Neurodegenerative Disease (e.g. MS, Parkinson's disease)
Neuroplasticity (includes neuroscience)
This workshop will compare cognitive workload and performance in cognitive tasks as two different constructs of cognitive functioning in multiple sclerosis.
Cognitive workload is operationally defined as the mental effort needed to complete a cognitive task. The Index of Cognitive Activity (ICA) is a measure of cognitive workload derived from changes in pupil size. The aim of this study was to compare cognitive workload, indexed by ICA, between individuals with multiple sclerosis (MS) and controls.
Design : Prospective, cross-sectional comparison study
Setting : University Hospital
Participants (or Animals, Specimens, Cadavers) : 22 participants with MS (age, mean ± SD), 48.45 ± 10.75; 14 women) with Expanded Disability Rating Scale scores ranging between 1 and 8, and 22 control participants (age, 44.95 ± 11.05; 16 women).
Main Outcome Measure(s) : Peak ICA value (range between 0 and 1), reflecting maximum cognitive workload during cognitive tasks, was the main outcome measure. Secondary outcome measures included behavioral performance on the Stroop Color, Word, and Interference tests, Trail Making Tests (TMT) A and B, and Brief International Cognitive Assessment for Multiple Sclerosis.
Results : Participants with MS made more errors on the Stroop Interference test compared to controls (1.86 ± 7.66 vs 0.05 ± 0.21, p = 0.04). Similarly, they showed greater peak ICA values in the left (0.77 ± 0.07 vs 0.73 ± 0.11, p = 0.06) and right eye (0.74 ±0.08 vs 0.70 ± 0.12, p = 0.045). They also took longer to complete TMT B (46.56 ± 38.79 vs 26.70 ± 8.36, p<0.0001), and showed greater peak ICA values in the left eye (0.72 ± 0.08 vs 0.70 ± 0.13, p = 0.02). No other significant differences were found in ICA values between groups.
Individuals with MS exert greater cognitive workload to complete executive speed of processing tasks, despite poorer behavioral performance on these tasks. Further analysis is needed whether pupillary responses can assist in diagnosing cognitive impairments in MS.