Assessment of cognitive functions in patients with multiple sclerosis

Background About 40–70% of patients with multiple sclerosis (MS) develop cognitive impairment (CI) throughout their life. We aim to study the influence of MS on cognitive changes. This is a case–control study of fifty patients with MS who met the revised 2017 Mc Donald Criteria and fifty age- and sex-matched healthy subjects. The Expanded Disability Status Scale (EDSS) was used to assess the degree of disability, and the Montreal Cognitive Assessment (MoCA) scoring system was used to assess cognitive function. Results MS patients show low total MoCA score than the controls. Total MoCA scores were lower in patients with CI versus those with intact cognition. CI was higher in those with a longer duration of illness and a high EDSS. MoCA was positively correlated with education level but negatively with EDSS and disease duration. Conclusion MoCA scale has optimal psychometric properties for routine clinical use in patients with MS, even in those with mild functional disability. The longer the disease duration and the higher the EDSS, the lower the MoCA score and the higher the education level, the higher the MoCA score. As for the profile of cognitive dysfunction in patients with MS, the domains most frequently failed by the patients were memory, attention, visuospatial learning, and language.

Use of wearable physiological sensors to predict cognitive workload in a visuospatial learning task

BACKGROUND: Increased cognitive workload, sometimes known as mental strain or mental effort, has been associated with reduced performance. OBJECTIVE: The use of physiological monitoring was investigated to predict cognitive workload and performance. METHODS: Twenty-one participants completed a 10-minute seated rest, a visuospatial learning task modeled after crane operation, and the Stroop test, an assessment that measures cognitive interference. Heart rate, heart rate variability, electrodermal activity, skin temperature, and electromyographic activity were collected. RESULTS: It was found that participants’ ability to learn the simulated crane operation task was inversely correlated with self-reported frustration. Significant changes were also found in physiological metrics in the simulation with respect to rest, including an increase in heart rate, electrodermal activity, and trapezius muscle activity; heart rate and muscle activity were also correlated with simulation performance. The relationship between physiological measures and self-reported workload was modeled and it was found that muscle activity and high frequency power, a measure of heart rate variability, were significantly associated with the workload reported. CONCLUSIONS: The findings support the use of physiological monitoring to inform real time decision making (e.g., identifying individuals at risk of injury) or training decisions (e.g., by identifying individuals that may benefit from additional training even when no errors are observed).

Investigating the Residual Effects of Chronic Cannabis Use and Abstinence on Verbal and Visuospatial Learning

Rationale: Regular cannabis users have been shown to differ from non-using controls in learning performance. It is unclear if these differences are specific to distinct domains of learning (verbal, visuospatial), exacerbate with extent of cannabis exposure and dissipate with sustained abstinence.Objective: This study examines different domains of learning (verbal, visuospatial) in current and abstaining cannabis users, and the role of chronicity of use.Methods: In a cross-sectional design, we examined 127 psychiatrically healthy participants (65 female) with mean aged of 34 years. Of these, 69 individuals were current regular cannabis users (mean 15 years use), 12 were former cannabis users abstinent for ~2.5 yrs (after a mean of 16 years use), and 46 were non-cannabis using controls. Groups were compared on verbal learning performance assessed via the California Verbal Learning Test (CVLT-II) and for visuospatial learning measured with the Brown Location Test (BLT). We explored the association between CVLT/BLT performance and cannabis use levels in current and former users.Results: Current cannabis use compared to non-use was associated with worse performance on select aspects of verbal learning (Long Delay Cued Recall) and of visuospatial learning (Retroactive Interference and LD Rotated Recall). Prolonged abstinence was associated with altered verbal learning but intact visuospatial learning. There were non-significant correlations between distinct cannabis use measures, age and learning in both current and former users.Conclusions: Our findings suggest cannabis use status (current use, former use) affects different domains of learning (verbal and visuospatial) in a distinct fashion. These findings might be accounted for in the design of cognitive interventions aimed to support abstinence in cannabis users.

