The first section of this article deals with specific anatomic and pathophysiologic factors which contribute to a poor EEG localization of the interictal epileptic abnormality and to the unreliable seizure onset localization commonly reported in patients with frontal lobe epilepsy. The localizing effectiveness of long term EEG monitoring was reviewed in four different groups of frontal lobe epileptic patients who underwent preoperative EEG investigation with extracranial and intracranial electrodes. The results of this study reveal a continuum distribution of interictal epileptic disturbances, ranging from focal abnormalities to lobar or multi-lobar epileptogenesis. A frontal lobe localization of the seizure generator based on ictal recordings obtained with extracranial electrodes is rather poor and much more reliable results can be obtained by depth-electroencephalography.

Visual hallucinations of remarkable intensity began shortly after intravenous atropine and persisted for 11 days. They were present only when the eyes were closed and were associated with heightened dreaming and disturbed sleep. The patient remained lucid and described his experiences to his attendants. Our patient's hallucinations bore some resemblance to hypnagogic hallucinations and this became the basis for the hypothesis that the hallucinations originated in the sleep-dream system of the brain stem. It is speculated that a similar site — a metabolic locus minoris resistentiae may play a part in other types of visual hallucinations and in delirium.

Venous angiomas (developmental venous anomalies) are vascular malformations increasingly recognized in general neurosurgical or neurological practice. They are associated with intracranial hemorrhage, seizures, or progressive neurological deficits or found as incidental findings in patients who present with headaches or have neuroimaging studies for investigation of unrelated neurological disorders. Since venous angiomas drain normal cerebral tissue within a functionally normal arterial territory, resection can lead to venous infarction. This report studies 27 patients with venous angiomas, all of whom had conservative treatment. The venous angioma was considered to be responsible for the onset of neurological symptoms in 14 patients (7 with hemorrhage, 3 with hemorrhage and seizures, 2 with seizures, one with an extrapyramidal movement disorder, and one with motor deficit). Thirteen patients had incidental lesions (8 with headache, and 5 with unrelated neurological symptoms). Ten venous angiomas were in the posterior fossa; seven in the cerebellum. Location did not correlate with symptomatic presentation. No patient with hemorrhage required surgical evacuation of the hematoma. No patient died or had significant morbidity during the follow-up interval (mean of 3.7 years). Venous angiomas are low flow, low resistance vascular malformations, many of which are not associated with neurological sequelae. Our series supports the concept that surgical removal or radiosurgical obliteration should not be performed unless a patient has a second life threatening hemorrhage.

The value of CT as a routine screening procedure in the investigation of cognitive impairment is being increasingly challenged. To address this issue, we reviewed the records of 175 patients with intellectual deficits admitted to a Behavioural Neurology Unit over a two-year period. In the vast majority of cases, ie. 82%, the CT served essentially to confirm the clinical impression and added no new diagnostic information that impacted the management of the presenting problem. In 15% of cases the CT scan was helpful for diagnosis, especially in the differentiation between Alzheimer's disease and multi-infarct dementia.

Patients with Myotonic Dystrophy (MyD) frequently suffer from a dysfunction of the primary sensory pathways, as documented by abnormalities of short-latency evoked potentials. Impairment of intellectual functions has been less extensively investigated. Short-latency brainstem auditory evoked potentials (BAEPs) as well as long-latency auditory event-related potentials (ERPs) were recorded from 5 female and 6 male patients affected by MyD. A simple discrimination (“oddball”) paradigm was used to record ERPs to tones from Fz, Cz, Pz. Both BAEPs and ERPs were significantly altered as compared to normals. BAEP abnormalities were detected in 9 patients and ERP components N2 and P3 were delayed or absent for all patients, who nonetheless correctly discriminated between tones. These data indicate that CNS dysfunction in MyD involves not only primary sensory systems but also neural mechanisms underlying cognitive events and ERP generation.

The anticonvulsant effects of amitriptyline, imipramine, nortriptyline and desipramine were tested against focal and generalized seizures, triggered from either the amygdala or the cortex in fully kindled rats. Tests were administered on a 72- or a 24-hour schedule. Significant seizure suppression was achieved with only one drug, amitriptyline, and it occurred only at toxic or near-toxic doses. The differential, low-dose suppression of amygdala-kindled seizures, reported in earlier studies, was not seen in the present experiments. It may occur only in the short-interval test paradigms used by previous experimenters.

