Quantification of EEG waves in healthy persons and patients with brain disorders [abstract]

The biological processes that give rise to many disorders of the brain such as schizophrenia, depression and epilepsy are yet to be clearly explained. The electroencephalograms (EEG) from patients with these disorders have been reported to exhibit "chaotic" properties. Coarse-grained correlation dimension (Dcg) has been found to be an effective tool in analyzing waveforms with chaotic properties. We therefore tested the hypothesis that the Dcg of the EEG of patients with the above disorders will be different from those of healthy volunteers. Twenty-five minutes of EEG recordings were obtained from different regions of the brain of 20 healthy volunteers, seven patients with schizophrenia, one with depression, and one with partial seizure. Each person's EEG was edited to obtain 51 seconds of artifact-free recording. A software was developed in-house and used to obtain estimates of the Dcg. A confidence interval for each of the 21 EEG electrode points was established for the healthy volunteers (control group). Compared to the control group, the Dcg measurements of some of the schizophrenics, of the depressed patients, and that of the epileptics showed significant differences (p< 0.005). The results of this study indicate that the Dcg of the EEG for some brain disorders may be of use in the diagnosis of these conditions. Given the preliminary nature of this study, further work with larger sample sizes will be necessary in order to determine the reliability and sensitivity of this method. (AU)

Increased BAEP latency and reduced brain cytochrome c oxidase activity observed in the Suzuki model of Alzheimer's disease [abstract]

Cytochrome c oxidase (COX), the terminal respiratory enzyme, is reported to be deficient and to exhibit reduced activity in a number of neurodegenerative disorders. The Alzheimer's rabbit model is based on the intracerebral injection of Holt's adjuvant, an aluminum salt solution. This model was used to compare the brain activity and the activity of brain COX in treated and controlled rabbits. Of a total of 26 New Zealand white rabbits, thirteen were injected intracerebrally with Holt's adjuvant solution, five with physiologically saline solution and the remainder were kept as controls. The auditory responses (BAEP) of the rabbits were monitored for 14 days before injections and 14 days thereafter. The animals were then sacrificed and brain mitochondrial extracts were used for SDS-PAGE analysis, difference spectra spectrophotometry and polarographic assays. The results of SDS-PAGE showed that there were no differences in the protein composition of the brain mitochondria of the three groups. Similarly, difference spectra (reduced minus oxidized, 400-630 nm) from both treated groups were identical to that of the control with characteristic maxima centered around 434, 550 and 604 nm. Polarographic assays, however, showed that while the enzyme from both treated groups displayed the characteristic biphasic kinetics, there was reduced activity in the enzymes from the brain of rabbits receiving the adjuvant but not the saline solution. This result is significant in light of the fact that several researchers have reported reduced activity of COX from Alzheimer's disease (AD) patients. Of particular significance, BAEP results reveal an increase in the interpeak latency between peaks III and V of the Holt's injected but not the saline injected or control rabbits. This latter result suggests that monitoring the BAEP might provide a simple non-invasive method for confirming AD. (AU)

Computed tomography in the examination of seizures at the University Hospital of the West Indies

A retropective evaluation of the Computed Tomography (CT) findings in three hundred and forty-four patients with seizures, presenting over a one-year period, was carried out to determine the value of this examination in the assessment of these patients. Eighty-four per cent of patients had non-contrast studies only. Of the remaining patients, two had contrast studies only and the rest had both non-contrast and contrast studies. All cerebal abnormalities detected on contrast studies were evident on on-contrast scans. Forty-two percent of all patients presenting seizures were found to have a demonstrable abnormality on CT. There was a greater detection rate in patients with seizures secondary to trauma, cerebrovascular incidents, infection, metabolic causes and suspected tumours. Computed tomography continues to have place in the evaluation of certian types of seizure patients. The routine use of intravenous contrast does not appear to be justifiable.(Au)

Tuberculous encephalopathy. A rare complication of pulmonary tuberculosis

A case of tuberculous encephalopathy, a rare form of neurotuberculosis, is reported in a 16-year-old girl who had pulmonary tuberculosis and extensive cerebral demyelination. The clinical, laboratory and pathological features of this entity are highlighted and the pathogenesis discussed.(Au)

