Getting a grasp on research: does treatment taint testing of parkinsonian patients?
1999; Oxford University Press; Volume: 122; Issue: 8 Linguagem: Inglês
10.1093/brain/122.8.1597
ISSN1460-2156
Autores Tópico(s)Botulinum Toxin and Related Neurological Disorders
ResumoThe study of motor behaviour in patients with Parkinson's disease whilst on medication is widespread. The reasoning behind this is simple: (i) patients typically come to neurology clinics in the medicated state, making on-site testing in this state convenient to many investigators; (ii) testing in the unmedicated state may pose a hardship for patients; (iii) patients in the advanced stages of the disease may be less inclined to participate whilst off medication, skewing the subject pool; and (iv) testing patients in the unmedicated state may raise liability concerns. While all these issues are legitimate, there appears to be a common misconception that while medication may limit the interpretation of negative findings (i.e. lack of differences between patients and controls), positive findings are valid, or even more robust, if observed in the medicated state. We believe that both positive and negative findings from medicated Parkinson's disease patients must be interpreted with caution. While the beneficial effects of l-dopa are extraordinary (at least temporarily), accumulating evidence suggests that l-dopa (and/or other anti-parkinsonian medications) may actually cause some of the motor deficits observed in Parkinson's disease. It is known from clinical observations that over-medication can result in over-striding during locomotion. In Parkinson's disease patients with self-described l-dopa-related worsening of motor performance, tapping and walking times have also been reported to increase following l-dopa administration (Nutt et al. , 1988 …
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