Two novel reversible enzyme inhibitors involved in monoamine metabolism are described. The novel and reversible inhibitors are the catechol-O-methyl-transferase (COMT) inhibitor, Ro 40-7592 (3,4-dihydroxy-4'-methyl-5-nitrobenzophenone), and the monoamine oxidase type-B (MAO-B) inhibitor, Ro 19-6327 (N-(2-aminoethyl)-5-chloro-2-pyridine carboxamide HC1). These may be of special therapeutic benefit in Parkinson's and Alzheimer's diseases.

The concept of epileptogenic zone is defined as a large area of cortical neurons arranged in concentric circles of variable degrees of epileptogenicity. This is particularly so in frontal lobe epilepsy since the interictal and ictal epileptic abnormalities are poorly localized, often absent and at times misleading in terms of localization. In temporal lobe epilepsy, the epileptogenic zones may be more restricted.

The motor representation of the body musculature was studied in 11 adult mice by using ICMS. The motor responses elicited from both granular and agranular cortical fields showed that the mouse motor cortex is topographically organized; however, within the representation of individual body-parts the movements are multiply represented. In addition, several sites were encountered where more than one movement was elicited at the same stimulus threshold. The locations of pyramidal cells contributing axons to the pyramidal tract were examined by means of retrograde tracing with HRP injected into the cervical enlargement. This procedure labeled neurons only in lamina V in granular and agranular cortical fields. The similarities between the organization of motor cortex demonstrated in this study and the organization in the rat suggest that the rat and mouse share a common plan of rodent motor cortical organization.

The safety and efficacy of Sinemet® CR, a controlled-release formulation of carbidopa/levodopa, were investigated in a three year, open-label trial involving 18 parkinsonian patients with fluctuating motor response. The average daily levodopa dosing frequency did not change significantly during long-term treatment. Efficacy measures generally revealed a gradual progression of parkinsonian disability. Patient diaries of motor fluctuations revealed relative stability of time “on” but with a tendency toward increased time “on with dyskinesias” over the 36 month followup period. There were no adverse laboratory results deemed to be related to Sinemet® CR and no unexpected side effects were observed.

Amantadine hydrochloride (AH) was administered (200 mg/day) for more than three months to 17 patients with Friedreich's ataxia (FA) and to 12 patients with olivopontocerebellar atrophies (OPCA) in an open clinical trial. Reaction time (RT) and movement time (MT) with the right and left hand were measured before and after treatment. A striking improvement on both RT and MT was observed in the OPCA group (on seven out of eight measures), whereas in the FA patients improvement was seen only in two out of four MT measures with no improvement in RT. Both groups had low levels of homovanillic acid (HVA) in their cerebrospinal fluid before treatment, relative to their controls. However, improvement with AH was not related to HVA levels.

Mitral valve prolapse has been associated with an increased risk of transient or lasting ischemic events. Recurrence is uncommon after initiation of antiplatelet or anticoagulant therapy. In this communication we report two patients, both female, who had mitral valve prolapse as the major risk factor for cerebrovascular disease and who developed cerebral infarction despite anticoagulation. The cerebral infarctions were bilateral and extensive in one patient and led to the patient's death. In the second case, three infarctions resulted in moderate disability.

In a recent report on the clinical and pathological features of Guamanian ALS/PD and post-encephalitic parkinsonism/ALS a number of similarities were described, notably in the distribution of neurofibrillary tangles throughout the nervous system. In this account additional pathological features which these disorders share (and which differ from classical ALS, Parkinson's and Alzheimer's diseases) are described. These include atrophy of the globus pallidus and the entire substantia nigra, viz. pars compacta and pars reticulata. Moreover, neither Lewy bodies nor senile plaques are features of the Guamanian and post-encephalitic disorders. The significance of these observations and their relationship, more generally, to parkinsonism, ALS and dementia are discussed.

An introduction to the clinical study of postrolandic epileptic seizures. We reviewed, in 145 epilectics studied with SEEG, 800 clinical and electrographic seizures originating from the post-rolandic areas (590 spontaneous Sz and 260 induced by stimulation). The intra-cranial electrodes were implanted using a technique described by Talairach et al. (1974). Seizure onsets were recorded in the centro-parietal region (64 patients) in the partietal49 and in the occipital region.15 Additionally in 15 patients, mixed Sz onset were recorded. One hundred and eight (108) patients underwent surgical removal of their epileptic focus. (69 on the right, 39 on left.) 65% were cured (Sz free or occas Sz, f/up 3 years). The main ictal cal features are discussed. Emphasis is placed on the role of the operculo-insular cortex in the functional organization in man, based on Sz arising from the supra-temporal (fronto-pariental) cortex. The study of the pattern of onset and spread of seizures originating in the post-rolandic areas and of their clinical correlates allow a topographic differential diagnosis.