Malignant meningioma with extension into the neck

One per cent of all brain tumours and twenty per cent of meningiomas eventually develop an extracranial extension. The least common site is the neck. We report a case of malignant meningioma with extension into the neck of a 39-year-old male.(Au)

Electrophysiological assessment of brain function in severe malnutrition - abstract

Brain function in severly malnourished children was assessed, using computer analysis of electroencephalographic (EEG) responses to photic driving at different frequencies during slow-wave sleep. Percentage power in the classical EEG broad-band domains was derived from temporo-occipital records. Ten malnourished infants (5 - 23 months), age and sex-matched with 10 healthy controls (CON), having no neurological involvement or previous malnutrition, were studied. The malnourished group was tested on admission (ADM) and on discharge (DIS) from hospital. A stronger mean peak response to photic driving for the narrow band spectra was observed for the malnourished group, but this difference did not attain a level of statistical significance. This observation indicates a reduced efficacy of inhibitory processes in the malnourished brain, a condition also observed in the brain of malnourished animals. Significant differences were, however, found in the alpha-1 band for the undriven EEG, and in the summed alpha/beta-1 power ratio while driving at 8 Hz, between the malnourished and control groups. ADM and DIS groups did not differ significantly in the trend towards reduction from ADM to DIS to CON. These findings indicate that, in malnutrition (1) EEG measures can index the deviation of brain function from normality, and (2) physical properties relating to brain function remain abnormal despite anthropometric catch-up (AU)

Multiple scherosis, tropical spastic paraparesis and HTLV-1 infection in Afro-Caribbean patients in the United Kingdom

Forty four consecutive patients of Afro-Caribbean origin resident in the United Kingdom (UK) were studied, based on a provisional diagnosis of myelopathy of unknown cause, tropical spastic paraparesis (TSP) or multiple scherosis (MS). Of 30 patients with progressive paraparesis 27 had serum antibodies to HTLV-1 and were classified as having TSP. Fourteen patients fulfilled the criteria for MS and none of 12 tested had HTLV-1 antibodies. All the TSP patients and nine of those with MS were born in West Indies. Five of the West Indian born MS patients had migrated to the UK after adolescence but the duration of residents in the UK before symptoms of MS developed was similar to those born in the UK (average 18 years). The features that differentiated MS from TSP patients, apart from HTLV-1 status, included clinical evidence of cranial nerve involvement, more extensive abnormalities on the brain and cervical cord MRI and asymmetry of the VEP latency increase, all of which were more frequent in the MS group. Of the three patients without a diagnosis one, born in the UK, had marked abnormalities on MRI of the brain indistinguishable from those seen in MS (AU)

Occult vascular malformations of the brain - abstract

Intracranial vascular malformations have been classically divided into four groups: arterio-venous malformations (AVMs), cavernous angiomas, venous angiomas and capillary telangiectasias. The AVMs are the best documented of these lesions and are readily characterized with cerebral angiography. The other malformations have previously been rarely diagnosed during life as they are usually not seen on cerebral angiograms. Recently, however, with the use of advanced neuro-imaging techniques these lesions have been increasingly recognized in association with intracranial haemorrhage and epilepsy. Cavernous angiomas, in particular, have a characteristic appearance on MRI scans. This paper will define these "occult" vascular malformations of the brain, their incidence, clinical presentation, natural history and issues related to management. The experience of the Department of Neurosurgery and the Division of Neuro-Radiology at the Victoria General Hospital in Halifax during 1990 will be summarized. Of over 1,200 consecutive cranial MRI scans, 18 cases of cavernous angiomas were encountered. Some of these caused intracerebral haemorrhage and others were seen in patients with complex countered. Some of these caused intracerebral haemorrhage and others were seen in patients with complex partial seizures. A surprising number were multiple and familial in occurrence. These lesions can present in the brain stem or spinal cord thus mimicking multiple sclerosis. The majority of them are asymptomatic and are incidental findings. Venous angiomas are, in fact, hamartomas and rarely lead to symptoms; because they drain normal neural tissue they cannot be sacrificed without risk of significant neurological sequelae. The emerging literature on angiographically occult vascular malformations of the brain will be reviewed (AU)

