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Biomedical subjects

J M Gulliver

Publications and source records attributed to J M Gulliver.

4 recordsLinked to original sources

Auditory temporal resolution in multiple sclerosis.

Disturbances of hearing in multiple sclerosis patients have been variably reported, likely because standard audiologic testing emphasizes assessment of peripheral, rather than central, auditory function. This study investigated a group of patients with multiple sclerosis (MS), prospectively selected on the basis of magnetic resonance imaging (MRI) scans. Five of these patients had demyelinating lesions that included the rostral auditory fibre tracts, while another seven patients had lesions restricted to brainstem auditory sites. A further four had no lesions in the distribution of their auditory pathways. A comprehensive battery of audiometric tests, including standard audiometry and retrocochlear testing, was performed. In addition, their findings on electrophysiologic testing, including auditory brainstem responses (ABR) and middle latency responses (MLR), were studied. Finally, their performances in gap detection and speech recognition in continuous and interrupted background noise were examined to assess their auditory temporal resolution. The MS patients were found to be selectively impaired under the interrupted masker of this speech-in-noise paradigm, confirming a temporal processing defect. Furthermore, these patients' performances suggested a predominant role of forebrain pathways in mediating auditory temporal resolution.

Adult

Impaired word recognition in noise by patients with noise-induced cochlear hearing loss: contribution of temporal resolution defect.

Fifteen patients with mild noise-induced cochlear hearing loss reported a selective difficulty in understanding speech in noisy settings. To examine the hypothesis that a temporal resolution defect was responsible for this difficulty, the patients were tested for their recognition of monosyllabic words presented against continuous and interrupted wide-band noise backgrounds, at each of seven signal-to-noise ratios. Their recognition performance was compared with that of normal listeners studied with the same paradigms. By comparison with the controls, the group with cochlear hearing loss showed a significant recognition impairment only for words presented against the interrupted masker. This finding was in keeping with the existence of a temporal resolution defect in cochlear disease, though it need not indicate a stimulus timing defect at the level of individual cochlear neurons.

Adult

Disturbed speech intelligibility in noise despite a normal audiogram: a defect in temporal resolution?

Patients with complaints of disturbed speech intelligibility in noise, despite normal standard audiograms, constitute a unique yet not uncommon population of listeners. The literature on this patient group is reviewed, and the term Idiopathic Discriminatory Dysfunction (IDD) is introduced in an attempt to standardize and qualify the distinct characteristics of this entity. Preliminary studies of these patients have hypothesized both frequency and temporal resolution deficits underlying this impairment. A representative group of 15 patients suffering from IDD were tested using a new speech-in-noise paradigm designed to test temporal resolution. These patients were found to have near-normal temporal resolving capacity as determined by this task.

Adult

A fatal copper sulfate poisoning.

An 11-year-old female died within hours of accidentally ingesting a solution of copper sulfate. A postmortem blood sample was found to contain 66 micrograms/mL copper. The initial qualitative identification of this poison in the body organs and fluids was by means of SEM-microprobe analysis (SEM-MPA) and X-ray fluorescence (XRF). The samples were quantified by atomic absorption spectrometry.

Child