Felix H, Johnsson L G, Gleeson M, Pollak A
ENT Department, University Hospital, Zürich, Switzerland.
Acta Otolaryngol Suppl. 1990;470:71-9. doi: 10.3109/00016488909138359.
The myelinated radial fibres in the osseous spiral lamina and the myelinated fibres in the cochlear nerve in the internal auditory canal as well as the sensory cells were counted in cochleae from 15 dissected temporal bones from 8 patients. Light microscopy was carried out on semithin sections of epoxy resin embedded tissue. Audiometry had been performed within 6 months prior to death. Three patients had normal hearing for their age group, 2 had slight presbyacusis and the remaining 3 had sustained noise injury. All specimens clearly had fewer fibres in the spiral lamina than in the internal auditory canal. The cochleae from patients with normal hearing for their age group had a difference in the nerve fibre counts of up to 34%. A case of sensorineural presbyacusis showed 31%, and a case of neural presbyacusis, 47% difference. The greatest difference was found in a case of acoustic trauma, the range in this group being between 25% and 55%. The lower the number of fibres in the spiral lamina, the greater was the difference in all but two specimens. A slow retrograde degeneration, i.e. beginning in the peripheral process of the cochlear nerve, could be an explanation for these findings.
对8例患者的15块颞骨标本的耳蜗进行了研究，计数了骨螺旋板中的有髓放射状纤维、内耳道内耳蜗神经中的有髓纤维以及感觉细胞。对环氧树脂包埋组织的半薄切片进行了光学显微镜检查。在死亡前6个月内进行了听力测定。3例患者听力在其年龄组中正常，2例有轻度老年性耳聋，其余3例有持续性噪声损伤。所有标本的螺旋板中的纤维明显少于内耳道中的纤维。年龄组听力正常的患者的耳蜗神经纤维计数差异高达34%。1例感音神经性老年性耳聋病例显示差异为31%，1例神经性老年性耳聋病例差异为47%。在1例声创伤病例中发现差异最大，该组差异范围在25%至55%之间。除2个标本外，螺旋板中的纤维数量越少，差异越大。耳蜗神经外周突开始的缓慢逆行性退变可能是这些发现的一个解释。