The cause of the toxic mussel poisoning episode in 1987 was traced to a plankton-produced excitotoxin, domoic acid. Experiments were undertaken to quantitate the degree to which blood-borne domoic acid can permeate the microvasculature to enter the brain. Pentobarbital-anesthetized, adult rats received an i.v. injection of 3H-domoic acid which was permitted to circulate for 3-60 min. Transfer constants (Ki) describing blood-to-brain diffusion of tracer were calculated from analysis of the relationship between brain vs plasma radioactivity with time. Mean values (mL.g-1.s-1 x 106) for permeation into 7 brain regions (n = 10 rats) ranged from 1.60 ± 0.13 (SE) to 1.86 ± 0.33 (cortex, ponsmedulla respectively), and carrier transport or regional selectivity in uptake were not evident. Nephrectomy prior to domoic acid injection resulted in the elevation of circulating plasma tracer level and brain uptake. The Ki values are comparable to those for other polar compounds such as sucrose, and indicate that the blood-brain barrier greatly limits the amount of toxin that enters the brain. Together with absorbed dosage, integrity of the cerebrovascular barrier and normal kidney function are important to the outcome of accidentally ingesting domoic acid.

Inter-observer agreement was evaluated for twelve items used in the neurological assessment of comatose children. Data were obtained prospectively on fifteen patients examined independently by two observers in a double-blind fashion. Observer variability was measured by using the Disagreement Rate and Kappa statistic. The Disagreement Rate ranged from 0.01 to 0.12 for all items. Values for Kappa statistic were generally in accordance with those for Disagreement Rate. The data suggest fair to almost perfect inter-observer agreement for the items used to assess comatose children in this study.

It is well known that various markers of the cholinergic synapse are altered in Alzheimer's Disease. Much interest is currently focussing on the evaluation of the possible efficacy of certain growth factors, especially nerve growth factor (NGF), to reduce or reverse cholinergic neuronal losses. Here we report that other growth factors (epidermal growth factor and insulin-like growth factor I) and a lymphokine, interleukin-2, are able to block acetylcholine release in the rat hippocampus. This suggests that while certain growth factors like NGF may have positive effects on the cholinergic neuron, others may act as “negative” factors on this neuronal population.

We present clinical and pathologic data on four previously unreported familial ALS pedigrees and review and analyze by descriptive and exploratory statistical techniques all published cases of familial ALS (1850-1989). In contrast to the age-dependent incidence of sporadic ALS, the age of onset of familial ALS is normally distributed about a mean of 45.7 years (std. dev. 11.3 years). Survival curves for the familial ALS data also demonstrate a skewed distribution with a median survival time of 24 months with 74% surviving at 12 months, 48% at 24 months and 23% surviving at 60 months. The patient characteristics of age at onset of disease, sex and focus of disease onset are unrelated variables and age at onset of disease is the only predictor of survival (Cox's proportional hazard model, chi-square 14.74, p = 0.0001). By applying accelerated failure time models with a log-normal baseline distribution, estimated probabilities for survival adjusted by age at onset were calculated. It was found that the older the age at disease onset, the shorter the survival.

Cerebrovascular accidents due to Moyamoya disease, a disorder characterized by arterial stenosis at the base of the brain accompanied by typical net-like collateral vessels, occurred in two young Japanese women with Graves' disease when they were in thyrotoxicosis. In one patient, a second attack of cerebral infarction occurred with the recurrence of thyrotoxicosis. Association of Moyamoya disease and Graves' thyrotoxicosis is rare and the pathegenetic relationship is discussed.

The clinical functions of the posterior columns of the spinal cord and the signs of disease of these structures have been debated for years. Todd in 1847 and Schiff in 1858 knew the functions of the posterior columns and 10 years later Brown-Sequard knew as well. Reynolds, Romberg, and Duchenne, each described a posterior column syndrome based on a disease in which the primary lesion was not in the posterior columns. In the last 150 years almost every white matter structure of the cord has been credited with serving the sensations that we now know are a function of the posterior columns. Vibration, joint position and movement as well as discriminatory touch each seem to be served by separate fibres of the posterior columns and medial lemniscus. There is evidence of this in cat and man. These sensations may be lost individually, totally, or in certain stereotyped combinations. Vibration or joint sense is commonly lost alone. When a discriminatory touch sensation is lost with one other sense, it is almost inevitably joint position sense. Absent discriminatory touch and vibration sense with normal joint position sense appears to be unknown. This functional separation continues into the thalamus. At the highest level there is no evidence that vibration sense has any conscious somatosensory cortical affiliation, while joint position and discriminatory touch senses definitely do.