Because of its high prevalence and implications for quality of life and possibly even disease progression, depression has been intensively studied in multiple sclerosis (MS) over the past 25 years. Despite the publication of numerous excellent empirical research papers on this topic during that time, the publication of theoretical work that attempts to explain depression in a comprehensive way is scarce. In this study, we present a theoretical model that attempts to integrate existing work on depression in MS and provide testable hypotheses for future work. The model suggests that risk for depression begins with the onset of MS. MS results in disease-related changes such as increased lesion burden0brain atrophy and immunological anomalies that are associated with depression in MS, but explain only a relatively limited proportion of the variance. Common sequelae of MS including fatigue, physical disability, cognitive dysfunction, and pain, have all been shown to have an inconsistent or relatively weak relationship to depression in the literature. In the model, we propose that four variables-social support, coping, conceptions of the self and illness, and stress-may moderate the relationship between the above common MS sequelae with depression and help to explain inconsistencies in the literature. (JINS, 2008, 14, 691-724.)

Objective Mental fatigue, a poorly understood symptom of sports-related concussion, ideally requires assessment across multiple modalities. Our study aimed to examine mental fatigue effects among ten neurologically normal, athletically active students undergoing typical concussion testing. It is our intention to ultimately address the question whether fatigue effects due to mild traumatic brain injury (mTBI) may become confounded with fatigue effects due to testing effort. Methods Fourteen athletically active and neurologically normal volunteers were initially recruited from Penn State University. Self-reported fatigue, neuropsychological performance, and electroencephalographic (EEG) activity were measured throughout the whole testing duration. EEG measures in frequency domain (e.g., relative power of theta, alpha & beta bands) were examined over the course of neuropsychological (NP) test administration. Results Predicted fatigue effects over the course of testing included: (a) increased self-reported fatigue; (b) increased errors on the Stroop Interference Test; (c) significantly increased relative power of theta activity during the Stroop Interference Test in frontal-central and parietal regions; and (d) migration of alpha activation from the occipital to anterior (left parietal and pre-central) regions during the Stroop Interference task administered at the beginning compared with the end of testing. Conclusions Results supported predictions related to subjective fatigue and cognitive performance and offered partial support for predictions related to EEG activation patterns over the course of administering the NP testing. Significance Neurologically intact and athletically active college students demonstrate effects related to fatigue after undergoing a typical sports concussion assessment battery, including an increase in subjectively experienced fatigue, a decrease in cognitive task performance accuracy and associated modulations in EEG activity. This finding should be considered by clinical practitioners while evaluating the symptoms of concussion and making a decision regarding the return-to-sport participation.

The present study examined the relationship between the worsening of symptoms across a 3-5-year period of time and self-reported physical activity in a sample of 51 individuals with multiple sclerosis (MS). Of the 51 participants, 35 reported a worsening of symptoms over the 3-5-year period of time. The worsening of symptoms was associated with significantly and moderately lower levels of self-reported physical activity independent of depression and EDSS scores and MS-disease course (P=0.04). This study provides novel evidence that a worsening of symptoms is associated with lower levels of physical activity in individuals with MS.

Although most neuropsychological batteries used with multiple sclerosis (MS) patients now exclude tests that require significant motor writing or manual manipulation speed, many of the most sensitive commonly used cognitive tests nonetheless require some type of rapid oral motor response. The aim of this study is to examine the extent to which primary oral motor articulation speed problems of individuals with MS contribute to performance and group differences on neuropsychological tasks requiring a rapid spoken response. Fifty MS patients and 50 healthy controls were administered the PASAT, COWAT, Animal Naming, and SDMT tests, in addition to a measure of rudimentary oral motor speed known as the maximum repetition rate of syllables and multisyllabic combinations (MRR) task. Regression analyses revealed that the amount of variance accounted for by the group (MS-Control) variable was reduced the following amounts for the tasks when the MRR was entered before the group variable: SDMT, 10% to 6%; PASAT, 4% to 2%; COWAT, 5% to 2%; Animal Naming, 11% to 7%. Our data suggest that rudimentary oral motor speed is slowed in MS patients and makes an important contribution to group differences in performance on commonly used neuropsychological tasks requiring a rapid spoken response. (JINS, 2008, 14, 454-462.)

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