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Biomedical subjects

P Silburn

Publications and source records attributed to P Silburn.

8 recordsLinked to original sources
PubMed2005

Quantitative assessment of driving performance in Parkinson's disease.

OBJECTIVES: The primary aim of this study was to determine how Parkinson's disease (PD) affects driving performance. It also examined whether changes in driver safety were related to specific clinical disease markers or an individual's self rating of driving ability. METHODS: The driving performance of 25 patients with idiopathic PD and 21 age matched controls was assessed on a standardised open road route by an occupational therapist and driving instructor, to provide overall safety ratings and specific driving error scores. RESULTS: The drivers with PD were rated as significantly less safe (p<0.05) than controls, and more than half of the drivers with PD would not have passed a state based driving test. The driver safety ratings were more strongly related to disease duration (r = -0.60) than to their on time Unified Parkinson's Disease Rating Scale (r = -0.24). Drivers with PD made significantly more errors than the control group during manoeuvres that involved changing lanes and lane keeping, monitoring their blind spot, reversing, car parking, and traffic light controlled intersections. The driving instructor also had to intervene to avoid an incident significantly more often for drivers with PD than for controls. Interestingly, driver safety ratings were unrelated to an individual's rating of their own driving performance, and this was the case for all participants. CONCLUSIONS: As a group, drivers with PD are less safe to drive than age matched controls. Standard clinical markers cannot reliably predict driver safety. Further studies are required to ascertain whether the identified driving difficulties can be ameliorated.

Aged↗
PubMed2003

Defining a role for the subthalamic nucleus within operative theoretical models of subcortical participation in language.

OBJECTIVE: To investigate the effects of bilateral, surgically induced functional inhibition of the subthalamic nucleus (STN) on general language, high level linguistic abilities, and semantic processing skills in a group of patients with Parkinson's disease. METHODS: Comprehensive linguistic profiles were obtained up to one month before and three months after bilateral implantation of electrodes in the STN during active deep brain stimulation (DBS) in five subjects with Parkinson's disease (mean age, 63.2 years). Equivalent linguistic profiles were generated over a three month period for a non-surgical control cohort of 16 subjects with Parkinson's disease (NSPD) (mean age, 64.4 years). Education and disease duration were similar in the two groups. Initial assessment and three month follow up performance profiles were compared within subjects by paired t tests. Reliability change indices (RCI), representing clinically significant alterations in performance over time, were calculated for each of the assessment scores achieved by the five STN-DBS cases and the 16 NSPD controls, relative to performance variability within a group of 16 non-neurologically impaired adults (mean age, 61.9 years). Proportions of reliable change were then compared between the STN-DBS and NSPD groups. RESULTS: Paired comparisons within the STN-DBS group showed prolonged postoperative semantic processing reaction times for a range of word types coded for meanings and meaning relatedness. Case by case analyses of reliable change across language assessments and groups revealed differences in proportions of change over time within the STN-DBS and NSPD groups in the domains of high level linguistics and semantic processing. Specifically, when compared with the NSPD group, the STN-DBS group showed a proportionally significant (p<0.05) reliable improvement in postoperative scores achieved on the word test-revised (TWT-R), as well as a reliable decline (p<0.01) in the accuracy of lexical decisions about words with many meanings and a high degree of relatedness between meanings. CONCLUSIONS: Bilateral STN-DBS affects certain aspects of linguistic functioning, supporting a potential role for the STN in the mediation of language processes.

Aged↗
PubMed1998

Neuropsychological, neurological and functional outcome following pallidotomy for Parkinson's disease. A consecutive series of eight simultaneous bilateral and twelve unilateral procedures.

Intellectual, psychological and functional outcomes were evaluated in a consecutive series of 20 Parkinsonian patients who had unilateral (UPVP) or simultaneous bilateral posteroventral pallidotomy (BPVP) using Image Fusion and Stereoplan (Radionics Inc., Boston, Mass., USA) with stimulation for lesion localization. Comprehensive baseline and 3-month postoperative neuropsychological and neurological assessment protocols were administered together with questionnaire measures of functional disability, quality of life and psychological symptomatology. Changes in patients' clinical presentation and scores on psychometric tests, questionnaires and observational rating scales were then examined. We observed no new neuropsychiatric sequelae directly related to pallidotomy. Cognitive sequelae were restricted to selective reductions in categorical verbal fluency following UPVP (P < 0.001) and BPVP (P < 0.01) and a reduction in phonemic verbal fluency following BPVP (P < 0.01); these changes were not reported subjectively. A fall in diadochokinetic rates (P < 0.01) and some subjective reports of a worsening in pre-existing dysarthria, hypophonia and hypersalivation/drooling following BPVP also suggested changes in speech motor apparatus; however, these changes did not have significant functional consequences. There was one case of more generalized cognitive impairment following BPVP. We also observed significant symptomatic improvement on neurological rating scales; following UPVP, Total Unified Parkinson's Disease Rating Scale (UPDRS) scores improved by 27% (P < 0.01) and following BPVP the improvement was 53% (P < 0.05). Patients' perceptions of reduced postoperative functional disability and improvements in 'quality of life' also achieved statistical significance on a number of both physical and psychosocial questionnaire subscales.

Activities of Daily Living↗
PubMed1997

A study of motor performance and motor learning in episodic ataxia.

Episodic ataxias are rare disorders in which periodic episodes of ataxia are separated by normal or near normal motor behaviour. They probably arise from dysfunctional membrane ion channels in the cerebellum. A patient with episodic ataxia EA-2 performed three motor tasks, before, during and after an ataxic episode. In all three tasks there were significant performance deficits during the ataxic episode. Two of the tasks also assessed motor adaptation (prism adaptation) or motor learning (ideogram drawing). In neither task was there significant disruption of motor adaptation or learning. These results suggest that the cerebellum may have separate roles in learning and in performance of visually guided movements, and that the dysfunction in this patient affected only his motor performance.

Ataxia↗
PubMed1996

Fatal familial insomnia: a seventh family.

A 60-year-old woman with a typical history of fatal familial insomnia (FFI) had FFI proven by histologic examination and molecular testing. Her son, who died at the age of 20 in 1978, had a rapidly progressive dementing illness without reported insomnia. He carried the characteristic mutation for FFI and is the youngest patient reported with this condition.

Adult↗
PubMed1995

Familial periodic cerebellar ataxia without myokymia maps to a 19-cM region on 19p13.

Familial periodic cerebellar ataxia (FPCA) is a heterogeneous group of rare autosomal dominant disorders characterized by episodic cerebellar disturbance. A potassium-channel gene (KCNA1) has been found to be responsible for one of its subgroups, familial periodic cerebellar ataxia with myokymia (FPCA/+M; MIM 160120). A different subgroup that is not associated with myokymia (FPCA/-M; MIM 108500) was recently mapped to chromosome 19p. Here we have performed linkage analysis in two large families with FPCA/-M that also demonstrated neurodegenerative pathology of the cerebellum. Three markers in 19p13 gave significant lod scores (> 3.0), while linkage to KCNA1 and three known loci for spinocerebellar ataxia (SCA1, SCA2, and SCA3) was excluded. The highest lod score was obtained with the marker D19S413 (4.4 at recombination fraction 0), and identification of meiotic recombinants in affected individuals placed the locus between the flanking markers D19S406 and D19S226, narrowing the interval to 19 cM. A CAG trinucleotide-repeat expansion was detected in one family but did not cosegregate with the disease.

Cerebellar Ataxia↗