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Biomedical subjects

R P Gannon

Publications and source records attributed to R P Gannon.

At least 19 recordsLinked to original sources
PubMed1984

Factors affecting the prevalence of tinnitus.

The prevalence of tinnitus was studied in a large population of noise-exposed workers. It was found that 6.6% had tinnitus which was more than momentary. Results of two other studies were compared. Factors possibly relating to the prevalence of tinnitus were studied. The single most important factor found to be related to tinnitus is hearing level. The higher the hearing level, the faster the rate of increase in the prevalence of tinnitus. Other factors such as sex, age, laterality, smoking and shooting do not seem to have a significant, direct relationship with tinnitus, but they are related to the prevalence of tinnitus indirectly through the influence they have on hearing loss.

Adolescent↗
PubMed1983

The performance of circumaural hearing protectors by dosimetry.

The performance of earmuffs in the actual working environment was studied with two modified dosimeters. It was found that personal hearing protection, at least with earmuffs, is a potentially adequate method of protection against noise-induced hearing loss in most industrial working situations. Most of the problems involving the use of hearing protectors in a hearing conservation program can be overcome by education and proper fitting.

Adolescent↗
PubMed1983

The ear effect as a function of age and hearing loss.

Many studies have shown that the right ear statistically is slightly more sensitive than the left ear, particularly in the male adult population. In this study, we examined the lateral difference in hearing sensitivity, termed the ear effect here, in an industrial noise-exposed, nonshooting population, by sex, age, and hearing level. It was found that the male population had a larger ear effect (right ear being more sensitive) than the female population. The magnitude of the ear effect was found to be significantly related to the hearing threshold level. The ear effect was highest when the threshold was between 30- and 40-dB HL. Several possible causes for the ear effect are discussed.

Adult↗
PubMed1983

Lateral differences in susceptibility to noise damage.

Usually equal noise exposure is considered to cause symmetrical hearing loss. In studying 1 461 audiometric records of claims for noise-induced hearing loss, it was found that 69 (4.7%) had a well-defined pattern of hearing loss in which only 2 kHz is asymmetrical by 20 dB or more. Audiograms of this type suggest that the cochlea of the worse ear has been damaged more extensively towards the apex. Of the 69 cases with a 2-kHz asymmetry, 82.6% had worse hearing thresholds in the left ear at 2 kHz. In 50% of the 69 cases, the asymmetry could not be accounted for even after the examination of their medical, occupational and nonoccupational histories. It is believed that the asymmetry at 2 kHz is a manifestation of a lateral difference in susceptibility to noise damage and that the left ear is the more susceptible one in the majority of cases.

Adult↗
PubMed1983

Asymmetrical noise exposure and hearing loss among shingle sawyers.

Shingle sawyers are exposed to noise predominantly from the left side. This study examined the asymmetry in hearing loss among shingle sawyers and its possible relation to the difference in noise exposure to the two ears. The results suggest that the lateral difference in noise exposure in industry, even in the obvious case of a shingle sawyer, is small. The resulting asymmetrical noise-induced hearing loss is also relatively small. Therefore, significant asymmetry in hearing loss in this type of occupation should be viewed with caution. Special tests and medical examination should be undertaken to determine if there are other contributing factors.

Adult↗
PubMed1981

Shooting, sensorineural hearing loss, and workers' compensation.

Pure-tone audiograms of 29,953 workers with histories of shooting and occupational noise exposure were analyzed. The analysis was based on the asymmetry of hearing loss. Results of this study show that shooting is related to asymmetrical hearing loss, suggesting that shooting may cause an additional amount of hearing loss other than that due to occupational noise exposure. Asymmetry was found to increase as the length of shooting history increased and was significant only at 2 kHz and above and most prominent at 4 kHz. Results also indicated that as long as compensable frequencies remain below 3 kHz the shooting effect is not likely to influence compensation for workers with histories of less than ten years of shooting.

Hearing Loss, Noise-Induced↗
PubMed1981

Speech discrimination and effectiveness of hearing aids under listening conditions similar to those of a transit operator.

Some controversy exists regarding regulations that permit hearing impaired drivers to operate passenger carrying vehicles. In other situations it has been shown that the hearing impaired generally have more difficulty than normals discriminating speech in noise. The present study investigates this under listening conditions simulating those of a transit operator, and also looks at the effects of a hearing aid on speech discrimination in the same situation. One normal hearing group and three groups representing varying degrees of symmetrical sensorineural hearing loss were given a sentence type discrimination test in a background of recorded diesel bus noise at different speech-to-noise ratios. The hearing impaired groups performed more poorly than normals and the use of hearing aids did not affect the performance of the hearing impaired groups. Regulations pertaining to licensing of transit operators should take into account hearing above 2,000 Hz. The results of this study, combined with the possibility of noise damage from amplified noise levels, lead us to conclude that hearing aids should not be worn by transit operators on the job.

Analysis of Variance↗
PubMed1980

Hearing loss due to noise trauma.

Three different types of noise-induced hearing loss have been reported in the literature. The two less common types are described here. Three cases of these two types from our clinic are reported. Since these 2 types of noise-induced hearing loss often involve low frequencies it is important to recognize them in compensation cases.

Adult↗
PubMed1979

Interaction of kanamycin and noise exposure.

The amount of hair cell damage in the cochleas of guinea pigs after exposure to different experimental conditions suggests that a 'safe' level of kanamycin has a potentiating effect on damage due to noise. Such an effect lasts more than 20 days after the cessation of the drug administration.

Animals↗
PubMed1979

Is a healthier person less susceptible to noise-induced hearing loss?

Several studies in the literature suggest that poor health is related to hearing loss. One hundred subjects claiming occupational hearing loss were chosen randomly for this study. Information was obtained on employment, noise exposure, medical history, family history, and use of cigarettes, alcohol, and medication. Physical examination audiometric tests, and biological tests were carried out. Computer analysis of the data with chi-square test did not show conclusively that noise-induced hearing loss is related to poor health, indicated by abnormal biological or physical findings, or both. There were, however, some indications that the presence of cardiovascular risk factors may influence hearing loss.

Analysis of Variance↗
PubMed1978

Auditory and vestibular damage in head injuries at work.

A series of 50 unselected patients who reported a head injury to the Workers' Compensation Board of British Columbia were referred to the AudioVestibular Unit of the Vancouver General Hospital for studies of auditory and vestibular function. All patients were interviewed and examined by a neuro-otology team during the course of their investigation. It was found that dizziness was the most common symptom of which they complained (60%), and bleeding from the ear was the least common (4%). Of the 50 patients studied, 32% showed evidence of either auditory and/or vestibular injury. Of the total number studied, 16% had auditory injuries and 26% had vestibular injuries. The most common auditory injury was unilateral partial loss of hearing. Central vestibular dysfunction was the most common vestibular injury. A study of the most effective means of selecting patients from the population with head injuries for referral for audiology and vestibular testing was undertaken. The most effective combination of symptoms for referral is the presence of one or more of the triad: hearing loss, unsteadiness, or loss of consciousness/amnesia.

Accidents, Occupational↗