進行性筋萎縮性疾患における聴覚障害について

HEARING IMPAIREMENT IN CASES OF PROGRESSIVE MUSCLE ATROPHIC DISEASES

　進行性に筋肉の萎縮をおこす疾患は，大きくわけると，神経性，筋原性のものとがある。とくに耳鼻咽喉科領域においては，顔面筋，咽頭筋，舌筋などの萎縮による構音障害，声帯筋萎縮による声域障害についても問題になるがこれらの報告は少ない。これらの患者の聴力についての研究はさらに少ない。とくに神経性に筋萎縮をおこす疾患にともなう難聴についての論文は2〜3あるが，筋原性に筋萎縮をおこす疾患にともなう難聴についての報告はKuhn^1）以外にほとんどない。

　今回われわれは筋原性と考えられている進行性筋萎縮性疾患に難聴をともなつた症例を経験したので，これを報告し，あわせて難聴の病態について考察を加えた。

　Hearing disorders are observed in the cases of progressive muscular atrophic disease.

　In the seven cases of myotonic dystrophy, hearing disorders were found in all cases.

　The types of hearing defect in the cases of progressive muscular dystrophy, appeared to differ with the type of muscular atrophy. In the facioscapulohumeral type of distrophy all three cases had bilateral hearing defect, especially high-tone loss.

　In the Duschene type normal hearing was found in 55 cases out of the 80; 22 cases had unilateral hearing impairement; 24 ears, 19cases, had C⁵ dip; 10 ears, 8 cases, with high-tone loss; and, 8 ears, 7 cases, with low-tone loss.

　In the csaes affected with limb-girdle type, 1 case among the 5 had C⁵ dip.

　In the oculopharyngeal type 2 cases of the 3 had high-tone loss.

　The pathological foci of these hearing impairements might be based in the inner ear because of the findings of recruitment phenomenon and bone conduction disorders.