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

Gary C. Walker, Diana D. Cardenas, Mark R. Guthrie, Alvin McLean, Marvin M. Brooke

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Many brain-injúred (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, >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° and 20 maximal isokinetic contractions at 20rpm 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<.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 < .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 < .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. Despite the difference in fatigue complaint and an accompanying increase in depression, there was no difference in isometric or isokinetic strength among BI subjects. Possible explanations for the small, not statistically significant, decrease in isokinetic strength in all BI subjects might include deconditioning, incoordination, inability to concentrate, spasticity, or motor unit recruitment abnormalities.

Original languageEnglish (US)
Pages (from-to)469-472
Number of pages4
JournalArchives of physical medicine and rehabilitation
Issue number7
StatePublished - Jun 1991


  • Brain injury
  • Depression
  • Fatigue
  • Strength

ASJC Scopus subject areas

  • Rehabilitation


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