Epilepsy: disappearing lesions appearing in the United Kingdom

Objective: - Investigation of spontaneously resolving lesions associated with epilepsy. Design:- Observational study during one year. Setting:- One neurology department. Patients:- 4 cases in patients (one of Indian parents, one African, one white English, and one Afro-Caribbean) resident in the United Kingdom, who presented with transient epilepsy. Main outcome measures:- Findings on computed tomography and on screening for infections. Results:- In all four cases a small mass lesion in one cerebral hemisphere was observed on computed tomography, which resolved after 9, 4, 3 and 1.5 months respectively without surgery. Conclusions:- The number of cases seen in one year suggests that the lesions may be more common in the United Kingdom than previously recognised and that research into their cause is warranted. (AU)

Pathological and immunological observations on tropical spastic paraparesis in patients from Jamaica

The neuropathological examination of the spinal cord of 2 Jamaican patients with classical tropical spastic paraparesis disclosed an intense chronic meningomyelitis with demyelination. In the 1 case in which serum and cerebrospnal fluid were available, antibodies to the human T-lymphotropic virus type 1 were found. (AU)

Regional differences during cerebellar corticogenesis in the rhesus monkey - abstract

This study was undertaken to gain more insight into the complex morphology of the mammalian cerebellum. Investigators of earlier days who attempted to elucidate the fundamental organization of the cerebellum were mainly occupied with the gross morphology of its lobes and fissures, and this closed the eyes initially to other principles of organization. Recent anatomical and electrophysiological studies, however, have increasingly raised support for the concept of a fundamental division of the cerebellum into 4 longitudinal zones with their subdivisions, rather than into transverse lobes and lobules. These zones are based on the compartmentilization of certain afferent and efferent fiber systems of the adult cerebellum. Studies of the development to the cerebellum in a few mammals and man, also revealed the existence of a transient zonal pattern. The latter, however, is based on the temporary clustering of Purkinje cell neuroblasts in the cortical anlage. In the rhesus monkey this period lasts from d.48 until d/80. Horizontal and frontal serial sections of each age were available. The first indication of regional differences is noted on d.50. Between d.54 and d.65 the clusters become increasingly clear and it is possible to distinguish them individually. As development progresses, the clusters are gradually transformed into a Purkinje cell monolayer, which is apparent around d.80. It is highly probable that before it fades away, the embryonic zonal pattern acts as the mould for the permanent adult pattern (AU)

Hypertension and the brain

Major brain illnesses attributable to arterial hypertension include: (a) Infarction - Cerebral/Lacunar (b) Encephalopathy (c) Haemorrhage. Arterial hypertension affects the capacity of the crebral arteries to volumetrically regulate CBF and causes structural changes in the arterial wall. The deficits resulting from lacunar infarction can be substanial if important structures are involved. Primary hypertensive brain haemorrhage has been called an "Oh, my head" syndrome, because these words are often among the last conscious utterances of the affected patient. The putamen, internal capsule and thalamus are the most common sites of origin for hypertensive intracerebral haemorrhage and are best distinguished clinically by examination of eye movement. In patients with primary hypertensive intracerebellar haemorrhage, rapid surgical intervention can yield gratifying results. The decline in the incidence of strokes correlates positively with improving detection and more efficient treatment of vascular hypertension. The only adequate treatment of stroke is prevention (AU)

Current concepts of abnormal motor disorder: an experimental model of attentional deficit disorder

An attempt was made to indicate the neuropharmalogical relationship between Parkinson's disease, Huntington's chorea, tardive dyskinesia and Attentional Deficit Disorder. In the case of the latter, an experimental model has been prersented indicating cholinergic dysfunction in the nigro-striatal pathway. Postulates are proposed which will enable us to understand the many factors responsible for these clinical states. (AU)

Avian encephalomalacia in Barbados, West Indies: a description of spontaneous field cases with feed analyses

The clinical, necropsy and histopathological findings in four natural outbreaks of encephalomalcia are reported. Feed analyses implicated low levels of vitamin E as the probable cause of the condition. Treatment with vitamin E has proved to be very effective. The instability of vitamin E in animal feed ingredients during long priods of shipment to the Caribbean may be important in the pathogenesis of the disease. (AU)