Three techniques to produce experimental spinal cord injuries in the rat are compared; 1) the weight dropping method, 2) the aneurysm clip compression method and 3) the extradural balloon compression method. In principle, different forces were used in technique one, while a constant force for different durations is maintained in techniques two and three. The relationship between these different types of injuries and subsequent clinical recovery was assessed quantitatively by the inclined plane method of Rivlin and Tator. The weight dropping technique was found unreliable for experimental spinal cord injury in the rat while the aneurysm clip compression technique resulted in consistent cord injuries with respect to subsequent clinical recovery. The extradural balloon compression method invariably resulted in complete recovery after three and five minutes but no recovery after seven minutes of 0.1 cc air inflated balloon compression of the cord indicating a steep dose — response curve. However, using a 0.2 cc air inflated balloon, no recovery was noted after one minute compression. The major factor in the pathogenesis of spinal cord injury produced by the weight dropping technique is believed to be mechanical, while both mechanical and vascular factors seem to operate in the clip and balloon compression techniques.

We describe a computer program which facilitates the analysis of a series of C.T. scans made while a stereotaxic frame is fixed to the patient.

The program has 2 modes of operation:

a) The operator may select a region and determine the three-dimensional frame coordinate.

b) The operator may select a set of frame coordinates and have the computer program display these at the appropriate sites on the C.T. scans. If these sites are the positions of depth electrodes, then a recording of the epileptic spike activity may be displayed at the appropriate sites on the scans.

The muscles of four infants with cerebro-hepato-renal (Zellweger) syndrome were studied during life and/or at necropsy. A mitochondrial myopathy was demonstrated, similar to mitochondrial alterations demonstrated in liver and brain in this disease. Muscle fibers with red-staining subsarcolemmal aggregates were identified with Gomori trichome stain in two cases. Subsarcolemmal and intermyofibrillar zones of increased concentrations of NADH-TR, SDH, and cytochrome-c-oxidase activity were demonstrated histochemically in all four cases. Degenerative and cytoarchitectural changes in muscle fibers were not found. Ultrastructural studies showed large aggregates of mitochondria and increased lipid in the subsarcolemmal and intermyofibrillar spaces. Degenerative changes in mitochondria and lipid also were demonstrated, but paracrystalline inclusions were not seen. The distribution of these changes was not uniform between patients or between different muscles in the same patient. The diaphragm was affected more severely than proximal or distal muscles of the extremities. Direct involvement of muscle mitochondria in this disease may interfere with energy metabolism and contribute to the clinical findings of hypotonia, weakness, and respiratory insufficiency. The muscle biopsy with histochemistry and electron microscopy may be used as a diagnostic adjunct in suspected cases, but the variation encountered dictates caution in the interpretation of negative findings.

Thirty-six patients with suspected or myelographically proven radiculopathies were investigated with motor and sensory conductions, F-waves, needle electromyography, and somatosensory evoked potentials (SEPs). SEPs were elicited by cutaneous nerve stimulation representative of input from individual cervical and lumbosacral dorsal roots. A myelographic defect was present in 83% of 30 patients who had myelograms. Overall 78% of patients had one or more abnormal electrophysiologic tests, the needle EMG giving the best diagnostic yield (75%). F-waves and SEPs were abnormal in 43% and 57% of cases respectively. Motor deficit correlated best with abnormal EMGs, whilst abnormal SEPs occurred most frequently when sensory deficit predominated. Prolonged latency of the SEP occurred rarely, reduced amplitude or abnormal morphology being the most useful characteristics. SEPs evoked by cutaneous nerve stimulation are a useful addition to conventionally available electrophysiological methods of evaluating radiculopathies, especially in the absence of motor deficit.

Delays of auditory perception at three frequencies were measured in 30 multiple sclerosis patients using a pscyhophysical technique. Nineteen patients had abnormal delays at one or more tone frequencies, though 15 had normal audiograms at those frequencies. In addition, auditory acuity for left-right asynchrony was abnormally poor in 13 patients, 9 of whom had normal audiograms. Such delays of auditory perception within a restricted frequency band may provide a partial explanation for degraded speech comprehension in some multiple sclerosis patients.

