Search PubMed⌕ Search

Biomedical subjects

I R Swan

Publications and source records attributed to I R Swan.

34 records · Page 2Linked to original sources
PubMed1989

Clinical role of informal tests of hearing.

Clinical tests of hearing are regularly used in adults but their role, now that pure-tone audiometry is almost universally available, has not been evaluated by modern methods of analysis including sensitivity and specificity. Free-field voice testing was carried out in 101 patients and the Rinne tuning-fork test in a different group of 127 patients prior to clinical or audiometric evaluation. The results were subsequently compared to air and bone conduction pure-tone thresholds assessed using rigorous standards. Depending on the audiometric definition as to what constitutes a hearing impairment, the sensitivity of free-field voice testing to identify such an impairment because of an inability to hear a whispered voice at two feet (60 cm.) was 86 per cent or better with the specificity being in the region of 90 per cent. In the Rinne test the 256 Hz fork was superior to the 512 Hz fork (p less than 0.05) and the loudness comparison method superior to the threshold decay method (p less than 0.01) in detecting an air-bone gap. Combining the responses to the two forks did not improve the results. The Rinne test with the 256 Hz fork will identify correctly 48 per cent of individuals with a 15 dB, 69 per cent with a 20 dB, 87 per cent with a 25 dB, and 95 per cent with a 30 dB conductive impairment. In all instances the specificity is greater than 90 per cent.

Audiometry, Pure-Tone↗
PubMed1989

Diagnostic vetting of individuals with asymmetric sensorineural hearing impairments.

Audiological and vestibular tests were administered conjointly in a neurological or general ORL clinic to exclude cerebellopontine angle (CPA) tumours. This study aimed to assess the efficiency of various tests in achieving that exclusion with the minimum of unnecessary investigations. All patients received the full battery of auditory brainstem responses, acoustic reflex thresholds and decay, alternate binaural loudness balance and ENG and caloric testing. All patients who did not have normal auditory brainstem responses proceeded to high resolution CT scanning. One hundred and fifteen patients were investigated and four acoustic neuromas were diagnosed. The efficiency of these tests in a general ORL clinic is very much poorer than often suggested, due largely to the number of occasions on which the tests cannot be done, and to the very small proportion of the test population who have CPA tumours.

Adolescent↗
PubMed1989

Clinical masking with tragal rubbing and the Bárány noise-box.

When assessing hearing by free-field voice testing, it is essential to mask the non-test ear. An appropriate method of masking must be chosen to suit the stimulus used. This study demonstrates that tragal rubbing is an effective means of masking a whispered or conversational voice, but a Bárány noise-box is required to mask a loud voice. However, a Bárány noise-box should not be used routinely as it is likely to overmask a normal or mildly impaired ear.

Adult↗
PubMed1989

The Bing test in the detection of conductive hearing impairment.

The Bing test is based on the principle that occlusion of the external auditory meatus improves the perception of bone-conducted sounds unless there is a conductive hearing impairment. However, its sensitivity and specificity have not been reported. Tuning-fork and audiometric Bing tests were carried out on 126 patients with otological symptoms prior to any otological history or examination. Test results were compared with the pure tone air-bone gaps. The specificity and sensitivity of each test method was estimated. The tuning-fork Bing test was less sensitive than the audiometric Bing test, but had greater specificity. However, the Rinne test with the 256 Hz fork and the loudness comparison method was more sensitive than the Bing tuning-fork test, and had similar specificity. The Rinne is therefore the better test for clinical use.

Adult↗
PubMed1988

The management of otitis media with effusion in adults.

The management of 38 patients with idiopathic adult onset otitis media with effusion was evaluated retrospectively. Data from 50 ears were reviewed. The standard treatment consisted of myringotomy and grommet insertion. The patients were followed up for an average period of 27 months. Only 2 ears maintained a significant improvement in the air-bone gap when reviewed approximately 3 months following grommet extrusion. In all of the others, the hearing impairment recurred, and continued to recur despite multiple grommet insertions in several patients. It is concluded that adult onset otitis media with effusion has a low tendency to resolve, and that conventional surgical measures have little to offer in its management.

Adult↗
PubMed1987

Optimum side for fitting a monaural hearing aid. 3. Preference and benefit.

Benefit from a simulated monaural hearing aid was assessed in diotic and dichotic listening conditions in 92 subjects with bilateral, mild to moderate sensorineural hearing impairment. In diotic conditions, subjects scored better on a speech identification task with an 'aid' in their better hearing ear. However, in dichotic conditions, a 'hearing aid' the better hearing ear was of no benefit when the signal came from the side of the poorer ear, while a 'hearing aid' in the poorer ear was of benefit in all listening situations. These results support the hypothesis that patients' preference for using an aid in their poorer hearing ear (Swan et al., 1987) is based on the desire to minimise their disability in the most disadvantageous listening situations.

Aged↗
PubMed1987

Optimum side for fitting a monaural hearing aid. 1. Patients' preference.

The criteria generally used to decide in which ear to fit a monaural hearing aid are based on theory or anecdote and have not been verified by experimental observation. In this study to determine optimum side of fitting, 58 new hearing aid users were fitted with a hearing aid in one ear for 10 weeks, and then fitted in the other ear for a further 10 weeks. Subsequently, the subjects were asked their preference for side of hearing aid use and their reasons for this preference. 30 (52%) subjects reported better hearing with their aid in one ear than in the other; 24 (80%) of these preferred the ear with the poorer half-peak level elevation on a speech audiogram. The remaining 28 (48%) reported no difference in their aided hearing ability between ears, though 20 preferred one ear for practical reasons, unrelated to audiometric parameters. A patient's preference for side of fitting can be predicted from audiometric data but with only modest reliability. It is, therefore, recommended that bilateral ear moulds should be routinely provided for bilateral mild to moderate hearing impairment (speech frequency average less than 75 dB HL). If it is decided that only one ear mould should be provided, this should be made for the poorer hearing ear. The poorer hearing ear is best identified from the half-peak level elevation on a speech audiogram.

