Abstract

Multiple sclerosis (MS) is the most common neurological disorder of young adulthood and is often associated with cognitive impairment and emotional dysfunction. Due to the nature of the disease, the cognitive deficits in MS are often variable in their presentation, and consist of deficits in processing speed, attention, working memory, and executive functioning. The purpose of the present study was to explore common methods of documenting MS-related cognitive deficits, to elucidate the relationship between the cognitive deficits seen in MS and physiological markers of cognitive functioning (i.e., quantitative EEG), and to analyze the relationship between cognitive deficits and mood dysfunction in MS. There were 26 participants diagnosed with remitting-relapsing multiple sclerosis and 18 age, sex, and education matched controls. Results of cognitive testing indicated deficits in gross cognitive functioning, language, attention, processing speed, working memory, and executive functioning. A MANOVA encompassing group, task (PASAT and SPT) and load (light and heavy) showed significant group and load effects, but no main effect of task. The MS group performed worse than the controls and both groups performed better on the light load than the heavy load. Post hoc analysis indicated that performance on the PASAT 3 second trial was worse than on the PASAT 2 second trail compared to controls. Given that the PASAT 3 trial is theoretically easier than the PASAT 2 trial and that the PASAT 3 was administered first, the above results likely reflect learning effects. A Repeated Measures ANCOVA encompassing EEG and cognitive data (PASAT and SPT) indicated group-level differences on task performance, and suggested that at rest mean peak alpha frequency (PAF) is associated with performance on the PASAT, but not the SPT. EEG coherence during cognitive tasks was reduced between short-range connections in the theta, alpha, and beta frequency bins and enhanced in a limited number of long-range, anterior to posterior connections in the theta frequency bin in the MS group compared to controls. Finally, the MS participants had significantly more symptoms of depression and anxiety compared to normal controls. A hierarchical multiple regression analysis suggested that cognitive functioning is deleteriously affected by depression and anxiety. Overall, the results of this study substantiate the feasibility of utilizing QEEG as a physiological indicator of cognitive and cortical dysfunction in MS and show the importance of recognizing depression and anxiety and their contributions to cognitive deficits in individuals with MS.

Degree

PhD

College and Department

Family, Home, and Social Sciences; Psychology

Rights

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