Speed-accuracy optimization in acquisition of figures after focal cerebral lesion.

Seventy-seven brain damaged patients and 14 control subjects performed a visual memory test in which the subjects had to reproduce geometric figures from memory after studying the design for 10 seconds (standard condition) and after an observation period subjectively necessary and sufficient for accurate reproduction (self-timed condition). The brain damaged patients were less efficient than the control subjects on the self-timed acquisition even when the covariance on the standard condition was taken into account. The prediction that frontal lobe damaged patients are inferior to posterior brain damaged patients on the speed-accuracy optimization of acquisition was true only in the right hemisphere damaged patients on the simple trials, suggesting that right frontal lobe damage disturbs voluntary attention. Visuospatial errors were typical for right hemisphere damaged patients, perservations for left frontal lobe damaged patients.