[Spontaneous speech disturbances in so called transcortical motor aphasia--comparison of 3 cases with the different lesion sites].

So called transcortical motor aphasia (TCMA) is frequently subdivided, because the clinical features and the localization of the lesions are variable. The authors have been attempting to classify TCMA into three types according to the distribution of the lesions, such as Type F 1, Type F 2 and Type F 3. Case 1 N.S. belongs to Type F 1 showing the clinical features of TCMA with bleeding in the territory of the left anterior cerebral artery. Case 2 M.E. belongs to Type F 2 (published case). This case is similar to Luria's dynamic aphasia in its clinical features and results from the lesions including the posterior parts of left middle frontal gyrus. Case 3 N.T. belongs to Type F 3 who recovered from typical Broca aphasia after language training for four years. The case is similar to Goldstein's Type 1 of TCMA in its clinical features. These three cases are compared with regard to the fundamental bases of spontaneous speech disturbance. The items of comparison are as follows; the volume of speech production and the the time taken to start speech, word fluency test, cue effects necessary for the success of sentence constructions grammatical ability. The results are summerized in Table 2. Type F1 shows the most conspicuous defect of spontaneous speech, but no disturbance in grammatical ability. And when the top word of a sentence (a subject word) is given by the examiner, the patient can construct a structurally correct sentence. These findings imply that the spontaneous speech disturbance of Type F 1 is due to a defect of the starting mechanism of speech.(ABSTRACT TRUNCATED AT 250 WORDS)