Oral form identification as a measure of cortical sensory dysfunction in apraxia of speech and aphasia

Oral form identification scores were obtained for nine anterior and nine posterior left-hemisphere brain lesion subjects exhibiting speech apraxic behavior and aphasia. An objective measure of speech apraxic difficulty and a standardized aphasia assessment were obtained for each subject. Despite the traditional association of a cortical sensory deficit including asterognosis in posterior brain-injured patients, oral form identification scores did not differ significantly for the two subject groups. However, a previously reported heterogeneity of performance was observed in the present data. The oral form identification deficit was unrelated to the severity of apraxia but exhibited its highest correlation value with a task of linguistic symbol discrimination. Results were interpreted to suggest that oral form identification deficits are most probably not causally related to motor speech programming problems nor should such deficits in this population be viewed as a valid indicator of cortical sensory dysfunction.