Acute low-tone sensorineural hearing loss (ALHL) appears to be one of the relatively common otologic disorders that rather frequently encountered in clinical practice. It is characterized clinically by the features that: 1) the onset is acute or sudden, 2) the etiology remains obscure, 3) the hearing loss is strictly sensorineural in nature, restricted to the low frequency range (125, 250 and 500 Hz), and usually unilateral.
We retrospectivelystudied 127 patients with this disorder over a period of 6 years and 8 months and comparedwith 105 patients with sudden deafness (SD) who were treated at our clinic during a similar time span. It was found that there was a marked sex predominance for females (male-female ratio=37: 90) and that it occurred in rather younger population as compared with sudden deafness. As for the prognosis, most patients of ALHL showed a hearing recovery more rapidly than sudden deafness. Younger individuals with this disorder frequently showed hypotension and positive Schellong's test results. Interestingly, in two cases of SD their audiometric configuration coincided well with ALHL diagnostic criteria during their clinical course. Thus, it may be speculated that there are some common pathognomonic conditions or factors in the auditory system to provoke both ALHL and sudden deafness, although the clinicalfeatures quite differ from each other.
