Multiple Sclerosis Performance Test: validation of self-administered neuroperformance modules

BACKGROUND AND PURPOSE

The purpose was to determine the test-retest reliability, practice effects, convergent validity and sensitivity to multiple sclerosis (MS) disability of neuroperformance subtests from the patient self-administered Multiple Sclerosis Performance Test (MSPT) designed to assess low contrast vision (Contrast Sensitivity Test, CST), upper extremity motor function (Manual Dexterity Test, MDT) and lower extremity motor function (Walking Speed Test, WST) and to introduce the concept of regression-based norms to aid clinical interpretation of performance scores using the MSPT cognition test (Processing Speed Test, PST) as an example.

METHODS

Substudy 1 assessed test-retest reliability, practice effects and convergent validity of the CST, MDT and WST in 30 MS patients and 30 healthy controls. Substudy 2 examined sensitivity to MS disability in over 600 MS patients as part of their routine clinic assessment. Substudy 3 compared performance on the PST in research volunteers and clinical samples.

RESULTS

The CST, MDT and WST were shown to be reliable, valid and sensitive to MS outcomes. Performance was comparable to technician-administered testing. PST performance was poorer in the clinical sample compared with the research volunteer sample.

CONCLUSIONS

The self-administered MSPT neuroperformance modules produce reliable, objective metrics that can be used in clinical practice and support outcomes research. Published studies which require patient voluntary consent may underestimate the rate of cognitive dysfunction observed in a clinical setting.

Executive functions predict weight loss in a medically supervised weight loss programme

Background

Deficits in executive functions are related to poorer weight loss after bariatric surgery; however, less is known about the role that these deficits may play during participation in nonsurgical weight loss programmes. This study examined associations between objectively measured executive functions and weight loss during participation in a medically supervised weight loss programme.

Methods

Twenty‐three adult patients (age 50.4 ± 15.1, BMI 44.2 ± 8.8, 68% female, 92% White) enrolled in a medically supervised weight loss programme, involving prescription of a very low calorie diet and strategies to change eating and activity behaviours, underwent comprehensive computerized testing of executive functions at baseline. Weight was obtained at baseline and 8 weeks. Demographic and clinical information were obtained through medical chart review.

Results

Participants lost an average of 9.8 ± 3.4% of their initial body weight at 8 weeks. Fewer correct responses on a set‐shifting task and faster reaction time on a response inhibition task were associated with lower weight loss percentage at 8 weeks after adjusting for age, education and depressive symptoms. There were no associations between performance on tests of working memory or planning and weight loss.

Conclusions

This study shows that worse performance on a set‐shifting task (indicative of poorer cognitive flexibility) and faster reaction times on a response inhibition test (indicative of higher impulsivity) are associated with lower weight loss among participants in a medically supervised weight loss programme. Pre‐treatment assessment of executive functions may be useful in identifying individuals who may be at risk for suboptimal treatment outcomes. Future research is needed to replicate these findings in larger samples and identify underlying mechanisms.

Uncontrolled eating is associated with reduced executive functioning

Accumulating evidence indicates obesity is associated with reduced cognitive functioning, particularly attention and executive function, as well as maladaptive eating behaviour such as uncontrolled eating. The current study examined relationships between eating patterns and attention/executive function test performance in lean and obese individuals. Sixty-two (32 lean, 30 obese) healthy young adults (21.13 ± 2.31 years; 56.5% female) completed the abbreviated Three-Factor Eating Questionnaire (TFEQ-R18) to assess eating patterns, including uncontrolled eating, cognitive restraint, and emotional eating. The Go/No-Go (GNG), Running Memory Continuous Performance Test (RCMPT) and Standard Continuous Performance Test from the Automated Neuropsychological Assessment Metrics-4 were administered as measures of executive functioning and attention. An independent samples t-test revealed greater report of uncontrolled eating in obese compared with lean participants (t[60] = -2.174, P < 0.05; d = -0.55) but no differences in cognitive restraint or emotional eating. Multivariate analysis of variance revealed cognitive differences between lean and obese groups (F[6, 54] = 3.86, P < 0.005; λ = 0.70; ηp(2) = 0.30), which were driven by GNG reaction time (F[1, 59] = 8.36, P < 0.01, d = 0.74). Pearson bivariate correlations revealed a positive correlation between uncontrolled eating and reaction time on GNG (r = 0.343, P < 0.05) and RMCPT (r = 0.267, P < 0.05) in all participants. Relative to lean participants, obese individuals reported higher levels of uncontrolled eating and exhibited slower performance on a task of inhibitory control. In the full sample, greater self-reported dyscontrol in eating behaviour was related to slower inhibitory control and working memory. Results support a link between executive function and control of eating behaviour. Obese individuals may be more vulnerable to difficulties in these domains relative to those who are lean.