Abstract
Calcium ions are essential for acoustic transmission in the cochlea. The basis of the calcium metabolism and transport in the cochlea was discussed, and both experimental and clinical evidences that the systemic disturbance in calcium and vitamin D (V. D) induced the cochlear dysfunction were shown. The long-term decrease in the calcium concentration in serum reduced that in perilymph. The N1 response was damaged by the perilymphatic perfusion with low-calcium solution.
The hearing impairment was observed in the V. D deficient rat. On the basis of the abovementioned findings, the cochlear dysfunction associated with hypoparathyroidism might be brought about by the metabolic disturbance of calcium in the inner ear fluid secondary to the decrease in serum calcium and/or the direct effect of the decreased V. D upon the cochlea. The latter was supported by the fact that the low level of serum V. D was commonly observed in patients with bilateral sensorineural hearing loss.