The Forgotten Tract of Vision in Multiple Sclerosis: Vertical Occipital Fasciculus, Its Integrity, and Visuospatial Memory

BackgroundVisual disturbances are a common disease manifestation and a major patient complaint in Multiple Sclerosis (MS) due to lesions damaging white matter tracts involved in vision. Vertical Occipital Fasciculus (VOF) connects ventral and dorsal visual streams and was neglected for more than a century. It has recently become under focus in brain-related disorders. Thus, its role in the visual dysfunction in MS needs to be clarified.ObjectiveEvaluate the integrity of bilateral VOFs in MS and its association with clinical and visual evaluations.Methods56 relapsing-remitting MS (RRMS) and 25 healthy controls (HC) were recruited. We acquired MS Functional Composite, Expanded Disability Status Scale (EDSS), and Brief Visuospatial Memory Test – Revised (BVMT-R), and structural and diffusion MRI scans. After VOF tractography, its integrity markers were statistically tested for between-group differences and clinical and visual tests associations.ResultsRRMS patients had lower fiber integrity in bilateral VOFs compared to HC. Lower integrity of bilateral VOFs was associated with poor clinical outcomes, higher visual score in EDSS, and lower total immediate and delayed recall in BVMT-R.ConclusionVOF damage is seen in RRMS and is associated with visual symptoms and visuospatial learning impairments.

Sex-specific associations between co-exposure to multiple metals and visuospatial learning in early adolescence

The predisposition, severity, and progression of many diseases differ between males and females. Sex-related differences in susceptibility to neurotoxicant exposures may provide insight into the cause of the observed discrepancy. Early adolescence, a period of substantial structural and functional brain changes, may present a critical window of vulnerability to environmental exposures. This study aimed to examine sex-specific associations between co-exposure to multiple metals and visuospatial memory in early adolescence. Manganese (Mn), lead (Pb), chromium (Cr), and copper (Cu) were measured in blood, urine, hair, nails, and saliva of 188 participants (88 girls; 10–14 years of age). Visuospatial memory skills were assessed using a computerized maze task, the virtual radial arm maze (VRAM). Using generalized weighted quantile sum regression, we investigated sex-specific associations between the combined effect of exposure to the metal mixture and visuospatial working memory and determined the contribution of each component to the outcome. The results suggest that sex moderates the association between the metal mixture and visuospatial learning for all outcomes measured. In girls, exposure was associated with slower visuospatial learning and driven by Mn and Cu. In boys, exposure was associated with faster visuospatial learning, and driven by Cr. These results suggest that (a) the effect of metal co-exposure on learning differs in magnitude, and in the direction between sexes, and (b) early adolescence may be a sensitive developmental period for metal exposure.

Acute high-intensity aerobic exercise affects brain-derived neurotrophic factor in mild cognitive impairment: a randomised controlled study

ObjectiveTo investigate the brain-derived neurotrophic factor (BDNF) and cognitive response to a short bout of high-intensity aerobic exercise in older adults with mild cognitive impairment (MCI).MethodsParticipants were randomised to one of two testing schedules, completing either a standardised exercise test (group A) or a resting control condition (group B). Blood sampling and cognitive measures (visuospatial learning and memory, sustained attention and executive function) were collected at baseline (T1) and postintervention (T2). An additional measurement of study outcomes was collected after exercise (T3) in group B only.Results64 participants (female 53.2%, mean age 70.5±6.3 years) with MCI were recruited. From T1 to T2, serum BDNF (sBDNF) concentration increased in group A (n=35) (median (Md) 4564.61±IQR 5737.23 pg/mL to Md 5173.27±5997.54 pg/mL) and decreased in group B (Md 4593.74±9558.29 pg/mL to Md 3974.66±3668.22 pg/mL) (between-group difference p=0.024, effect size r=0.3). The control group made fewer errors on the sustained attention task compared with the exercise group (p=0.025). Measures of visuospatial learning and memory or executive function did not change significantly between groups.ConclusionThis study is the first to show that a short bout of high-intensity aerobic exercise increases peripheral sBDNF in a population with MCI. However, acute exercise did not improve cognitive performance.