Directional hearing aid benefit in listeners with severe hearing loss

The purpose of this investigation was to examine the potential for directional hearing aid benefit in listeners with severe hearing loss at multiple SNRs for both auditory only and audio-visual presentation modes. Speech recognition performance was measured using the connected speech test at six SNRs individually determined for each subject in order to avoid floor and ceiling effects. The results revealed significant directional benefit was present at all tested SNRs in the presence of visual information. For auditory only presentations, significant directional benefit was only present at the least positive SNR. The largest directional benefit was measured at the poorest tested SNR for both auditory only and audiovisual presentation modes. The results of this study generally support small but significant directional for listeners with severe hearing loss benefit in a difficult listening environment both with and without the presence of visual information.     

Retrocochlear hearing disorders

The diagnosis of retrocochlear hearing impairment is mainly based on threshold tone decay, absence of the stapedius reflex, abnormal dichotic speech discrimination and ERA findings. A relatively poor discrimination for monosyllables with regressive understanding at high intensities can also indicate a neural or central lesion provided that the unaffected side has been correctly masked. ERA results mainly show a synchronisation disorder within the brain-stem, i.e. the J V-response is prolonged or cannot be recorded at all. The cortical response N1, however, corresponds to the subjective threshold except that in impairments of the cortex, the N1-response is worse than expected from the pure tone threshold. Representative examples are given.     

Directional hearing of unilaterally hearing impaired--especially sense of sound direction in monaural hearing impairment and monaural deafness

I. OBJECTIVE. The present study was undertaken in order to determine the onset of monaural deafness, especially whether it is congenital or acquired, making an investigation into the sense of sound direction in monaural hearing impairment and monaural deafness and comparing them between hearing-impaired patients and normal hearers. II. SUBJECTS. This study was carried out on 26 patients with monaural hearing impairment, 22 patients with monaural deafness and 10 normal hearers. III. METHODS. A circle with a radius of 1.3m was drawn around a fixed patient's position in a sound proof room, and the circle was divided into 16 directions at an equal angle of 22.5 degrees. A blindfolded hearer was instructed to listen to a speaker for white noise of 60dB (A) for one second and verbally answer in which direction he heard the noise. The normal hearers were tested in 4-, 8-, and 16-directions, and the hearing-impaired patients were tested in only 8-directions. IV. RESULTS. 1. Normal Hearers The rate of correct answers decreased with increasing directions of sound. The incorrect answers in 4-direction testing were only confusion between forward and backward directions, and similar incorrect answers were made in 8- and 16-direction testing. All other incorrect answers were errors of less than 45 degrees. 2. Monaurally Hearing-impaired Patients The rate of correct answers on the whole was low. There was such a relationship between the rate of correct answers and the mean hearing level of patients that the total rate of correct answers decreased with increasing hearing impairment. This correlation was statistically significant, and there was a still more significant correlation between the degree of hearing impairment and the rate of correct answers as to the right and left directions. Incorrect answers were errors of 90 degrees or less on the healthy side, while errors were made for all directions on the affected side. 3. Monaurally Deaf Patients The rate of correct answers was by far lower on the affected side. Whereas many errors were within 45 degrees on the healthy side, errors were made for all directions on the affected side. Judging from the onset of hearing loss, the monaurally deaf patients were divided into a group of 8 patients who obviously had sudden acquired deafness and a group of 9 patients who were presumed to have congenital monaural deafness. The mean rate of correct answers of the former group was superior to the latter group's, particularly on the effected side.     

Assessment of hearing and hearing disorders in rock/jazz musicians

The aim of this study was to assess hearing and hearing disorders among rock/jazz musicians. One hundred and thirty-nine (43 women and 96 men) musicians participated. The results are based on pure-tone audiometry and questionnaire responses. According to our definition of hearing loss, tinnitus, hyperacusis, distortion and/or diplacusis as hearing disorders, we found disorders in 74%, of the rock/jazz musicians studied. Hearing loss, tinnitus and hyperacusis were most common, and the latter two were found significantly more frequently than in different reference populations. The women showed bilateral, significantly better hearing thresholds at 3-6 kHz than the men. Hyperacusis, and the combination of both hyperacusis and tinnitus, were found to be significantly more frequent among women than among men. Hearing loss and tinnitus were significantly more common among men than among women. It is important to evaluate all kinds of hearing problems (other than hearing loss) in musicians, since they represent an occupational group especially dependent on optimal, functional hearing. On the basis of our results, we suggest that hearing problems such as tinnitus, hyperacusis, distortion and/or diplacusis should, in addition to hearing loss, be defined as hearing disorders.     

Genes related to hearing disorders

The inner ear is a highly specialized organ and the mechanisms of its function are complex and have not yet fully been elucidated. For example, there are questions such as how the stereocilia characteristics of hair cells are regularly arranged, how the reactions of stereocilia and ion channels of hair cells to sound are controlled, and how the ion environment is maintained in the internal ear. The mechanisms of inner ear function are being elucidated by analysis of human hereditary hearing disorders and genetic and molecular biological techniques using mouse hearing disorder models. Understanding of the mechanism of inner ear function provides important information for treatment of the inner ear. This review outlines several findings obtained from humans with hereditary hearing disorders and mouse hearing disorder models.