assessment and Rating of Ataxia), cognitive tests, and structural MRI measures. Significant volume loss was found in cerebellum, brainstem, basal ganglia, and cortical thinning in frontal, temporal, and occipital regions. PreSCA1 did not differ from controls. At 1-year follow-up, SCA1 patients showed significant increase in SARA score, and decreased volume of cerebellum (- 0.6%), pons (- 5.5%), superior cerebellar peduncles (- 10.7%), and midbrain (- 3.0%). Signs of disease progression were also observed in preSCA1 subjects, with increased SARA score and reduced total cerebellar volume. Our exploratory study suggests that clinical scores and MRI measures provide valuable data to monitor and quantify the earliest changes associated with the preclinical and the symptomatic phases of SCA1 disease.

Supplementation with Matured Hop Bitter Acids Improves Cognitive Performance and Mood State in Healthy Older Adults with Subjective Cognitive Decline

BACKGROUND

Prevention of age-related cognitive decline and depression is becoming urgent because of rapid growing aging populations. Effects of vagal nerve activation on brain function by food ingredients are inadequately investigated; matured hop bitter acid (MHBA) administration reportedly improves cognitive function and depression via vagal nerve activation in model mice.

OBJECTIVE

We investigated the effects of MHBA supplementation on cognitive function and mood state in healthy older adults with perceived subjective cognitive decline.

METHODS

Using a randomized double-blind placebo-controlled trial design, 100 subjects (aged 45-69 years) were randomly assigned into placebo (n = 50) and MHBA (n = 50) groups, and received placebo or MHBA capsules daily for 12 weeks.

RESULTS

Symbol Digit Modalities Test (SDMT) score assessing divided attention at week 12 was significantly higher (p = 0.045) and β-endorphin at week 12 was significantly lower (p = 0.043) in the subjects receiving MHBA. Transthyretin in serum, a putative mild cognitive impairment marker, was significantly higher at week 12 in the MHBA group than in the placebo group (p = 0.048). Subgroup analysis classified by the subjective cognitive decline questionnaire revealed that in addition to improved SDMT scores, memory retrieval assessed using the standard verbal paired-associate learning tests and the Ray Verbal Learning Test at week 12 had significantly improved in the subgroup with perceived subjective cognitive decline and without requirement for medical assistance in the MHBA group compared with that in the placebo group.

CONCLUSION

This study suggested that MHBA intake improves cognitive function, attention, and mood state in older adults.

Computerized Symbol Digit Modalities Test in a Swiss Pediatric Cohort Part 1: Validation

OBJECTIVE

The objective of this study was to validate the computerized Symbol Digit Modalities Test (c-SDMT) in a Swiss pediatric cohort, in comparing the Swiss sample to the Canadian norms. Secondly, we evaluated sex effects, age-effects, and test-retest reliability of the c-SDMT in comparison to values obtained for the paper and pencil version of the Symbol Digit Modalities Test (SDMT).

METHODS

This longitudinal observational study was conducted in a single-center setting at the University Children's Hospital of Bern. Our cohort consisted of 86 children (45 male and 41 female) aged from 8 to 16 years. The cohort included both healthy participants (n = 38) and patients (n = 48) hospitalized for a non-neurological disease. Forty eight participants were assessed during two testing sessions with the SDMT and the c-SDMT.

RESULTS

Test-retest reliability was high in both tests (SDMT: ICC = 0.89, c-SDMT: ICC = 0.90). A reliable change index was calculated for the SDMT (RCIp = -3.18, 14.01) and the c-SDMT (RCIp = -5.45, 1.46) corrected for practice effects. While a significant age effect on information processing speed was observed, no such effect was found for sex. When data on the c-SDMT performance of the Swiss cohort was compared with that from a Canadian cohort, no significant difference was found for the mean time per trial in any age group. Norm values for age groups between 8 and 16 years in the Swiss cohort were established.

