Fatigue and depression in brain-injured patients correlated with quadriceps strength and endurance

Many brain-injured (BI) patients complain of persistent fatigue that may alter their lifestyles. In order to assess muscular strength and endurance after brain injury, 22 BI men, greater than 9 months postinjury and aged 20 to 51 years, were separated into two groups based on a complaint of fatigue (fatigue n = 13, nonfatigue n = 9); each performed one maximal isometric knee extension at 60 degrees and 20 maximal isokinetic contractions at 20 rpm using a Cybex II dynamometer. A third group of age-matched, able-bodied men (n = 10) were used as controls. A battery of tests assessing the presence of fatigue (using a symptom checklist and two rating scales), depression, anxiety, and health status were given at the time of isokinetic/isometric testing. The mean fatigue rating, a subjective score, for the fatigue group of BI subjects was significantly worse than the other groups (p less than .01). There was a positive correlation between clinically significant Zung depression scores and fatigue rating (r = .46) and between Zung anxiety scores and fatigue rating. The depression scores for those who complained of fatigue were significantly higher than the other groups (p less than .005). Maximal isometric contractions were no different among the three groups. The mean maximal isokinetic torque during the 20 repetitions was greater in controls than in the BI groups, but did not reach statistical significance (p less than .25). There were no significant declines in isokinetic torque in the 20 repetitions for any of the groups, and the fatigue index was nearly equal for all three groups.(ABSTRACT TRUNCATED AT 250 WORDS)