Adult↗
PubMed1987

Optimum side for fitting a monaural hearing aid. 2. Measured benefit.

The benefit obtained from wearing a hearing aid in either ear was assessed in 52 subjects using an audiovisual test. The sound source was located directly in front of the subject. Overall the subjects obtained more benefit with their aid in their better hearing ear, despite having expressed a preference for using the aid in their poorer hearing ear. Seven of the subjects who had asymmetrical hearing were tested further using an auditory test with the sound source either in front of the subject or to either side. The results suggest that the subjects' preference for the poorer hearing ear are based on a desire to minimise their disability in the most disadvantageous listening situations.

Functional Laterality↗
PubMed1986

A cross-over study of side of hearing aid provision.

No previous study has investigated which ear should be fitted with a hearing aid. Fifty-eight patients with bilateral hearing loss of 25-75 dB HL were sequentially fitted with an ear level hearing aid for 10 weeks in each ear. Patients were then asked their preference for side of fitting, and their reasons for this preference. Thirty-five patients had symmetrical hearing: 17 (49%) preferred one ear because they could hear better with the aid in that ear, and 12 (34%) chose one side for practical reasons. Twenty-three patients had asymmetrical hearing: 8 (35%) preferred one side for practical reasons, and 13 (57%) could hear better with the aid in one ear, which was invariably the poorer hearing ear. As the preferred ear cannot be reliably predicted, bilateral ear moulds should be provided. If only one mould is provided, it should be for the poorer hearing ear.

Adult↗
PubMed1986

A scale for hearing aid benefit measures and auditory disability.

Quoting disability scores or measures of hearing aid benefit based on percent correct word identification or on dB signal-to-noise ratio at criterion performance poses a communication problem as scientists and clinicians may have no intuitive understanding of the scales involved. In particular, percent correct does not allow direct comparison of differences obtained at different performance levels, for example by different subject groups. In circumstances where the better ear hearing levels are known to be a major determinant of disability, it is both possible and legitimate to transform performance measures such as percent correct into a dB HL equivalent. In two sets of data from clinical research projects this relationship is shown to be linear, allowing a particularly simple transformation and giving an already understood scale. This transformation procedure has been cross-validated against the acoustic gain used in a sample of patients with conductive losses where the hearing loss is purely an attenuation. The procedure is offered as a metric for expressing the benefits of management.

Correction of Hearing Impairment↗
PubMed1985

The doubtful value of tympanometry in the diagnosis of otosclerosis.

Many consider that the compliance of the middle ear as measured from the tympanogram can be helpful in diagnosing otosclerosis. To test this assertion, the compliance in 34 individuals with surgically proven otosclerosis was compared with the compliance in 34 age and sex matched, normal controls, randomly selected from the population. Though the mean compliance was different in the two groups, there was considerable overlap in the range of values which severely limits the practical usefulness of tympanometry. If the level of compliance is taken at which a false negative diagnosis would be made in 10 per cent of otosclerotic ears, a false positive diagnosis of otosclerosis would be made in 88 per cent of normal ears. If the level of compliance is taken at which a false positive diagnosis of otosclerosis would be made in 10 per cent of normal ears, 72 per cent of ears with otosclerosis would be considered normal. It is concluded that tympanometry will not help to arrive at a diagnosis of otosclerosis.

Acoustic Impedance Tests↗
PubMed1984

Phasor admittance measurements of the middle ear. II. Normal phasor tympanograms and acoustic reflexes.

Phasor admittance trajectories obtained during tympanometry and acoustic reflex measurements at 220 and 660 Hz were obtained from 67 normal ears. The distributions of natural frequency and resistance derived from these phasor trajectories provide normative data for the technique. Median values of 817 and 714 Hz for natural frequency were obtained respectively for tympanometry and acoustic reflexes. Median resistances were 139 and 555 ohms. The distributions of these parameters from tympanometry and acoustic reflexes were significantly different for both resistance and natural frequency, supporting the assumption that the two procedures measure different aspects of middle-ear vibration, which we have attributed to ossicular chain vibration and to uncoupled vibration of the tympanic membrane. Correlation data are also consistent with this assumption.

Acoustic Impedance Tests↗
PubMed1982

Hearing loss in minor head injury.

A prospective otological and audiological study was made of 130 consecutive persons with head injuries. A comparison was made with 87 consecutive persons with traumatic injuries but without head injuries. Five (4%) of the persons with head injuries had an unsuspected temporal bone fracture evident on otoscopy but not on routine skull roentgenography. These persons had a significant sensorineural hearing loss at 4 and 8 kHz compared with other patients with head injuries. Routine otoscopic examination is considered advisable in all persons with head injuries. No significant difference in the hearing was detected in persons with head injuries without a temporal bone fracture compared with control subjects.

Adolescent↗
PubMedDate not supplied

Auditory rehabilitation: needs and realities on long-stay wards for elderly people.

A survey was made of the problem of age-related hearing impairment within a sample of National Health Service long-stay wards for elderly people. Detailed assessment of hearing was completed for 188 residents derived from 15 long-stay wards, located within nine Scottish hospitals. The sample residents were more than four times as likely to need a hearing aid as their contemporaries in the general population. Of the 131 people considered to be potential hearing aid candidates, 103 (78%) demonstrated a positive attitude towards hearing aids ownership. Medical policies on the study wards were not considered sensitive to the needs of the hearing-impaired; screening was haphazard and specialist referral problematic.

Aged↗