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The neuroanatomic substrate of the alien hand syndrome has remained controversial due to the noncircumscribed nature of cerebral injuries present in most cases. There have been few cases studied in which damage was restricted to portions of the body of the callosum, and most of those involved surgical callosotomy for tumors or epilepsy. We report the case of a woman with a transient alien hand syndrome caused by a stroke limited to the middle and posterior portions of the body of the corpus callosum. This case provides supportive evidence for damage to the midbody of the corpus callosum as the anatomic basis of nondominant alien hand syndrome and conforms to a model of interhemispheric motor disconnection as the essential component of this unusual behavioral syndrome. This disconnection can occur with injuries involving interhemispheric premotor and motor fibers traveling in the midportion of the callosum in individuals with left hemisphere dominance for motor activities.

Two patients successfully treated for prostatic cancer developed a progressive neurologic syndrome beginning with loss of voluntary horizontal eye movements followed by severe, persistent muscle spasms of the face, jaw, and pharynx. Both had mild gait unsteadiness, and one exhibited facial and abdominal myoclonus. Extensive diagnostic studies, including MRIs of the brainstem (with and without contrast), were normal. CSF examination showed mild pleocytosis and elevated IgG. Quantitative eye movement recordings documented selective involvement of voluntary horizontal saccades with sparing of horizontal slow eye movements. Neither patient had antineuronal antibodies in the blood. Postmortem examination revealed perivascular chronic inflammatory cells and microglial infiltration of the pons and medulla. One patient also had perivascular infiltrates in both mesial temporal lobes. Neuronal loss was localized to the pontine tegmentum, the medullary sensory nuclei, and the cerebellum. Brainstem motor nuclei were preserved. The clinical and pathologic findings suggest an autoimmune process (probably paraneoplastic) with selective damage to a subpopulation of brainstem neurons critical for horizontal eye movements and recurrent inhibition of bulbar nuclei.

We routinely monitor invasive neuroradiologic carotid balloon test occlusions with continuous polygraph and quantitative EEG along with repeated detailed clinical examinations. Four of 17 consecutive cases showed changes during carotid occlusion. In one instance, an immediate delta increase was accompanied by slurred speech and aphasia. Another showed alpha attenuation without clinical change. A third patient had significant clinical change without EEG change. Nine of the 17 cases underwent permanent therapeutic carotid occlusion as treatment of an intracerebral vascular abnormality. Seven of these nine had no EEG or clinical changes during monitoring and have had no functional abnormalities on follow-up. The patient with focal alpha attenuation had an accidental balloon detachment but has had no functional or structural neurologic abnormalities. The patient with minor regional increased delta received a permanent carotid occlusion and went on to develop clinical signs 24 h later. We believe that continuous EEG monitoring and repeated clinical examinations provide useful ways of evaluating cerebral circulation during carotid test occlusions.

Median nerve somatosensory evoked potentials were recorded from exposed cerebral cortex during craniotomies. This technique is valuable when knowledge of the motor cortex location can influence surgical decisions about resection limits or biopsy sites. Two different recording techniques were compared: strips of electrodes and arrays of electrodes. The arrays recorded electrical potentials suitable for topographic mapping. We found that motor cortex could be identified more quickly when using the topographic mapping of SEPs from arrays. We conclude that topographic mapping of SEP from sensorimotor regions during craniotomies works well in general and can be done more quickly than the traditional electrode strip technique.