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Biomedical subjects

Y N Mehra

Publications and source records attributed to Y N Mehra.

44 records · Page 3Linked to original sources

Electrical response audiometry (ERA) in infants.

The electric response audiometry is a useful diagnostic technique for identifying hearing loss in infants. Among the various electrical responses, the BSER enables us to arrive at an accurate early clinical diagnosis of hearing loss in infants so that effective auditory input, which is the prime requisite for the conceptual foundation for the growth of communication, can be provided through appropriate intervention programmes. The electric response audiometry provides information regarding the physiologic state of the peripheral organs and auditory pathways but however, cannot ascertain whether the infant can hear, in terms of perceiving auditory information. Inspite of this major limitation, the growing acceptance of brainstem electrical potentials in clinics and laboratories throughout the world attests to their increasing importance especially in the assessment of hearing sensitivity of infants.

Audiometry, Evoked Response↗

Auditory investigations in hypothyroidism.

Twenty patients with thyroprivic hypothyroidism with a mean age of 34.8 years (range: 15-50 years) were investigated. Peripheral/central functions of the auditory system were assessed in the hypothyroid state and they were re-evaluated in the euthyroid state after treatment with levothyroxine. The mean observation period for re-evaluation was 3.7 months (range 3-7 months). Sixteen patients with hypothyroidism (80%) demonstrated hearing loss when compared with randomly selected age- and sex-matched normal subjects. Twelve of the hypothyroid patients had sensorineural hearing loss and 4 had mixed loss. Special hearing tests revealed a cochlear type of hearing loss. The tympanogram curve was of Type B in one ear of each of the 4 patients. Brainstem electric response audiometry showed prolonged, absolute latency of wave V and interpeak latencies I-III and I-V. The amplitudes of waves I, II and V were reduced. Following treatment with levothyroxine a statistically significant improvement in hearing thresholds was observed by pure-tone audiometry. Tympanogram curves returned to normal in 3 out of 4 patients. Brainstem electric response parameters did not show significant reversibility to normalcy following treatment. The results of auditory investigations suggest a causal relationship between hypothyroidism and hearing loss. The site of lesion in the auditory system is probably at several levels, viz. in the middle ear, and at cochlear and retrocochlear sites.

Acoustic Impedance Tests↗

Eighth nerve evaluation in leprosy.

25 cases of bacillary positive leprosy patients and 25 age and sex matched controls were investigated for assessment of cochleo-vestibular status. Impaired hearing was complained of by 4 patients. None had tinnitus, dizziness or vertigo. On testing 44% patients were found to have unilateral or bilateral perceptive deafness. Specialised tests of hearing indicated that the deafness was of cochlear type. The vestibular functions were not affected. Leprosy seems to selectively involve the cochlea.

Adult↗