Motor Cortex Preactivation by Standing Facilitates Word Retrieval in Aphasia

Abstract

Background and Objectives. A tight link between linguistic functions and activation of motor areas has been consistently reported, indicating that the 2 systems share functional neural resources. Few efforts have been made to explore whether this knowledge could aid the rehabilitation of aphasia. Methods. The authors assessed whether preactivation of the leg motor cortex during standing, compared with sitting, can facilitate language production in patients with chronic aphasia. In a cross-over within-subject design, the authors assessed performance on a picture naming task and controlled for effects on processing speed and simple verbal reaction time. Results. They found that standing compared with sitting had a beneficial effect on the number of semantic self-corrections that resulted in correct naming. In the absence of effects on motor or general processing speed, this points to a specific effect on lexical retrieval and selection. This was further corroborated by an error pattern analysis. Successful semantic self-corrections during standing were only found when there was already partial activation of the target semantic network—that is, when self-corrections were preceded by an incorrect but semantically associated naming response. Discussion. These findings show that preactivation of the motor system, which extends beyond the intrinsic link between manual gestures and language, can facilitate lexical access in chronic aphasia and may open new directions in aphasia rehabilitation.