Abstract
A case of slight but persistent articulatory disturbance similar to apraxia of speech caused by infarction of the left putamen and corona radiata is reported. Generally, apraxia of speech and anarthria result from left central gyrus lesions, but some cases have presented symptoms similar to apraxia of speech with left basal ganglia or deep white matter lesions. Therefore we compared symptomatical differences due to a left putaminal lesion with those of a left central gyrus lesion producing apraxia of speech or anarthria, based on previous studies and our case. Two findings were revealed. (1) The main symptom is dysprosody relative to articulatory disturbance if the lesion is confined to the left central gyrus, while the main persistent symptom is articulatory disturbance relative to dysprosody in cases due to deep subcortical lesions including the putamen. (2) No significant basic dissociation of spontaneous-tasked speech impairment could be found between the two lesions. If dissociation exists, spontaneous speech is more impaired than tasked speech such as reading and repetition induced by deep subcortical lesions. We discussed the mechanism of these two findings from neuro-physiological viewpoints including probable lesions and neural compensation pathways. Our study suggests that articulatory disturbance resulting from a lesion of the left central gyrus and that from a subcortical lesion is essentially the same symptom.
