Damage to the Left Precentral Gyrus Is Associated With Apraxia of Speech in Acute Stroke

Abstract

Background and Purpose-Apraxia of speech (AOS) is a motor speech disorder, which is clinically characterized by the combination of phonemic segmental changes and articulatory distortions. AOS has been believed to arise from impairment in motor speech planning/programming and differentiated from both aphasia and dysarthria. The brain regions associated with AOS are still a matter of debate. The aim of this study was to address this issue in a large number of consecutive acute ischemic stroke patients. Methods-We retrospectively studied 136 patients with isolated nonlacunar infarcts in the left middle cerebral artery territory (70.5±12.9 years old, 79 males). In accordance with speech and language assessments, the patients were classified into the following groups: pure form of AOS (pure AOS), AOS with aphasia (AOS-aphasia), and without AOS (non-AOS). Voxelbased lesion-symptom mapping analysis was performed on T2-weighted images or fluid-attenuated inversion recovery images. Using the Liebermeister method, group-wise comparisons were made between the all AOS (pure AOS plus AOSaphasia) and non-AOS, pure AOS and non-AOS, AOS-aphasia and non-AOS, and pure AOS and AOS-aphasia groups. Results-Of the 136 patients, 22 patients were diagnosed with AOS (7 patients with pure AOS and 15 patients with AOSaphasia). The voxel-based lesion-symptom mapping analysis demonstrated that the brain regions associated with AOS were centered on the left precentral gyrus. Conclusions-Damage to the left precentral gyrus is associated with AOS in acute to subacute stroke patients, suggesting a role of this brain region in motor speech production.

Letter by Terao et al Regarding Article, “Damage to the Left Precentral Gyrus Is Associated With Apraxia of Speech in Acute Stroke”

“…We read with great interest the article by Itabashi et al 1 recently published in Stroke. Using voxel-based lesion-symptom mapping analysis on magnetic resonance imagings of a large number of patients, the authors clearly demonstrated that a restricted area in the left motor cortex is associated with the presentation of apraxia of speech, notably even with that without aphasia.…”

“…Together, it is plausible that this motor area plays an important role in motor speech production. 1 Located in the posterior aspect of the motor cortex, the region may reside in primary motor area (area 4) directly related to motor output, more precisely in the face motor representation (face-M1), rather than in lower motor areas usually implicated in tongue and pharyngeal movements. Indeed, in many of the reports, facial palsy accompanies the impairment in speech motor production.…”

The Prognosis and Recovery of Aphasia Related to Stroke Lesion

“…Meanwhile, involvement of inferior prefrontal gyrus, which plays an important role in semantic processing [1314], and premotor cortex, which is associated with apraxia of speech, may not determine the prognosis of aphasia, but impedes recovery of aphasia [15]. Also, Broca's area is not only associated with poor prognosis, but also with rate or recovery of aphasia.…”

Diagnostic Distortions: A Case Report of Progressive Apraxia of Speech

“…In several patients, this has been associated with marked asymmetry in subcortical perfusion, especially in the left basal ganglia and thalamus, which the authors in one report concluded may be due to an inflammatory basal ganglia dysfunction interrupting basal ganglia-thalamo-cortical connections, including those to the insula [9]. AOS is associated with damage to the left postcentral gyrus in stroke patients, although imaging excluded this diagnosis [10].…”