Pre-movement motor excitability is reduced ipsilateral to low force pinch grips.

Motor excitability ipsilateral to pinch grips was investigated during the pre-movement period. Subjects performed right-handed phasic pinch grips with 2% or 20% maximum voluntary contraction (MVC) in response to a visual go-signal. Transcranial magnetic stimulation (TMS) was applied over the right motor cortex at various intervals before the go-signal and 100 msec after movement onset. Motor evoked potentials were recorded from the relaxed left first dorsal interosseous muscle. Immediately prior to and during 2% MVC pinch grips, MEP amplitudes were reduced. In contrast, MEPs obtained by transcranial electrical stimulation tended to be increased, indicating that MEP decreases are mediated at a cortical level. Before and during 20% MVC pinch grips MEP amplitudes were enhanced. TMS delayed reaction time if applied close to the go-signal. We conclude that the motor cortex ipsilateral to low force movements is inhibited prior to and during movement.

Upper extremity function after wrist arthrodesis.

Several studies have examined the normal range of wrist motion used to accomplish activities of daily living. Little information is present, however, on what functional limitations might be experienced by patients actually undergoing formal wrist arthrodesis. This study undertook comprehensive functional evaluation of 23 patients who underwent wrist arthrodesis for post-traumatic conditions. Follow-up evaluation averaged 54 months and consisted of a clinical questionnaire, the Jebsen Hand Function Test, and a functional rating devised by Buck-Gramcko/Lohmann. Fifteen of the 23 patients returned to their original jobs, and all patients noted that although the vast majority of tasks could still be performed, these tasks were undertaken in a modified fashion. The most difficult daily tasks for patients with a wrist arthrodesis to perform involved perineal care and manipulating the hand in tight spaces. The Jebsen Hand Function Test demonstrated a 64% task completion rate with the fused wrist compared to a 78% task completion rate for the normal wrist. The Buck-Gramcko/Lohmann evaluations demonstrated an average score of 8.3 out of a possible 10. Patients who have undergone wrist arthrodesis can accomplish most activities of daily living and other functional requirements, although some adaptation to accomplish these tasks is required.

The relationship between visual seizures and visual evoked potentials.

We have studied a patient (pt) in status epilepticus with visual seizures (szs) arising focally from the right occipital area and have recorded the visual evoked potential (VEP) to three different stimuli under three different conditions (during, between and with no szs). The pt experienced "sparkling" in the contralateral visual field as the sz and the intensity of the "sparkling" was directly related to the frequency of the ictal activity recorded on the EEG. During the szs the VEPs could still be recorded, but the amplitude of the P100 was higher on the contralateral side with pattern reversal (PR) stimuli, and with flashes (FL) the positive peak after the P100 was less evident on the ipsilateral side. Latencies to these latter two positivities were generally shorter than in normals, with much greater standard deviations ipsilaterally with FL and contralaterally with PR, especially during the actual szs. The relationship between VEP generation and visual sz phenomena is discussed.