Faculty Bibliography

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.

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.

Evidence exists demonstrating that infection with hepatitis C virus impairs health-related quality of life, but less is known about the effect of fatigue, a common symptom, on everyday life. The psychometric properties of the fatigue severity scale (FSS) were explored to determine suitability as an outcome measure in clinical trials. The FSS includes nine items developed to measure disabling fatigue and a visual analog scale (VAS) to measure overall fatigue. Using baseline data from three clinical trials (n = 1225) involving chronic hepatitis C patients, scaling and psychometric characteristics of the FSS were assessed. The SF-36 was also used in the trials. Item response theory analysis demonstrated that the FSS items can be placed along a single homogenous domain, fatigue. Internal consistency reliability was 0.94. Test-retest reliability was 0.82 for the total score and 0.80 for the VAS. The total score and the VAS were significantly correlated with the SF-36 vitality subscale (r = -0.76 and r = -0.76 respectively). Correlations with other SF-36 subscales were moderate (r = -0.46 to r = -0.67, all p < 0.0001). In summary, the FSS possesses good psychometric properties.