Total amount learned versus learning rate of verbal and nonverbal information, in differentiating left-from right-brain injured patients

Twenty Left-Brain Damaged (LBD), 20 Right-Brain Damaged (RBD), and 20 control subjects were compared on three different learning tasks: (a) verbal, the Paired Associate Learning subtest of the Wechsler Memory Scale; (b) figural, the Gollin Incomplete Figures task, which can be easily verbalized, and (c) spatial, the Stylus Maze. When learning ability was measured, by assessing the total amount learned (sum of items learned in all trials), the results showed that, on all three tasks, the control group's performance significantly surpassed that of the patient groups. The RBD group performed better than the LBD group on the verbal learning task, while LBD subjects performed better than their RBD counterparts on the spatial learning task. No significant difference between the two patient groups was detected on the figural task, suggesting that a task using visually and verbally codable stimuli is not useful in differentiating between LBD and RBD groups. When the learning rate was measured, similar results were obtained in the verbal and figural task. However, in the spatial task, the learning rates of the three groups did not significantly differ, probably because the specific task used required procedural learning, which is normally preserved in amnesics.