Biomedical subjects

Rosalyn A Davies

Publications and source records attributed to Rosalyn A Davies.

3 recordsLinked to original sources

PubMed2004

Deficient auditory interhemispheric transfer in patients with PAX6 mutations.

PAX6 mutations are associated with absence/hypoplasia of the anterior commissure and reduction in the callosal area in humans. Both of these structures contain auditory interhemispheric fibers. The aim of this study was to characterize central auditory function in patients with a PAX6 mutation. We conducted central auditory tests (dichotic speech, pattern, and gaps in noise tests) on eight subjects with a PAX6 mutation and eight age- and sex-matched controls. Brain magnetic resonance imaging showed absent/hypoplastic anterior commissure in six and a hypoplastic corpus callosum in three PAX6 subjects. The control group gave normal central auditory tests results. All the PAX6 subjects gave abnormal results in at least two tests that require interhemispheric transfer, and all but one gave normal results in a test not requiring interhemispheric transfer. The left ear scores in the dichotic speech tests was significantly lower in the PAX6 than in the control group. These results are consistent with deficient auditory interhemispheric transfer in patients with a PAX6 mutation, which may be attributable to structural and/or functional abnormalities of the anterior commisure and corpus callosum, although the exact contribution of these two formations to our findings remains unclear. Our unique findings broaden the possible functions of PAX6 to include neurodevelopmental roles in higher order auditory processing.

Adult↗

PubMed2004

Simulator based rehabilitation in refractory dizziness.

UNLABELLED: Patients with chronic vestibular symptoms are common in neurological practice but the most effective treatment remains an open question. The purpose of our study was to conduct a controlled, between-group comparison of patients' responses to a customised exercise regime (Group C, for customised) versus treatment additionally incorporating simulator based desensitisation exposure (Group S, for simulator) integrating whole-body or visual environment rotators. Forty chronic peripheral vestibular patients who had previously undergone conventional vestibular rehabilitation without notable improvement were randomly assigned into Group C or S. Individuals attended therapy sessions twice weekly for eight weeks and were provided with a customised home programme. Response to treatment was assessed at four-week intervals with dynamic posturography, vestibular time constants, and questionnaires concerning symptoms, symptom-triggers and emotional status. At final assessment posturography and subjective scores had significantly improved for both groups, although Group S showed greater improvement. A statistically significant improvement for visual vertigo symptom scores was noted only for Group S (p < 0.01; total improvement 53.5 %). Anxiety and depression levels significantly decreased for both groups; improvements were significantly correlated particularly to improvements in visual vertigo (SCQ) (p < 0.01; r = 0.53 and r = 0.57, respectively). Significant differences were noted between groups (p = 0.02) for posturography scores. Vestibular time constants showed no notable change in either group. CONCLUSIONS: Both groups improved but exposure to simulator motion gave overall better results. These effects were also observed in psychological symptoms and partly relate to simulator effects on visual vertigo symptoms. Visual motion and visuo-vestibular conflict situations should be incorporated in the rehabilitation of patients with refractory dizziness.

Adult↗

PubMed2002

Effectiveness of the particle repositioning maneuver in benign paroxysmal positional vertigo with and without additional vestibular pathology.

OBJECTIVE: We compared the treatment outcome of patients with benign paroxysmal positional vertigo unassociated with additional objective evidence of vestibular pathology (BPPV) with that in patients who did demonstrate additional vestibular pathology on standard neurotologic testing (BPPV+). STUDY DESIGN: An open, retrospective, record-based study. SETTING: Specialized outpatient dizziness clinic. PATIENTS AND METHODS: We reviewed 58 unselected patients with a Dix-Hallpike test demonstrating positioning nystagmus characteristic of BPPV, who were treated during the past 4 years with the particle repositioning maneuver. Before treatment, all patients underwent detailed clinical and laboratory neurotological testing. MAIN OUTCOME MEASURES: The treatment outcome was assessed with regard to persistence of symptoms and the presence of positioning nystagmus on Dix-Hallpike testing. RESULTS: Seventy-eight percent of patients with BPPV no longer demonstrated characteristic positional nystagmus after 1 particle repositioning maneuver compared with 71% of patients with BPPV+ (p = 0.56) who did, whereas 13% of the BPPV and 14% of the BPPV+ group required more than 1 treatment to be rendered nystagmus negative on Dix-Hallpike testing (p = 0.89). However, 14% of patients with BPPV remained dizzy, compared with 63% patients from the BPPV+ group, despite a negative Dix-Hallpike test after treatment (p = 0.0018). Patients with horizontal canal paresis (n = 15) had a better outcome than patients with central vestibular dysfunction (n = 7, p = 0.006). Etiologic factors seemed to affect outcome-patients with idiopathic BPPV and those with a preceding acute vestibular neuronitis had a tendency for a better outcome than BPPV patients with any other etiology (p = 0.058). CONCLUSION: Our study demonstrates that patients with BPPV+ do not have a worse prognosis with respect to resolution of positional nystagmus, on performing the particle repositioning procedure, compared with patients with uncomplicated BPPV. However, they do suffer incomplete resolution of symptoms because of a coincidental anterior or horizontal canal dysfunction and otolithic or central vestibular dysfunction. It appears that the majority of patients with BPPV+ need further vestibular rehabilitation after the particle repositioning maneuver.

Acute Disease↗