Applied neurophysiology
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Spinal cord stimulation, which has been shown to be beneficial in multiple sclerosis as well as in sustained spinal cord injury, works through modification of specific motor mechanisms. This modification occurs through regional recruitment of spinal cord activity in posterior aspects of the spinal cord. Substantial involvement of the placebo effect can be ruled out by noting the persistence of beneficial effects observed in spinal cord injury patients and by the fact that the effects are related only to depolarization of posterior structures of the spinal cord, rather than to perception of a 'tingling' sensation caused by spinal cord stimulation. Such a sensation can also occur when electrodes are over anterior or lateral structures of the spinal cord, when the stimulation is not effective in alleviating motor symptoms.
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The averaged electrical potentials evoked by the stimulation of the peripheral nerves were recorded with surface electrodes over the lumbosacral, lower thoracic and cervical spine and with epidurally placed electrodes in the cervical area. The waveforms of the lumbosacral and cervical spinal cord potentials show similar complexity reflecting peripheral and central generators. The larger negative wave with at least two components is followed by a slower positive deflection. Evoked potentials recorded over the cervical segments of the spinal cord with epidural electrodes are of much higher amplitude and more complex waveform than those recorded with surface electrodes.
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Applied neurophysiology · Jan 1980
Long-term follow-up study after pulvinotomy for intractable pain.
Pulvinotomy was performed on 42 cases with intractable pain. 19 cases survived for more than 1 year, the results were classified as follows: 4 were excellent, 4 good, 5 fair, and 4 were poor. The effects of the operation are discussed based on the disease. 2 cases, who survived for more than 1 year, suffered from the pain due to infiltration or metastasis of cancer, they died 22 and 14 months after the operation, respectively, but they had no intractable pain during the year before death. 14 cases who underwent CVD survived for more than 1 year. ⋯ After more than 1 year, 2 cases with atypical facial pain were considered as being either fair or poor, one (fair case) of whom still does routine housework and is not drug dependent. A case of causalgia has been free from pain for 5 years after the operation.
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Applied neurophysiology · Jan 1980
Experimental pain and transcutaneous electrical nerve stimulation at high frequency.
Transcutaneous electrical nerve stimulation (TENS) at high frequency and high intensity caused human pain threshold elevation for thermal stimuli only when thermal stimuli were applied at a site distal to the TENS electrodes. High-frequency TENS applied over the belly of m. biceps brachii did not cause a marked misestimation of elbow angle at any of the TENS intensities used. It is concluded that pain threshold elevation during high-frequency TENS is due to peripheral electrogenic blockade or fatigue of pain-mediating fibers. A minor effect of TENS on kinesthesia suggests a minor role of muscle afferents in mediating the effects of high-frequency TENS.
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Applied neurophysiology · Jan 1980
Case Reports Historical ArticleStereotactic evacuation of large intracerebral hematoma.
Despite the declining incidence of strokes, statistics regarding intracerebral hemorrhage indicate a relatively stable incidence in this form of cerebral insult over the past 20 years. Intracerebral hemorrhage accounts for 10% of all strokes, and is fatal to 50-60% of its victims. Until the advent of computer-assisted tomography, surgical intervention offered little benefit to patients suffering primary hemorrhage within the deep gray structures of the cerebral hemispheres. Technical advances in both diagnostic and therapeutic instrumentation now permit stereotactic subtotal evacuation of deep intracerebral hematomas.