Endolymph, a unique extracellular fluid in the cochlea of the inner ear, exhibits a highly positive potential of +80 mV. This so-called endocochlear potential (EP), which is indispensable for hearing, originates from the lateral cochlear wall. The lateral wall, which comprises the stria vascularis and its neighboring spiral ligament, is likely made up of two epithelial layers. By using electrophysiological and theoretical approaches, we have shown that the EP depends on the K+ dynamics in the extra/intracellular compartments of the lateral wall. Of importance, the K+ environment seems to be controlled by the unidirectional K+ transport throughout the cochlea. Moreover, the results of our recent study suggest that of the several K+-transport molecules expressed in the lateral wall, only Na+, K+-ATPase is likely to be involved in driving the unidirectional K+ transport. These findings will contribute not only to elucidation of the mechanism underlying hearing, but also that of the pathophysiological processes involved in deafness caused by impairment of the EP.
In order to evaluate hearing loss in elderly people, we recorded and compared the pure-tone threshold and speech discrimination scores in 399 ears. The subjects were 201 males and 198 females with sensorineural hearing loss; the patients were seen between 2007 and 2014 and ranged in age from 6 to 96 years. The pure-tone audiogram showed decline of the threshold after the age of forty, and the maximum score in the speech audiogram became worse after the age of sixty years. While the pure-tone threshold showed a large dispersion in younger patients, the discrimination scores were poor and widely spread dispersed in the elderly.
These two auditory tests are psychological methods and depend to some extent on the sensitivity of the aging patients. The difference between the two tests seems to be that the pure-tone test reflects the function of the cochlea per se, while the speech discrimination test reflects the cochlear nerve activity. While presbycusis is characterized by abnormalities at both levels, the ages of onset differ. Therefore, two tests should be coupled and carefully studied together for evaluating the hearing problems associated with aging.
A total of 87 users of a long-term care health facility underwent ear examinations and audiometry. The average age of the subjects was 83.5±8.0 years and the average score on the Mini Mental State Examination (MMSE) was 14±9.0. In the subjects who could not react with the button in the hearing test, other methods such as placing marbles, raising a hand, or verbal response were used. Behavioral observation audiometry was also used in some subjects. The subjects were divided into four groups according to the reliability of the hearing test. We investigated the MMSE scores and the timing of the hearing test in the four groups.
Ear examination showed normal results in 64 subjects (73%). In all of the 17 cases (100%) with MMSE scores of 24 and over, the right and left hearing thresholds were measurable by using several reaction patterns according to the cognitive function level of the subjects. Furthermore, they were also measurable in 30 of the 33 cases with MMSE scores of 11-23 (91%), and 12 of the 31 cases with MMSE scores of 10 or lower (38%). Bilateral hearing loss was observed in 56 (90%) of the 62 subjects in whom the audiometry threshold could be obtained. There was no statistically significant correlation between the hearing level and the MMSE scores.
Objective: To obtain basic data for appropriate intervention in elderly persons requiring nursing care with hearing loss.
Subjects: A total of 87 elderly persons requiring nursing care admitted to a single long-term care facility (38 men, 49 women; mean age, 83.5±8.0 years).
Methods: A questionnaire on hearing loss recognition and expressions used daily was administered to the nursing staff principally involved in the care of these subjects. Based on the average hearing level of the good ear, the subjects were classified as having normal hearing or as having mild (≥25dB), mild-moderate (≥40dB), moderate (≥50dB), or severe (≥70dB) hearing loss, with no threshold (severe dementia, no response on evaluation), and the relationship between questionnaire responses and the hearing level was analyzed.
Results: Nursing staff reported recognizable differences in the elderly patients' behaviors according to the hearing level. A significantly higher proportion of the≥40dB group requested repetition in a quiet place and revealed hearing difficulty. Expressions used by the nursing staff differed depending on the hearing level.
Discussion: In order to evaluate and correct the hearing in elderly persons requiring nursing care, otorhinolarygologists and speech-language-hearing therapists should work together with the nursing staff, sharing information on hearing loss recognition.
Our facility was inaugurated in June 2014 as a clinic that provides specialized outpatient treatment for patients with hearing impairment and delayed language acquisition, in addition to conducting general practice for ear, nose, and throat ailments. In this report, we analyzed the hearing aid fitting status and post-purchase course of 94 elderly hearing-impaired subjects who visited our clinic for hearing aid consultation between June 2014 and June 2015. The mean age of the subjects was 78.4 years old (±3.5). Of the 94 subjects, 71 purchased hearing aids, while the remaining 23 cases did not. In the group that bought hearing aids, the mean hearing level of the better hearing ears was 52.1 dB (±6.3) (method of quartering), the mean unaided speech discrimination score in the 57-S Japanese monosyllable test was 61.6% (±15.7), and the mean aided speech recognition score improved to 70.1% (±4.4). In the group that did not purchase hearing aids, the mean hearing level of the better hearing ears was 48.6 dB (±5.3) (method of quartering), and the mean unaided speech discrimination score in the 57-S Japanese monosyllable test was 67.1% (±10.7). Thus, there were no significant differences in the audiometric characteristics between the two groups.
On the other hand, the group that purchased hearing aids showed lower scores in the subjective evaluation by “the Questionnaire on hearing 2002” than the group that did not purchase hearing aids.
The common reason for purchasing hearing aids was to improve speech understanding in the hobby. For each patient to use their hearing aids regularly, guidance on the wearing of hearing aids and fine-adjustment of the hearing aids were performed frequently, which, on average, required approximately six consultations. In addition, we evaluated the patients' status of wearing hearing aids after the purchase of the hearing aids using “the Questionnaire on hearing 2002 for Fitting”. After three months of wearing the hearing aids, the duration and the situation of hearing aid usage improved. In hearing aid fitting for seniors, utilization of hearing with hearing aids might be improved by providing regular guidance after the purchase.