History Of Hearing Impairment Research Articles

Is there a relationship between U-shaped audiograms and mutations in connexin 26?

The knowledge about gene mutations causing permanent hearing impairment (HI) is rapidly increasing, offering clinicians the possibility of analysing different gene mutations in relation to various phenotypes. This study examines a possible relationship between U-shaped audiograms and mutations in the GJB2-gene, coding for Connexin 26 (Cx 26). Thirty-eight subjects at a median age of 42 years, range 18-60 years with symmetric U-shaped audiograms classified as sensorineural were included in the genetic investigation. The gender distribution was 13 males and 25 females. No subjects had any indication of syndromic HI, and any possible exogenous factor that might cause HI was excluded. Three subjects had self-reported prelingual HI and 34 subjects had self-reported postlingual HI. Thirty-five subjects had one or more family members with HI. In 19 subjects the entire Cx 26 gene was examined, whereas 19 subjects were investigated for the 35delG mutation only. One female with mild HI and postlingual onset of the HI was heterogeneous for the L9OP-mutation in the Cx 26 gene. In all other subjects no mutations in the Cx 26 gene could be identified. Mutations of the Cx 26 gene are very rare among subjects exhibiting a U-shaped phenotype of the audiogram. However the majority of the investigated subjects (35/38) had a family history of HI and it seems therefore reasonable to ascribe U-shaped hearing deficit to genetic factors which has to be searched for in alternative gene mutations.

The Role of a Family History in King Kopetzky Syndrome (Obscure Auditory Dysfunction)

King Kopetzky Syndrome (KKS) is a common condition in which individuals with normal audiograms complain of hearing difficulties, particularly in noisy places. Several studies have shown many patients with KKS to have a family history of hearing problems. In 82 consecutive patients with KKS and normal middle ear function, we compared the performance of those with and without a family history of hearing impairment on a number of sensitized tests. Those with a family history were more likely to have notches on Audioscan testing (p<0.005) and these notches were broader than those found in patients with no family history (p<0.05). There was also a tendency for those with a family history to be more likely to have notches on DPOAEs (p<0.07), and the reproducibility of the TOAEs was poorer in those with a family history. Psychological testing showed males with a family history to have higher scores on free-floating anxiety (p<0.01) and obsessionality (p<0.05).

Investigation of hearing impairment in Cavalier King Charles spaniels using auditory brainstem response audiometry.

Auditory brainstem response audiometry was used to investigate nine Cavalier King Charles spaniels with a history of hearing impairment. Successful recordings were made in all cases. In eight of the dogs, the hearing impairment was between 40 and 85 decibels re normal hearing level. In addition to confirming the degree of impairment in each ear, information was obtained concerning the site of the lesion. The auditory brainstem technique may have an important role to play in assessing treatment outcome. Other applications include screening animals used in breeding programmes as well as working dogs requiring good binaural hearing.

Adult auditory learning and training.

We describe a theoretical framework that distinguishes stimulus, procedural, and task aspects of learning, and we suggest that this framework may allow an improved understanding of acclimatization and late-onset auditory deprivation. We review the literature on learning after sensorineural hearing loss and after the provision of amplification. We then examine the possibility of using training to improve the speech-understanding skills of listeners with sensorineural hearing loss after provision of amplification. Here, we concentrate on techniques recently demonstrated to encourage the acquisition of non-native phonetic contrasts in second-language learners. We argue that there are three general principles associated with auditory learning and training: 1) the more complex the task, the longer the learning period required; 2) the greater the similarity between training and test tasks, the greater the transfer of training; and 3a) the more familiar the stimulus materials, the faster the subsequent learning. When training for speech identification in everyday life, maximizing the opportunity for the listener to cope with the acoustic variability found in natural speech, both within and between talkers, is important. We, therefore, argue that the third principle should be extended: 3b) the more the training set exemplifies the acoustic variability found within and between talkers, the greater the transfer to open-set speech identification in everyday life. Throughout the review, we show that individual differences in learning are observed in the rate of acquisition and in the level of asymptotic performance. We argue that it is possible to postulate modulators of learning that may account for some of these individual differences. Possible candidates for influential modulators are: 1) the history of hearing impairment--the longer the history, the longer the time taken to improve performance and, possibly, the lower the asymptotic level of performance; 2) the severity and pattern of hearing loss; 3) the degree of asymmetry in the hearing loss and its effect on the binaural organization of the hearing system; and 4) the level of patient adaptability and cognitive abilities, such as attentional control and short-term memory span.