Age differences in hemispheric activation to sensory condition

The effects of combinations of bright or dim light and noise levels on hand strength, fatigue, motor perseveration, and tapping rate were evaluated in 13 undergraduate and 13 elderly females. Increments in the intensity of sensory conditions produced opposite effects on grip strength at the left, as opposed to the right hand. Reliable asymmetry in hand strength (right > left) was observed in bright but not dim lighting in the younger group. In the elderly group, the extent of asymmetrical hand strength was related to the combination of light and noise intensity. Data suggest that increments in sensory conditions may differentially activate the cerebral hemispheres of the elderly and younger groups affecting grip strength. Results are discussed in relation to the hemiaging hypothesis.