CONCLUSION

Norms for the c-SDMT between the Swiss and the Canadian cohort were comparable. The c-SDMT is a valid alternative to the SDMT. It is a feasible and easy to administer bedside tool due to high reliability and the lack of motor demands.

Dynamics of Cortical Degeneration Over a Decade in Huntington's Disease

BACKGROUND

Characterizing changing brain structure in neurodegeneration is fundamental to understanding long-term effects of pathology and ultimately providing therapeutic targets. It is well established that Huntington's disease (HD) gene carriers undergo progressive brain changes during the course of disease, yet the long-term trajectory of cortical atrophy is not well defined. Given that genetic therapies currently tested in HD are primarily expected to target the cortex, understanding atrophy across this region is essential.

METHODS

Capitalizing on a unique longitudinal dataset with a minimum of 3 and maximum of 7 brain scans from 49 HD gene carriers and 49 age-matched control subjects, we implemented a novel dynamical systems approach to infer patterns of regional neurodegeneration over 10 years. We use Bayesian hierarchical modeling to map participant- and group-level trajectories of atrophy spatially and temporally, additionally relating atrophy to the genetic marker of HD (CAG-repeat length) and motor and cognitive symptoms.

RESULTS

We show, for the first time, that neurodegenerative changes exhibit complex temporal dynamics with substantial regional variation around the point of clinical diagnosis. Although widespread group differences were seen across the cortex, the occipital and parietal regions undergo the greatest rate of cortical atrophy. We have established links between atrophy and genetic markers of HD while demonstrating that specific cortical changes predict decline in motor and cognitive performance.

CONCLUSIONS

HD gene carriers display regional variability in the spatial pattern of cortical atrophy, which relates to genetic factors and motor and cognitive symptoms. Our findings indicate a complex pattern of neuronal loss, which enables greater characterization of HD progression.

Symbol Digit Modalities Test: Greek Normative Data for the Oral and Written Version and Discriminative Validity in Patients with Multiple Sclerosis

OBJECTIVES

The purpose of this study was to generate normative data on the Symbol Digits Modalities Test (SDMT) for the written and oral versions in the Greek adult population. We also investigated the test's validity in discriminating the performance of healthy adults from two groups of adults diagnosed with relapsing remitting (RRMS) and secondary progressive (SPMS) multiple sclerosis.

METHOD

The sample consisted of 609 healthy men and women between the ages of 18 and 65. All participants were monolingual native Greek adult speakers. Each healthy participant was administered either the written (n = 460) or oral (n = 149) versions of the SDMT. Discriminant validity was examined by comparing 35 healthy participants who had completed the oral version of the SDMT to 35 age - and education-matched RRMS and SPMS patients.

RESULTS

Linear regression models explained between 36% and 55% of the variance in the SDMT oral and written version scores. Age was the strongest predictor of difference in SDMT written and oral version performance, followed by education that also accounted for a further proportion of the SDMT variance. On the contrary, gender was found not to contribute significantly to the variance in the SDMT for either the written or the oral versions. As a result, age- and education-adjusted norms were generated. Regarding the tests discriminative validity, we found that both MS patient groups scored significantly lower than the healthy group.

CONCLUSIONS

This is the first study to provide comprehensive normative data for the SDMT in the adult population in Greece, impacting the future practice of neuropsychological assessment in this country.

Experience of South American MS and/or NMOSD experts in practice during the COVID-19 pandemic: Focus on Telemedicine

Background

COVID-19 pandemic has changed the way to manage MS and NMOSD, not only concerning treatment, but also regarding social distance and the increasing use of telemedicine (TM) to minimize the risk of infection. Currently, there is no data regarding TM among MS and NMOSD South American experts.

Objective

To investigate TM experiences from South American MS and/or NMOSD experts in the follow-up of their patients focusing on TM.

Methods

A cross-sectional study was performed. 141 MS and/or NMOSD experts from Argentina, Chile, Colombia and Brazil were invited to answer an web-based survey.

