Grip-strength, fatigue, and motor perseveration in anxious men without depression.

Objective: To investigate the influence of anxiety without depression on functional motor asymmetry in adult men. Thus, left-and right-hand grip strength, fatigue across trials, and motor perseveration was examined among 60 right-handed men, half of whom had been classified as anxious without depression (HI, n = 30) and the other half as nonanxious without depression (LO, n = 30).

Background: There is substantial empirical support for the notion that individuals with negative affect experience relative right anterior activity. Moreover, previous studies using other groups of interest (e.g., depression and hostility) have found evidence of functional motor asymmetry that is supportive of relative right anterior activation during negative affect. Less is known about functional motor asymmetry among individuals that report anxiety without depression.

Method: To obtain indices of perseveration, strength, and fatigue, HI and LO anxious subjects were asked to successively squeeze a hand dynamometer. Dependent measures (in kg) were derived from performance with the left and right hands across trials.

Results: In contrast to LO anxious subjects, HI anxious subjects did not demonstrate right-hand superiority for grip-strength. Moreover, significant positive correlations existed between grip strength and trait anxiety scores for LO anxious subjects, but not for HI anxious subjects.

Conclusions: The data are partially supportive of differences in functional motor asymmetry between HI and LO anxious individuals. The findings are interpreted as supportive of relative right anterior activity (and possibly decreased left anterior activity) among individuals that report elevated levels of anxiety. Implications for relative right-hemisphere activity and decreased left anterior activity are discussed, and alternative explanations are introduced.