Clinical validation of methods of diagnosis of neuropathy in a field study of United Kingdom sheep dippers.
OBJECTIVE
To investigate the reproducibility of measured indices of chronic peripheral neuropathy from a field study of sheep dippers when compared with similar measurements carried out in a clinical setting.


METHODS
A stratified random sample of field study subjects was invited to attend a clinic. Neuropathy was measured both in the field and at the clinic with a modified version of a standard symptoms questionnaire and quantitative sensory thresholds for hot, cold, and vibration. These were combined into a classification of the likelihood of neuropathy with a neuropathy scoring system. Indicators of sensory abnormality were based on comparison of sensory thresholds to age dependent reference values derived from an external reference group.


RESULTS
Only 51% of subjects were assigned similar classifications in the field and clinic based on the neuropathy scoring system. Of the component indices, grouped symptom scores, with 65% of subjects showing exact agreement, proved to be more reproducible than quantitative sensory test indicators. There were biases in the comparison of field and clinic measurements of hot and vibration sensations, but no evidence of greater variation between individual people in sensory thresholds in the field relative to at the clinic.


CONCLUSIONS
The neuropathy scoring system proved to be of limited reproducibility, due in a large part to the lack of reproducibility of the indicators of sensory test abnormality caused by inadequate temperature control. However, the symptoms score and measured sensory thresholds could be used separately as indices of neuropathy in exposure-response analyses.
Buchanan
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ISD, Scottish Executive, Edinburgh, UK Wellwork Ltd, Edinburgh, UK Department of Neurology, Charing Cross Hospital, London, UK Department of Neurology, INS, Southern General Hospital, Glasgow, UK.
Jamal
G A
GA
Pilkington
A
A
Hansen
S
S
D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000139:chemically induced / Q000175:diagnosis*; D000822:Animal Husbandry; D000818:Animals; D002908:Chronic Disease; D003943:Diagnostic Techniques, Neurological; D005260:Female; D006801:Humans; D007306:Insecticides / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced / Q000175:diagnosis*; D015203:Reproducibility of Results; D012678:Sensation Disorders / Q000175:diagnosis; D012684:Sensory Thresholds; D012720:Severity of Illness Index; D012756:Sheep
D007306:Insecticides; D009943:Organophosphorus Compounds