Results

A total of 129 (91.48 %) experts completed the survey. Only 19.4% had experience in TM previous COVID-19 pandemic, while 79.8% are currently using TM, most using video call (52.3%). Using TM, 44.1% of the experts were able to perform neurological examination, 85.6% believed to be able to identify a relapse, 48.6% use Patient Determined Disease Steps and 38.7% kept using the conventional Expanded Disability Status Scale.

Conclusion

Our survey demonstrates preparedness and responsiveness among South American MS and/or NMOSD experts.  Despite scarce prior TM experience, most experts felt confident to use TM as a new tool for monitoring their patients.

Connectome-based models can predict processing speed in older adults

Decrement in processing speed (PS) is a primary cognitive morbidity in clinical populations and could significantly influence other cognitive functions, such as attention and memory. Verifying the usefulness of connectome-based models for predicting neurocognitive abilities has significant translational implications on clinical and aging research. In this study, we verified that resting-state functional connectivity could be used to predict PS in 99 older adults by using connectome-based predictive modeling (CPM). We identified two distinct connectome patterns across the whole brain: the fast-PS and slow-PS networks. Relative to the slow-PS network, the fast-PS network showed more within-network connectivity in the motor and visual networks and less between-network connectivity in the motor-visual, motor-subcortical/cerebellum and motor-frontoparietal networks. We further verified that the connectivity patterns for prediction of PS were also useful for predicting attention and memory in the same sample. To test the generalizability and specificity of the connectome-based predictive models, we applied these two connectome models to an independent sample of three age groups (101 younger adults, 103 middle-aged adults and 91 older adults) and confirmed these models could specifically be generalized to predict PS of the older adults, but not the younger and middle-aged adults. Taking all the findings together, the identified connectome-based predictive models are strong for predicting PS in older adults. The application of CPM to predict neurocognitive abilities can complement conventional neurocognitive assessments, bring significant clinical benefits to patient management and aid the clinical diagnoses, prognoses and management of people undergoing the aging process.

Changes in structural and functional connectivity during two years of fingolimod therapy for multiple sclerosis

BACKGROUND

Fingolimod, an oral drug, has been reported to reduce relapse rate in multiple sclerosis (MS). However disease progression may still occur in spite of control of inflammation. Functional imbalances within and between cerebral networks associated with disruption of structural and functional network integrity, have been reported in MS. An effective therapy is expected to stabilize such functional network integrity.

OBJECTIVE

The purpose of this study was to investigate changes in structural and resting-state functional connectivity of motor and cognitive networks, and associated changes in neurologic scores in MS, during 2 years of fingolimod therapy.

METHODS

Twenty five subjects with MS were recruited for this study. Subjects were scanned with diffusion tensor imaging (DTI) and resting-state functional connectivity MRI (fcMRI) scan protocol at 3 T with 6-month interval over a period of 2 years. Neurologic performance scores of motor and cognitive performances were also obtained.

RESULTS

DTI measures worsened during the 1st year and then stabilized; any trend of stabilization of fcMRI was delayed until the 2nd year. While motor performance did not change, cognitive performance showed improvement. Several baseline DTI measures correlated with relevant neurologic scores.

CONCLUSION

Initial worsening of motor and cognitive network was reported after 1 year of treatment, but seems DTI and fcMRI measures seem to stabilize after around one year fingolimod therapy.

Non-classical behavior of the default mode network regions during an information processing task

