Somatosensory and Pain Evoked Potentials

This chapter discusses the use of somatosensory evoked potentials (SEPs) and pain evoked potentials for diagnostic purposes. The generators of SEPs following upper limb stimulation have been identified through intracranial recordings, permitting the analysis of somatosensory disorders caused by neurological diseases. Laser activation of fibers involved in thermal and pain sensation has extended the applications of evoked potentials to neuropathic pain disorders. Knowledge of the effects of motor programming, paired stimulations, and simultaneous stimulation of adjacent somatic territories has broadened SEP use in movement disorders. The recording of high-frequency cortical oscillations evoked by peripheral nerve stimulation gives access to the functioning of SI area neuronal circuitry. SEPs complement electro-neuro-myography in patients with neuropathies and radiculopathies, spinal cord and hemispheric lesions, and coma. Neuroimaging has overtaken SEPs in detecting and localizing central nervous system lesions, but SEPs still permit assessment of somatosensory and pain disorders that remain unexplained by anatomical investigations.

Influence of V2 vasopressin receptor agonist, 1-dezamino-8-D-arginine-vasopressin, DAVP, on a sensitivity disorders in stroke patients

Somatosensory disorders often developed after a stroke. It is known that they affect the outcome of the disease negatively. We analyzed the effects of vasopressin in correction of sensitivity disorders in stroke patients. Treatment received 15 patients with strokes from 41 to 67 years old in most cases with remote consequences of stroke. 13 patients had survived ischemic stroke, 2 patients - hemorrhagic stroke. V2 vasopressin receptor agonist, 1-dezamino-8-D-arginine-vasopressin, DDAVP, were injected intranasal for 2 weeks. DDAVP was effective in 73 % of cases. The therapeutic effect of neuropeptide manifested in decreasing symptoms of pain disorders, temperature and tactile sensitivity. The total intensity of surface and deep sensitivity disorders decreased. Aggregate severity of all types of disorders of sensitivity was significantly decreased after treatment. Thus, DDAVP may be used as monotherapy in patients with strokes and with central sensitivity disorders.