Twenty patients with hemifacial spasm were treated between February 1980 and June 1981. All presented with typical disabling unilateral contractions of the face. Computerized Tomographic Scan and angiograms ruled out structural mass lesions. All patients underwent posterior fossa microsurgical relocation of a vessel from the root entry zone of the facial nerve. An offending arterial loop was found in each case. Nineteen patients are free of symptoms and the remaining one is improved. One patient has permanent loss of hearing and two developed mild facial weakness. There has been no recurrence in 18 months follow up. These results give further support to the theory that hemifacial spasm is an affliction of the seventh nerve in the cerebello-pontine angle, most commonly caused by vascular cross compression at the root entry zone. Surgical relocation of the offending vessel relieves the symptoms and there appears to be no recurrence. This procedure is not difficult and carries acceptable risk for the patient with this disabling condition.

Two cases of intradural disc rupture with cauda equina compression are reported. Myelography demonstrated complete block and at surgery intradural fragments of sequestrated disc material were found. The pathogenesis of this condition is reviewed and our recommendation for management is presented.

The efficacy of intravenous phenytoin for the treatment of status epilepticus is related to the rapid entry of phenytoin into brain parenchyma. There is no information concerning the correlation between phenytoin serum and CSF concentrations in children, and the application of CSF data to clinical use. We report 7 children (2–11 yrs) who were treated or exposed to phenytoin in doses between 10.5–230 mg/kg. Lumbar puncture was performed 9 times in 6 of the patients. In one patient, an intraventricular catheter permitted successive assessment of CSF phenytoin concentrations. The ratio of CSF/serum phenytoin concentrations was 0.16 ± 0.08, with gradual increase over the first 8 hours as the serum phenytoin concentration decreased. There was good correlation between therapeutic outcome and CSF phenytoin levels higher than 2 mcg/ml. In one patient the coma state secondary to phenytoin intoxication was associated with high CSF concentration (6 mcg/ml).

The clinical and EEG findings were reviewed for 270 juvenile children from the Montreal Children’s Hospital Diabetic Clinic in an attempt to correlate the EEG findings at the onset of diabetes mellitus with the future risk of having a convulsion with a hypoglycemic reaction. Compared to a non-diabetic control population, the number of epileptiform EEG abnormalities was significantly increased in the initial EEG of diabetic patients who later had a hypoglycemic convulsion. The initial epiliptiform EEG did not help to differentiate those diabetics with recurrent hypoglycemic induced convulsions from diabetics who would have only a single convulsion.

A unique case of Huntington’s disease is reported because of the extremely early onset and death, and the atypical mode of presentation including severe behavioural problems and a negative family history. Although rare, Huntington’s disease must be considered along with the established degenerative disorders of white and gray matter peculiar to the pediatric population when one examines an infant or child with progressive motor deterioration, rigidity, mental retardation and behavioural abnormalities. Computed tomography is a reliable and non-invasive method of establishing the diagnosis during life.

A 79 year old male acutely developed a Brown-Sequard syndrome two weeks following resection of renal cell carcinoma. The subsequent clinical course was marked by subacute progression of spinal cord signs. Pathologic studies showed extensive multifocal spinal cord necrosis that could not be attributed to vascular occlusion or to vasculitis. This case appears to be a rare example of paraneoplastic subacute necrotic myelopathy.

Seventeen years before the Scharrers demonstrated neurosecretory activity of neurons within the brains of vertebrates and invertebrates and convinced the scientific world of the existence of a neuroendocrine system, Carl Caskey Speidel (1917) had identified glandular neurons in the spinal cord of the skate, postulated a neurosecretory function, and performed experiments to prove his hypothesis. The correct conclusions that he formulated from morphologic observations were not believed by biologists until ‘proved’ by the Scharrers, who acknowledged his pioneering contributions. The Scharrers studied many species and even demonstrated neurosecretion in nemertine worms, now believed to be closely related to the ancestors of all vertebrates. Evolutionary theorists had speculated on neuroglandular function as early as 1900, and the contributions of comparative neuroanatomists to this field have resulted in a major medical advance.