The default mode network (DMN) efficient deactivation and suppressed functional connectivity (FC) during goal-directed tasks, which require attentional resources, have been considered essential to healthy brain cognition. However, recent studies have shown that DMN regions do not always show the expected behavior. Then, we aimed to investigate the functional activation and connectivity of DMN nodes in young, healthy controls during a goal-directed task. We used an adaptation of the symbol digit modalities test (SDMT) to evaluate the information processing speed (IPS). Twenty-four subjects (10 women, age: 29 ± 7 years) underwent two functional Magnetic Resonance Imaging experiments: one during resting-state and one during a block-designed SDMT paradigm. We superimposed the templates of the DMN on the group activation map and observed the reorganization of the network. For the posterior cingulate cortex (PCC) node of the DMN, which is spatially extensive, comprising the precuneus (dorsal portion) and the posterior cingulate gyrus (PCG, ventral portion), the extent of each region was different between conditions, suggesting different functional roles for them. Therefore, for the functional connectivity (FC) analysis, we split the DMN-PCC region into two regions: left precuneus (BA 7) and PCG. The left precuneus (BA 7) was positively correlated with the left lingual gyrus (BA 17), a task-positive region, and negatively associated with the DMN nodes when comparing task performance with the resting-state condition. The other DMN regions presented the classical antagonistic role during the attentional task. In conclusion, we found that the activation and functional connectivity of the DMN is, in general, suppressed during the information processing. However, the left precuneus BA 7 presented a context-dependent modulatory behavior, working as a transient in-between hub connecting the DMN to task-positive areas. Such findings support studies that show increased activation and excitatory functional connectivity of DMN portions during goal-directed tasks. Moreover, our results may contribute to defining more precise functional correlates of IPS deficits in a wide range of clinical and neurological diseases.

Functional representation of the symbol digit modalities test in relapsing remitting multiple sclerosis

BACKGROUND

The Symbol Digit Modalities Test (SDMT) is essential in the screening of cognitive impairments in multiple sclerosis (MS). Methodological adaptions of the SDMT on functional MRI exist, but without specific investigation of more cognitive components of information processing speed (IPS). Additionally, there is only limited data on functional differences between MS-patients and healthy controls (HC).

METHODS

20 MS-patients and 20 HC were investigated executing the original version of the SDMT on fMRI. We analyzed (1) neural networks as indicated in the methodological adaptions (i.e. frontal (Brodman area BA6, BA9), parietal (BA7), occipital (BA17) and cerebellar), (2) functional activations of cognitive components of IPS and (3) functional differences between MS and HC during SDMT.

RESULTS

MS patients performed worse during the SDMT. Both groups demonstrated activation on each region of interest. Cognitive component of IPS was driven by superior parietal and posterior cerebellar activation. MS-patients showed decreased cingulate activation during SDMT as compared to HC.

CONCLUSION

The original SDMT task revealed comparable fMRI-activation sites as reported for previous adaptions. Cognitive components of IPS depend on superior parietal and medial posterior cerebellar regions known to process visuo-spatial integration and anticipation. Attention related areas in the cingulate cortex were decreased in MS-patients.

Assessing disability and relapses in multiple sclerosis on tele-neurology

BACKGROUND

As a consequence of the coronavirus disease 2019 (COVID-19) pandemic, a large amount of consultations will be delivered through tele-medicine, especially for diseases causing chronic disability and requiring immunomodulatory treatments, such as multiple sclerosis (MS).

METHODS

We have hereby reviewed available tools for tele-neurology examination in MS, including components of neurological examination that can be assessed through video, patient-reported outcome measures (PROMs), and digital technology.

RESULTS

Overall, we have suggested a battery for assessing MS disability and relapses on tele-medicine, which brings together conventional examination, PROMs (e.g., Patient Determined Disease Steps, MS Impact Scale), and cognitive tests (Symbol Digit Modalities Test) that can be delivered remotely and in multiple languages.

DISCUSSION

The use of common tools for neurological examination could improve tele-neurology practice for both general neurologists and MS specialists, and quality of care for people with MS.

