This review describes the recent advances in slow infections of the nervous system emphasizing the pathogenetic aspects of these diseases. A theoretical model for the pathogenesis of subacute sclerosing panencephalitis (SSPE) is proposed, illustrating the factors that may affect host response to the measles virus and allow it to persist and produce the panencephalitis. The isolation of an oncogenic virus from progressive multifocal leukoencephalopathy (PML) has implications in the consideration of a viral etiology for some brain tumors. The agent responsible for the transmissibility of kuru and Creutzfeldt-Jakob disease (CJD) remains uncharacterized despite recent interest in viroids and abnormalities in replication of cell membranes. The epidemiological data on multiple sclerosis suggests an exposure to an infectious agent at an early age of life modified by the host response. No specific agent has been consistently associated with multiple sclerosis. Amyotrophic lateral sclerosis (ALS), Parkinson’s disease, Mollare’s meningitis and Behcet’s disease are other examples where a virus is suspect but unproven. The ability of viruses to persist in the host for months to years has linked many chronic neurologic diseases to an infectious agent, enlarging the spectrum of disease caused by viruses.

Gray and white matter were obtained during neurosurgical therapy of focal epilepsy from 17 patients. In 10 patients, receiving only phenobarbital, the drug was uniformly distributed between gray and white matter. Phenytoin concentrations averaged 1.4-fold greater in white matter than in gray matter when expressed per gram wet weight of tissue. The gray matter/plasma ratio of phenytoin was approximately 2-fold greater than that of phenobarbital. Carbamazepine levels were also slightly greater in white matter The data revealed wide differences between drugs in the relative concentrations in gray and white matter, which must be taken into account in any quantitative studies of anticonvulsant drug levels in the brain.

The treatment of high blood pressure prevents death from congestive heart failure, hypertensive nephropathy, and encephalopathy, and strokes from cerebral arteriolar disease (lacunes, hemorrhage from micro-aneurysms). However, atherosclerosis, manifested as coronary artery disease, is just as frequent a cause of death in well-controlled hypertensives as in poorly-controlled patients. Increasing evidence suggests that increased blood velocity, by causing turbulence and high shear rates at the endothelial surface of arteries, may be important in the pathogenesis of atherosclerosis. Turbulence has been observed in cerebral berry aneurysms. In order to measure the effects of antihypertensive agents on blood velocity, a new method of analysing Doppler ultrasound velocity recordings has been developed. Studies in Rhesus monkeys show the following: In doses which reduce diastolic pressure by 13-28%, propranolol decreased mean blood velocity (MV) by 17%, clonidine decreased MV by 14%, while methyldopa increased MV 12%, and hydralazine increased MV by 52%. (p < .00001). It is hypothesized that enlargement of berry aneurysms, the progression of cerebral atherosclerosis, and embolism from carotid lesions might all be decreased by the selection of antihypertensive agents which decrease blood velocity.

Fifty-six patients with 63 aneurysms were selected from a larger group of patients because they had at least one angiographic and one CT scan study. A total of 102 CT scans and 136 angiograms were analyzed. In five patients the aneurysm was visualized on the CT scan. There was a tendency for the location of the subarachnoid hemorrhage and intracerebral hematomas visualized on the CT scans to correlate with the site of the aneurysm as seen on the angiogram. The CT scan was useful in demonstrating the evolution of hydrocephalus and in differentiating hematoma from edema. The patients with normal CT scans were more likely to have good neurological grades. No single angiographic or CT scan feature correlated significantly with survival at lower than the 5 percent level.

Bilateral anteromesial or orbital cortical lesions do not affect sequential pattern of amygdaloid seizure development. However, orbital cortex lesions appear to significantly participate in the elaboration of a Stage 6 seizure pattern.

Amygdaloid kindling ipsilateral to the side of anterodorsal cortical lesion or in animals with the same bilateral lesion appears to predispose them for the development of spontaneous, non-convulsive (partial complex) seizures. It also significantly modifies clinical ictal patterns with practical omission of Stages 2, 3 and 5, and largely lateralizes AD propagation to the stimulated hemisphere.

The latter two features are strikingly reminiscent of the electroclinical manifestations of secondary site AM kindling in intact animals or AM kindling in animals with forebrain commissure bisection.

Nonconvulsive (partial complex) status epilepticus was readily arrested by placement of electrolytic lesions ipsilateral to the AM stimulation, suggesting that MRF is essential for the perpetuation of the recurrent spontaneous seizure.

Finally, the presence and absence of positive and negative aftereffects respectively, in animals with anterodorsal cortical lesion is consistent with the view that transfer and interference effects are mediated through the brain stem and forebrain commissures respectively.

The propagation velocities and conduction times of nerve impulses responsible for muscle F-waves were measured in the proximal segments of 60 normal posterior tibial nerves and of 41 normal peroneal nerves. The results were compared with those of 25 patients having confirmed lumbosacral root compression due to disc degeneration. Using the peroneal nerve, 65 per cent of patients had a prolonged proximal conduction time; a similar abnormality was found in 56 per cent of patients when the posterior tibial nerve was studied. The yield of positive results rose to 85 per cent and 76 per cent respectively when the M- and F-latencies in given individuals were compared. It was also shown that in normal subjects the F-response has a longer latency, and slower conduction velocity than the H-reflex when both are obtained using the same stimulating and recording sites, in patients in whom the ankle jerks and H-reflexes are absent, the F-waves may still be recorded, indicating that the latter are mediated through motor fibers

The ribonuclease activity of cerebrospinal fluid of 219 patients was studied. The normal level was 269 ±95 units/ml. Consistent elevations above 550 units/ml were found in. 1 Chronic cerebrovascular disease, 2 Spinal cord compression; 3. Tumors. The molecular weights of the ribonucleases in the cerebrospinal fluid are approximately 33,000; 21,000 and 15,000, the major species is the one with m w. 33,000.

Although the increase in the CSF ribonuclease activity is not disease specific, the measurement has provided corroborative help in cases when the CSF protein is normal.

The increase in CSF RNAase is not due to red or white blood cells and the immunologie data suggest that the CSF enzyme activity is derived from the blood stream Further studies are necessary to rule out a nerve cell origin of the CSF ribonuclease activity.

About 10% of patients consulting a family practitioner have neurological complaints, and about 2% ultimately receive a neurological diagnosis As it is not possible to train enough neurologists for these patients, graduating medical students must be competent and confident in assessing neurological problems, particularly those that are common, treatable or require emergency management.

An evaluation was made of the neurological problems commonly seen in family practice, the difficulties in managing neurological problems by the family practitioner and the criteria for referral to a neurologist. To evaluate the teaching of medical students and house staff, the types of problems seen in a teaching hospital neurology service were examined.

As a result of this study an approach to the training of physicians is outlined to assist them to handle confidently and competently the neurological problems they will see in daily practice.

A 65-year-old female patient with Paget’s disease displayed dementia, a bilateral Parkinsonian syndrome, gait ataxia, bilateral grasp reflex of the feet, urinary incontinence and a left hemicerebellar syndrome. She had a marked basilar impression; the radionuclide cisterno gram was suggestive of a communicating hydrocephalus with ventricular dilatation. After a shunting procedure there was improvement in both neurological and mental function.