Fatigue in multiple sclerosis compared with chronic fatigue syndrome: A quantitative assessment.
Fatigue, a common complaint among patients with multiple sclerosis (MS), is poorly characterized. We developed a computerized method that quantitatively measures fatigue, and defined a fatigue index (FI), which is the ratio between the integral of muscle strength decay over time and maximal voluntary contraction. Thirty patients (mean age, 37.4 +/- 10.3 years) were examined - 20 patients with pyramidal tract involvement and 10 patients with involvement of other neurological systems. We evaluated 10 patients during relapse and 3 months afterwards, and compared their results with those of four patients with chronic fatigue syndrome (CFS) and 13 age-matched health subjects. The FI was significantly higher in the MS patients as compared with the CFS patients and normal controls: 34.2 +/- 6.4% versus 27.5 +/- 1.0% and 23.6 +/- 6.8%, p < 0.05. Within the MS group, the FI correlated with the presence of pyramidal signs- 43.5% compared with 33% in patients without pyramidal signs, p < 0.01. In MS patients, fatigue worsened during a relapse affecting the pyramidal tract, but not during a relapse in other systems. These results demonstrate that fatigue can be quantitatively measured in MS patients, and that pyramidal dysfunction leads to increased fatigability.
Djaldetti
R
R
Department of Neurology, Beilinson Medical Center, Petah Tiqva 49100, Israel.
Ziv
I
I
Achiron
A
A
Melamed
E
E
D000293:Adolescent; D000328:Adult; D003936:Diagnosis, Computer-Assisted; D005221:Fatigue / Q000209:etiology* / Q000503:physiopathology*; D015673:Fatigue Syndrome, Chronic / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000503:physiopathology; D011712:Pyramidal Tracts / Q000503:physiopathology; D012008:Recurrence; D012016:Reference Values