Coming off cannabis: a cognitive and magnetic resonance imaging study in patients with multiple sclerosis

Cognitive dysfunction affects 40-80% of patients with multiple sclerosis. Smoking cannabis may add to these deficits. It is unclear whether coming off cannabis results in cognitive improvement. To address this question, 40 patients with multiple sclerosis who started using cannabis after the onset of multiple sclerosis and who used it for at least 4 days a week over many years were divided by odd-even number selection into two groups: cannabis continuation and cannabis withdrawal. Assessments took place at baseline and after 28 days and included serial versions of the Brief Repeatable Neuropsychological Battery for multiple sclerosis containing tests of verbal and visual memory, processing speed and executive function; structural and functional MRI, the latter entailing a compatible version of the Symbol Digit Modalities Test; urine for cannabinoid metabolites to detect compliance with abstinence. Only those participants deemed globally impaired at baseline (failure on at least two cognitive domains) were enrolled. The results revealed that the two groups were well matched demographically and neurologically. One subject was removed from the withdrawal group because of failed abstinence. Urine analysis revealed the cannabinoid consumed was predominantly tetrahydrocannabinol (THC). There were no baseline between group cognitive differences, but by Day 28 the withdrawal group performed significantly better on every cognitive index (P < 0.0001 for all). Significant within group differences were present for every test over time, but only in the abstinent group (P < 0.0001 for all tests). There were no between group baseline or Day 28 differences in structural MRI indices (global atrophy, total T1 and T2 lesion volume). At index assessment the two groups had a similar performance on the functional MRI-compatible Symbol Digit Modalities Test and there were no group differences in brain activation. However, by Day 28, the withdrawal group completed more trials correctly (P < 0.012) and had a faster reaction time (P < 0.002), associated with significantly increased activation in brain regions known to be associated with performance of the test (bilateral inferior frontal gyri, caudate and declive/cerebellum, P < 0.001 for all regions). These results reveal that patients with multiple sclerosis who are frequent, long-term cannabis users can show significant improvements in memory, processing speed and executive function after 28 days of drug abstinence. The absence of similar improvements in a matched multiple sclerosis group that remained on cannabis shows that beneficial cognitive change after stopping cannabis is not solely attributable to the effects of practice.

Brain Amyloid Contribution to Cognitive Dysfunction in Early-Stage Parkinson's Disease: The PPMI Dataset

BACKGROUND

The pathological processes underlying cognitive impairment in Parkinson's disease (PD) are heterogeneous and the contribution of cerebral amyloid deposits is poorly defined, particularly in the early stages of the disease.

OBJECTIVE

To investigate regional [18F]florbetaben binding to amyloid-β (Aβ) and its contribution to cognitive dysfunction in early stage PD.

METHODS

A multicenter cohort of 48 PD patients from the Parkinson's Progression Marker Initiative (PPMI) underwent [18F]florbetaben positron emission tomography (PET) scanning. Clinical features, including demographic characteristics, motor severity, cerebrospinal fluid (CSF), and cognitive testing were systematically assessed according to the PPMI study protocol. For the purpose of this study, we analyzed various neuropsychological tests assessing all cognitive functions.

RESULTS

There were 10/48 (21%) amyloid positive PD patients (PDAβ+). Increased [18F]florbetaben uptake in widespread cortical and subcortical regions was associated with poorer performance on global cognition, as assessed by Montreal Cognitive Assessment (MoCA), and impaired performance on Symbol Digit Modality test (SDMT). Further, we found that PDAβ+ patients had higher CSF total-tau/Aβ1 - 42 (p = 0.001) and phosphorylated-tau/Aβ1 - 42 in (p = 0.002) compared to amyloid-negative PD.

CONCLUSION

These findings suggest that multiple disease processes are associated with PD cognitive impairment and amyloid deposits may be observed already in early stages. However, prevalence of amyloid positivity is in the range of literature age-matched control population. Increased cortical and subcortical amyloid is associated with poor performance in attentive-executive domains while cognitive deficits at MoCA and SDMT may identify amyloid-related dysfunction in early PD.

Test-retest reliability of the Wisconsin Card Sorting Test in people with schizophrenia

PURPOSE

The aim of this study was to examine the test-retest reliability of the Wisconsin Card Sorting Test in people with schizophrenia. In this study, minimal detectable change (MDC) was calculated and systematic measurement errors were evaluated.

