Neuromodulation : journal of the International Neuromodulation Society
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The objective of this study is to determine the usefulness of single-patient, randomised, controlled trials (N-of-1 trials) in assessing the efficacy of deep brain stimulation (DBS) in neuropathic pain. Seven patients with various causes of intractable neuropathic pain underwent insertion of deep brain stimulating electrodes into the periventricular gray area or ventroposterolateral nucleus of the thalamus. Preoperatively, pain was measured using Visual Analog Scales (VAS) and the McGill Pain Questionnaire (MPQ). ⋯ The results of the N-of-1 trials were most similar to the MPQ scores and showed that three of seven patients could accurately predict whether the DBS was on or off. In the N-of-1 trials, the time between changing the DBS from on to off (or vice versa) had an effect on the results and probably underestimated the efficacy. We conclude that N-of-1 trials are a useful tool for assessing DBS efficacy.
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The aim of the present study was to investigate the modulation and functional importance of nociceptive withdrawal reflexes elicited from the sole of the foot and recorded from the soleus (SOL) and tibialis anterior (TA) muscles during gait. Cutaneous electrical stimulation delivered at four locations of the sole of the foot was used to elicit the withdrawal reflex. Reflexes were recorded from eight healthy subjects during treadmill walking. ⋯ The TA reflex, expressed as a proportion of the electromyogram during unperturbed gait, was smallest during swing (p < 0.05, compared with stance) whereas the SOL reflex was maximal during swing (p < 0.05, compared with stance). The results suggest that the modulation of the reflex promotes an appropriate withdrawal while preserving balance and continuity of motion. These results may have applications in assisting gait of hemiplegics.
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The Prospective Italian Register of spinal cord stimulation (SCS) was designed to evaluate the clinical outcome of patients with severe peripheral arterial occlusive disease (PAOD) treated with SCS. Baseline data were collected for all patients with PAOD undergoing SCS treatment (September 1998 to February 2001) at 34 participating centers. If, after a 2- to 3-week trial, SCS demonstrated significant clinical benefits, a permanent implantable pulse generator was implanted. ⋯ All PAOD parameters improved significantly during follow-up. At 12 months postimplantation, 76.1% of patients were responsive to SCS therapy. The reduction in the use of analgesics and the number and duration of hospital stays offers clear economic advantages.
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Deep Brain Stimulation is an effective treatment of generalized dystonia. Optimal stimulation parameters vary between patients. This article investigates the influence of electrical brain impedance and delivered current on the brain response to stimulation. ⋯ The absolute impedance did not significantly correlate with the final outcome. We conclude that the reversible decrease of impedance reflects an adaptive long-term mechanism, which could be due to a plasticity phenomenon, but has no prognostic value. Impedance and current measurements give new complementary information for parameter adjustment and trouble shooting and should therefore be included in all patients' follow-up.