Characteristics of the bimanual deficit using grip strength

Grip strength was used to evaluate bimanual functioning and the bimanual deficit as a measure of the relationship between the hands and the hemispheres. Participants were 174 right-handed individuals. Experiment 1 measured maximal, unimanual, and bimanual grips. There were two bimanual, simultaneous grip conditions: (1) symmetrical (hands perform the same grip) and (2) asymmetrical (different grips for each hand). Decrements were equivalent for preferred and nonpreferred hands and were similar for males and females. Experiment 2 consisted of three variations of the bimanual, asymmetrical grip condition used in Experiment 1. Emphasis was imposed on a single hand via a performance criterion and feedback. Results indicated that emphasis imposed on either hand produced a strength increment compared to that hand's baseline, but did not affect the concurrently performing hand. Results suggest that the bimanual coordination is governed at a non-lateralised or inter-hemispheric level for both males and females.