METHOD

Sixty-three people with schizophrenia underwent the WCST twice with a two-week interval. Test-retest reliability was evaluated using intraclass correlation coefficient. Systematic measurement error was examined using paired t-test and effect size (Cohen's d).

RESULTS

The values of intraclass correlation coefficient were >0.70, except for two indices ("nonperseverative errors" and "failure to maintain set" with intraclass correlation coefficient of 0.56 and 0.30, respectively). Seven indices showed nonsignificant differences between the two assessments (t(62)= -0.84 to 1.38, p > 0.05) and negligible effect sizes (d = 0.03-0.13). The values of MDC with 95% certainty were 32.3, 42.0, 31.2, 36.9, 40.1, 3.3, and 3.8 for the "total number correct," "perseverative responses," "perseverative errors," "nonperseverative errors," "conceptual level responses," "number of categories completed," and "failure to maintain set" indices, respectively.

CONCLUSIONS

The WCST has acceptable test-retest reliability. Two indices ("nonperseverative errors" and "failure to maintain set") revealed lower levels of consistency in scores over repeated assessments. Clinicians and researchers should be cautious when using these two indices to interpret of the re-assessment results in people with schizophrenia.IMPLICATIONS FOR REHABILITATIONThe Wisconsin Card Sorting Test showed acceptable test-retest reliability in people with schizophrenia.Six indices of the Wisconsin Card Sorting Test revealed substantial random measurement errors, which should be used cautiously to interpret executive functions over repeated assessments.

Prefrontal-Temporal Pathway Mediates the Cross-Modal and Cognitive Reorganization in Sensorineural Hearing Loss With or Without Tinnitus: A Multimodal MRI Study

Objective: Hearing loss, one main risk factor of tinnitus and hyperacusis, is believed to involve significant central functional abnormalities. The recruitment of the auditory cortex in non-auditory sensory and higher-order cognitive processing has been demonstrated in the hearing-deprived brain. The dorsolateral prefrontal cortex (dlPFC), which has dense anatomical connections with the auditory pathway, is known to play a crucial role in multi-sensory integration, auditory regulation, and cognitive processing. This study aimed to verify the role of the dlPFC in the cross-modal reorganization and cognitive participation of the auditory cortex in long-term sensorineural hearing loss (SNHL) by combining functional and structural measurements.

Methods: Thirty five patients with long-term bilateral SNHL and 35 matched healthy controls underwent structural imaging, resting-state functional magnetic resonance imaging (rs-fMRI), diffusion tensor imaging (DTI), and neuropsychological assessments. Ten SNHL patients were with subjective tinnitus.

Results: No differences in gray matter volume, spontaneous neural activity, or diffusion characteristics in the dlPFC were found between the SNHL and control groups. The functional connectivity (FC) between the dlPFC and the auditory cortex and visual areas, such as the cuneus, fusiform, lingual cortex, and calcarine sulcus was increased in patients with SNHL. ANOVA and post hoc tests revealed similar FC alterations in the SNHL patients with and without tinnitus when compared with the normal hearing controls, and SNHL patients with and without tinnitus showed no difference in the dlPFC FC. The FC in the auditory cortex was associated with the symbol digit modality test (SDMT) scores in the SNHL patients, which reflect attentional function, processing speed, and visual working memory. Hearing-related FC with the dlPFC was found in the lingual cortex. A tract-based spatial statistics (TBSS) analysis revealed decreased fractional anisotropy (FA) values, mainly in the temporal inferior fronto-occipital fasciculus (IFOF), which showed remarkable negative correlations with the mean hearing thresholds in SNHL.

Conclusion: Higher functional coupling between the dlPFC and auditory and visual areas, accompanied by decreased FA along the IFOF connecting the frontal cortex and the occipito-temporal area, might mediate cross-modal plasticity via top-down regulation and facilitate the involvement of the auditory cortex in higher-order cognitive processing following long-term SNHL.