[Analysis of improper pattern of Mandarin monosyllable recognition test among the patients with auditory neuropathy]

To analyze the improper pattern in mandarin monosyllable recognition test among the patients with Auditory Neuropathy (AN) in order to work out the common characteristics in speech recognition which might be suitable for diagnosis of AN.

Sixteen AN patients (32 ears) were studied and 22 patients (32 ears) with sensorineural hearing loss (SNHL) were set for control. In accordance with audiogram pattern, all subjects were then divided into the up-type hearing (15 ears) and non up-type hearing (17 ears) groups. All 64 ears were tested in high intensity by mandarin monosyllable test material which we have developed before. Monosyllable performance scores from testing ears and improper patterns were recorded respectively. Eight improper patterns were then defined as follows: consonant only, vowel only, tone only, consonant and vowel, consonant and tone, vowel and tone, all phonemes and no response.

The score of patients with AN was lower than those patients with SNHL in monosyllable recognition test (P < 0.001). No significant difference was found between subgroup of up-type hearing loss and SNHL group in percentage correct scores of monosyllables, consonants, vowels, and tones statistically (P > 0.05), but significant lower score was found in subgroup of non up-type hearing loss compared with SNHL group in these 4 percentage scores concerned (P < 0.001). Chi square test presented a significant difference in improper pattern proportion between AN and SNHL groups (P < 0.001), which could be related to more proportional tone recognition in the former's incorrect items. Improper pattern proportions between two AN subgroups presented a significant difference statistically (P < 0.001), which could be related to a larger proportional recognition of tones and vowels in subgroup of up-type hearing loss compared with subgroup of non up-type hearing loss.

A poor performance might be a major clinical feature identified AN from SNHL in mandarin tone recognition. There are significant differences between AN patients with up-type hearing loss and patients with non up-type hearing loss in performance of monosyllable recognition and improper pattern proportion of tones and vowels. A psychophysical testing may be a key potential in diagnosis of AN in further clinical application.