ABSTRACT
OBJECTIVE: Cognitive impairment is a common symptom of multiple sclerosis (MS). The present study aimed to assess fatigue-related diurnal variations of cognitive performance in MS patients. METHOD: Subjective cognitive fatigue and cognitive performance in three reaction time tasks differing in cognitive demands (alertness, Go/NoGo, divided attention) was measured at three different times of day on two consecutive days for MS patients, stroke patients, and healthy control participants. RESULTS: Objective measures of cognitive performance revealed poorer performance for both groups of patients than for controls. A diurnal decline of cognitive performance was only observed for the two groups of patients but not for healthy controls. This decline corresponded to the patients' subjective reports of increasing cognitive fatigue during the day. CONCLUSION: Cognitive fatigue in both MS and stroke patients is not only reflected in subjective ratings but also affects objectively measured performance in cognitive tasks.
Subject(s)
Circadian Rhythm/physiology , Cognition Disorders/etiology , Fatigue/etiology , Multiple Sclerosis/complications , Stroke/complications , Adult , Analysis of Variance , Attention Deficit Disorder with Hyperactivity/etiology , Decision Making/physiology , Fatigue/psychology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Reaction Time/physiology , Young AdultABSTRACT
Functional neuroimaging may provide insights into the achievement gap in reading skill commonly observed across socioeconomic status (SES). Brain activation during reading tasks is known to be associated with individual differences in children's phonological language skills. By selecting children of equivalent phonological skill, yet diverse socioeconomic backgrounds, we use functional magnetic resonance imaging (fMRI) to demonstrate that a child's experience, as operationalized by SES, can systematically modulate the relationship between phonological language skills and reading-related brain activity in left fusiform and perisylvian regions. Specifically, at lower socioeconomic levels, individual differences in skill result in large differences in brain activation. In contrast, as SES increases, this relationship between phonological language skill and activation is attenuated. Socioeconomic background factors are thus found to modulate brain-behavior relationships in reading, indicating that cognitive, social, and neurobiological influences on reading development are fundamentally intertwined.
