Biomedical subjects

R M Barr-Hamilton

Publications and source records attributed to R M Barr-Hamilton.

5 recordsLinked to original sources

PubMed1992

The evaluation of dizziness in elderly patients.

Twenty-one elderly patients with dizziness underwent a comprehensive medical and otoneurological evaluation. The majority had vertigo, limited mobility and restricted neck movements. Poor visual acuity, postural hypotension and presbyacusis were also frequent findings. Electronystagmography revealed positional nystagmus in 12, disordered smooth pursuit in 18, and abnormal caloric responses in nine. Magnetic resonance imaging showed ischaemic changes in six out of eight patients. Although dizziness in the elderly is clearly multifactorial, the suggested importance of vertebrobasilar ischaemia warrants further consideration as vertigo has been shown to be a risk factor for stroke.

Aged↗

PubMed1991

Ototoxicity of cis-platinum and its relationship to eye colour.

The following hypothesis is presented: that the susceptibility of an individual patient to hearing loss as a result of cis-platinum administration can be predicted on the basis of eye colour. The rationale is that the melanin content of the inner ears is related to that of the eyes; dark eyes contain more melanin than light-coloured eyes; and melanin causes the accumulation of the ototoxic drug within the inner ear. Hence those with dark eyes will suffer greater damage to the hearing than those with pale eyes. An investigation that confirmed this hypothesis is reported. In addition to cochlear damage there is a significant likelihood of damage to the auditory nerve as a result of the treatment.

Adult↗

PubMed1990

Ear wax removal: a survey of current practice.

OBJECTIVE: To determine the methods of removing ear wax used by local general practitioners and the incidence of associated complications. DESIGN: Postal survey of 312 general practitioners serving a population of about 650,000; supplementary study of ear, nose, and throat outpatients to quantify the improvement in aural acuity after wax removal. SETTING: Catchment area of the Edinburgh otolaryngological unit. PARTICIPANTS: 289 General practitioners who responded to the survey; 21 outpatients in the ear, nose, and throat department with occlusive wax. RESULTS: 274 General practitioners removed wax by syringing, but only 53 (19%) always performed the procedure themselves; the remainder routinely delegated the task to practice nurses, some of whom had received no instruction. Ears were rarely examined again after the procedure. Complications had been experienced by 105 practitioners (38%) and included perforation, canal lacerations, and failure of wax removal. The removal of occlusive wax improved hearing by a mean of 5 dB over the frequencies analysed. CONCLUSIONS: About 44,000 ears are syringed each year in the area and complications requiring specialist referral are estimated to occur in 1/1000 ears syringed. The incidence of complications could be reduced by a greater awareness of the potential hazards, increased instruction of personnel, and more careful selection of patients.

Cerumen↗

PubMed1978

A theoretical approach to the loop induction system.

In a study of the properties of hearing aids with loop induction coils, it was observed that a group of high-powered aids used primarily for their extended low frequency responses had poor low frequency responses when used on loop input. The consequences of these characteristics are discussed. To asisst in the problem of loop design, equations are presented expressing the magnetic field strength at any point in terms of the electric current and loop location. These were found to predict the field strength with good accuracy, and may be used to calculate the field strength and its variation, produced by almost any loop configuration.

Acoustics↗

PubMedDate not supplied

Relief of the occluded ear sensation to improve earmold comfort.

Earmold comfort is an important factor in the overall satisfaction a hearing-impaired person has with a hearing aid system. Recent research into the subjective effects of earmold venting indicates that, for the naive hearing-aid user, the solid mold produces a "closed" and "blocked" sensation that is relieved to a degree, depending on the vent diameter. To improve earmold comfort, all earmolds should be vented. However, there are certain types of hearing loss where conventional venting techniques would be undesirable, in particular, cases of severe to profound hearing loss where venting would not only adversely affect the desired frequency response characteristics of the hearing aid but would also lead to serious acoustic feedback problems. For this reason a simple system has been developed with sintered filters in the vent line, thus allowing all earmolds to be vented to relieve the occluded ear sensation although retaining the acoustic characteristics of the closed earmold.

Adult↗