Abstract
The 5 Japanese vowels in the speech production of Broca's aphasics were analyzed acoustically with a sound spectrograph. The first and second formant frequencies of the speech production among aphasics (3 men, 48, 51, 62 years old, 2 women, 42, 49 years old) and the normals (3 men, 32, 57, 62 years old, 2 women, 32, 46 years old) were compared.
The results are as follows. The variation of the first and second formant frequencies of each case was bigger than that of normals. Especially, in case 5 the relatively acute stage, the variation of the first and second formant frequencies was the most prominent. This phenomenon corresponded with the auditory perception of the distorted sound.
A further sequential experiment on case 5 revealed the decrease of the variation of the first and second formant frequencies. In conclusion, the degrees of the variation of the formant frequencies were different among patients. It was also suggested that the motor programing disorders are found in the articulation of vowels in these cases.
