Faculty Bibliography

Fatigue is among the most common, yet least understood, symptoms of multiple sclerosis (MS) [1.]. It can profoundly disrupt the occupational and social functioning of patients, and is recognized as a criterion for MS disability by the Social Security Administration. Most approaches to fatigue assessment can be classified as either self-report scales or performance-based measures of motor or cognitive output. During the clinical management of fatigue, it is important to consider the role of other MS symptoms on fatigue, as well as that of non-MS-related medical conditions. Management of fatigue in MS often entails both pharmacologic and behavioral components. This article reviews recent developments in the assessment, treatment, and pathogenesis of MS fatigue.

Recent studies have demonstrated the utility of magnetic resonance (MR) spectroscopic imaging to evaluate axonal integrity in patients with multiple sclerosis (MS). Patient status in MS is frequently assessed by the Expanded Disability Status Scale, which emphasizes ambulation but underestimates the contribution of cognitive factors. Yet, cognitive functions of memory and processing are known to be impaired in MS. We used quantitative MR spectroscopy to determine this relation between cognitive function and N-acetyl aspartate (NAA) levels. We find a significant correlation (r = .63, p < .005) for the left periventricular (PV) NAA concentrations with performance on the verbal Selective Reminding Test. Right PVNAA was significantly (p < .02) correlated with the Tower of Hanoi performance, with r = .58.

The authors used data collected prospectively during a multicenter trial in 133 patients with secondary progressive MS to assess the relative sensitivity of quantitative functional tests and traditional measures, including the Expanded Disability Status Scale (EDSS) and Ambulation Index. Quantitative functional measures worsened in 69% of patients during an average of 6 months of observation, whereas the Clinical Global Impression of Change worsened in 33% and the EDSS worsened in 25% of patients. These changes should be interpreted in the context of the test-retest reliability for each measure.