急性CO中毒症例の濾波語音両耳聴検査成績を中心として

抄録

The severe acute CO-poisoning series among the hundreds sufferers of the last great industrial accident at the "M" Coal Mine have been treated in the Kyushu University Hospital for over 2 years.
We had an opportunity, rarely to be experienced, to perform the binaural articulation testing method wit filtered speech sounds against these 17 patients of CO-poisoning anamnesis.
They showed various findings in neurological and variegated cerebropathological signs, the latter being amnesia of fixation, sensory aphasia, agnosia, agraphia, dementia of various degrees, emotional deterioration, and unsteadiness of feeling. They showed also abnormal EEGs. Three cases had tinnitus soon after the accident and one case after 6 months. Except these four cases, no hearing disorder complaints were made. There were 12 ears with cs dip in 8 cases. With the exception of certain cases which showed a slight hearing loss in high frequency range, the average hearing loss of the main speech frequency range in the majority was measured within normal limits.
The normal control value of the binaural lowand high-pass articulation at the speech intensity level of 60 dB was 60%.
The filtered speech sounds of our equipment consists in a steep elimination of the frequency range between 850- and 3400-cps. Nine cases of the CO-poisoning series, the majority of the total observed cases, however, showed values below 50 %. Four cases were 60-80%. Furthermore, inspite of excellent hearing ability for high tones, the articulation score of the binaural test with filtered speech sounds was remarkably poor, 30% in 2 other cases.
The reason why they showed such remarkably diminished values of articulation test by filtered speech sounds in spite of their results of the binaural articulation test with overall passed speech sounds, should be found in the disorder of the central auditory pass way above mesencephalon, especially at the involvement of the connecting fibers of corpus callosum caused by CO-intoxication-, which participate in role of central fusion to complete the projected sound images from both ears.