Quantitative assessment of position sense at the ankle: a functional approach.

We studied position sense at the ankle in 22 normal subjects to develop a functionally meaningful method of identifying mild position sense loss in individuals with suspected posterior column disease. Subjects were asked to match the angular displacement of a passively positioned reference foot. The subjects tried to improve performance by training sessions and visual feedback during the task. The subjects made accurate matches over a wide range of positions, with an average error of about 3 degrees. These methods can be used to provide a sensitive assessment of proprioception.

Recovery from partial deafferentation increases 2-deoxyglucose uptake in distant spinal segments.

2-Deoxy[14C]glucose autoradiography was used to study the responsiveness of the partially deafferented rat spinal cord to electrical stimulation of low-threshold afferent fibers. Unilateral extradural dorsal rhizotomies were carried out at L3 to S2, sparing L5. Postoperative sensory deficits were appropriate to the extent of the lesion. Acute, 7 day, and 14 to 20 day postrhizotomy animals and unoperated controls were anesthetized prior to isotope injection and electrical stimulation of Ia fibers in the L5 root. Quantitative densitometry was carried out on enlarged autoradiographs, subdividing the spinal gray matter into laminar divisions drawn from the corresponding stained sections. Optical densities from stimulated and unstimulated sides were compared using paired t tests for each experimental group at each lumbosacral segment (L1 to S2) and at T13 for the day 14 to 20 animals. This procedure provided an objective basis for statistical comparisons between homologous areas even where the differences in density were small. Unoperated animals showed activation in 11 of 23 dorsal horn zones extending to L2 and never involving the base of the dorsal horn (lamina V). Acute and day 7 groups did not appreciably differ from the control group except for activation of lamina V within the L4 segment. In the most delayed group, 18 dorsal horn regions were activated, extending to L1 with an additional zone in T13 . Lamina V contained significant labeling in three segments. In no group was there increased labeling of the ventral horn. The results are interpreted as showing that stimulus-related, neural activity increases after a 2-week delay in regions of spinal cord distant from the normal zone of significant metabolic change. This increase in neural activity during recovery is discussed in relation to time-dependent electrophysiologic, structural, and metabolic responses to deafferentation. The longitudinal spread of dorsal horn activation by preserved afferent fibers in the spared root may facilitate more effective central transmission of sensory information.

Choreoballismus: a nonhemorrhagic complication of venous angiomas.

Choreoballismus, developing subacutely in a 48-year-old man, is reported for the first time as a complication of a cerebral venous angioma, demonstrated by computed tomography scanning and angiography. There was no apparent hemorrhage or mass effect from the angioma, which was located in the right caudate nucleus. The movement disorder, which did not respond to haloperidol alone, disappeared after the addition of clonazepam. The necessity for dual therapy implies that there was a disorder of more than one neurotransmitter system in this patient. The clinical and pathological features of these unusual vascular malformations are reviewed.

Cerebellar infarction: a clinical and CT study.

Seven patients with computed tomographic (CT) evidence of cerebellar infarction were found during review of all CT records over a 5-year period. CT demonstrated decreased density in 2 distinct anatomic areas, corresponding to the distribution of the posterior inferior cerebellar artery and the superior cerebellar artery. Some patients also had hydrocephalus and fourth ventricular effacement and displacement. The location and extent of infarction do not relate directly to the clinical outcome. Rapid deterioration of the patient's sensorium is the best indication for surgical decompression.

Endogenous myelin basic protein-serum factors (MBP-SFs) and anti-MBP antibodies in humans. Occurrence in sera of clinically well subjects and patients with multiple sclerosis.

Sera of normal subjects and patients wtih multiple sclerosis (MS) have been frequently found to contain picomolar quantities of endogenous myelin basic protein-serum factors (MBP-SFs). These serum factors, collectively representing a heterogeneous spectrum, were detected and measured by means of a competitive inhibition radioimmunoassay (RIA) designed to distinguish their respective binding affinities with anti-MBP reagent antiserum. Anti-MBP antibodies in these same normal and patient sera were also detected and their differing binding affinities determined. In general, when sera of normal subjects were found to contain free MBP-SFs, the reagent anti-MBP antibodies in the reagent antiserum used to detect them were of relatively high binding affinity (8 X 10(8) M-1). When normal sera were found to contain free anti-MBP antibodies, the affinities of such antibodies were invariably lower (0.06-0.7 X 10(8) M-1). In contrast, sera of patients with active MS and exhibiting clinical fluctuations in their disease, infrequently contained high or medium high affinity MBP-SFs, whereas higher affinity anti-MBP antibodies were commonly detected. These patterns of MBP-SFs and anti-MBP antibodies in normal and MS human sera resemble those previously observed in studies of normal Lewis rats and rats developing experimental allergic encephalomyelitis (EAE). The findings here reported provide additional support for the view that circulating endogenous MBP-SFs may function as neuroautotolerogens that restrict expansion of MBP-reactive lymphoid cell clones having potentially injurious effector activity for central nervous system (CNS) tissue.

Sarcoid encephalopathy with diffuse inflammation and focal hydrocephalus shown by sequential CT.

Sequential computerized tomography (CT) was performed on a patient with seizures and an organic mental syndrome. Cerebral sarcoidosis was subsequently diagnosed on the basis of noncaseating granulomas in three organ systems. Cranial nerve palsies, hypothalamic dysfunction, and widespread disease were absent. An unusual neuroradiologic sequence of events indicated focal and asymmetric hydrocephalus, mass effect, ependymitis, diffuse breakdown of the blood-brain barrier, and periventricular white matter destruction. These findings have not been previously described together in a patient with sarcoid. With the advent of noninvasive CT, it is possible to perform serial investigations of encephalopathies of obscure origin. Findings similar to those in the present case should prompt a thorough search for subclinical systemic involvement by sarcoid.

Regeneration of motor axons in the rat sciatic nerve studied by labeling with axonally transported radioactive proteins.

Labeling regenerating axons with axonally transported radioactive proteins provides information about the location of the entire range of axons from the fastest growing ones to those which are trapped in the scar. We have used this technique to study the regeneration of motor axons in the rat sciatic nerve after a crush lesion. From 2 to 14 days after the crush the lumbar spinal cord was exposed by laminectomy and multiple injections of [3H]proline were made stereotactically in the ventral horn. Twenty-four hours later the nerves were removed and the distribution of radioactivity along the nerve was measured by liquid scintillation counting. There was a peak of radioactivity in the regenerating axons distal to the crush due to an accumulation of label in the tips of these axons. After a delay of 3.2 +/- 0.2 (S.E.) days, this peak advanced down the nerve at a rate of 3.0 +/- 0.1 (S.E.) mm/day. The leading edge of this peak, which marks the location of the endings of the most rapidly growing labeled fibers, moved down the nerve at a rate of 4.4 +/- 0.2 mm/day after a delay of 2.1 +/- 0.2 days; this is the same time course as that of the most rapidly regenerating sensory axons in the rat sciatic nerve, measured by the pinch test. Another peak of radioactivity at the crush site, presumed to represent the ends of unregenerated axons or misdirected sprouts, declined rapidly during the first week, and more slowly thereafter.