Motor and somatosensory evoked potentials (MEP and SSEP) were compared after experimental spinal cord injury in Bonnet monkeys (macaca radiata). The MEP and SSEP changes following graded injuries were related to clinical outcome. Eight healthy mature monkeys with a mean weight of 4.2 + 0.9 Kg were chosen for the study. Graded spinal cord injury was caused using 50, 100, 200, 300 gm-cm force by modified Allens' weight drop device. MEP and SSEP recordings were done before injury and at 0, 2, 4 and 6 hours after injury and on the 7th postoperative day. Neurological assessment was done at 24 hours and on the 7th day following injury. 50, 100, 200 gm-cm force caused partial injuries and 300 gm-cm force caused severe spinal cord injury. The predictive value of MEP and SSEP following partial injuries was 80% and 66.67% respectively. Both MEP and SSEP were 100% predictive in severe injury. MEP and SSEP monitoring can therefore be complementary to each other in predicting the neurological outcome in partial injuries to the spinal cord.

The aim of this study was to evaluate the occurrence of micro embolic signals (MES) in patients with a cerebral ischaemia using transcranial doppler monitoring and to find out its diagnostic relevance. We prospectively performed bilateral multigated transcranial doppler monitoring from both middle cerebral arteries in 359 patients with an acute or recent (<4 weeks) cerebral ischaemic event, and in 182 control subjects without a cerebral ischaemic event. MES were analysed according to the standardised protocol. Patients with cerebral ischaemic events had a significantly higher (p<0.00001) rate of MES occurrence (31.8%) than control subjects (5.5%). MES were detected significantly higher in patients with partial or total anterior circulation infarcts (39.1%) than in those with lacunar infarcts (26.0%) or transient ischaemic attacks (27.3%). A correlation of MES and neuroimaging finding was also tried. TCD was found to have a predictive role in microemboli monitoring, predominantly in patients with large vessel territory infarction.

A retrospective analysis of clinicopathological data of 10 patients with clinically unsuspected cerebral metastatic choriocarcinoma was carried out. All patients were young adult females. History of preceding pregnancy/abortion was forthcoming in 5 cases but none had a prior history of abnormal gestation. Features of raised intracranial tension followed by hemiparesis were the commonest presenting symptoms. A clinicoradiologic diagnosis of intracerebral haemorrhagic mass, either primary or secondary to tumour bleed, cortico-venous thrombosis or arteriovenous malformation, was entertained in 8 out of 10 cases. In other two cases, ring enhancing lesions prompted the diagnosis of granulomatous masses. Eight patients were operated upon, of whom two died after short hospital stay, and were autopsied. All had haemorrhagic masses noted at surgery/autopsy. Accurate diagnosis of metastatic choriocarcinoma was established only by histologic examination of these haemorrhages. This report emphasizes the importance of considering metastatic choriocarcinoma as an important differential diagnosis of haemorrhagic intracerebral lesions in women of child bearing age group. Measurement of serum/CSF level of HCG in suspected cases helps to implement early therapy. The diagnostic value of histopathologic examination of surgically resected blood clots in determining aetiology of intracerebral haemorrhagic masses is highlighted.

Non-neoplastic, non-inflammatory cysts of the central nervous system may cause symptoms because of pressure, rupture or secondary inflammation. A total of 145 cases of cysts were reviewed during a study period of 12 years. The clinical details and histological features were noted in all cases. During this period 53 epidermoid cysts, 16 dermoid cysts, 38 colloid cysts, 23 arachnoid cysts, 5 neurenteric cysts, 5 ependymal and glial cysts, 2 Rathke's cleft cysts and 3 unclassified cysts were encountered. The possible histogenesis is also discussed.

Spinal congenital dermal sinus is a rare entity, which supposedly results from the failure of neuroectoderm to separate from the cutaneous ectoderm during the process of neurulation. The present study was undertaken to know the clinical profile of these patients, to study associated anomalies and to assess the results of surgical intervention. We had 23 patients with male : female ratio of 9:16. Only 2 patients were below 2 years of age and most cases (16) were between 2-16 years (mean age =10.2 years). Lumbar region (17 cases) was most frequently involved, followed by lumbosacral and thoracic region in 3 patients each. Only three patients were asymptomatic at the time of presentation. Most of the cases presented with evidence of neural compression or tethered cord syndrome. Only one case presented with spinal abscess. The motor, sensory and autonomic deficits were seen in 20, 11 and 12 patients respectively. Scoliosis and CTEV (congenital talipus equino varus) were the common associated anomalies. MRI revealed associated dysraphic state of spinal cord in 21(>90%) cases. All patients underwent surgical exploration and repair of dysraphic state and excision of the sinus. None of the asymptomatic patients deteriorated. Overall 8 patients improved, 14 got their neurological status stabilized, including 3 asymptomatic cases. Only one patient deteriorated. Postoperative wound infection was seen in 2 cases. As age advances, the chance of developing neurological deficit increases. Associated dysraphic state should be looked for and treated simultaneously, using microsurgical technique, whenever possible. It is better to treat all these cases with aggressive surgical intervention before the neurological deficits appear.

Surgery was performed, through single flap fronto-temporo-orbito-zygomatic approach in 22 patients with skull base lesions. In two of these patients, this approach was combined with a transpetrosal approach. The pathological spectrum consisted of trigeminal neurofibromas (5), spheno-orbital meningiomas (4), carotico-ophthalmic aneurysms (4), basilar top aneurysms (2), cavernous sinus haemangiomas (2), invasive pituitary tumours (2) and one patient each of metastatic adenocarcinoma of the cavernous sinus, transcranial fungal granuloma and tubercular granuloma of the cavernous sinus. Of the 14 tumours, 10 were excised totally/near totally while a subtotal excision was achieved in four. Removal of the anterior clinoid process facilitated the clipping of all the carotico-ophthalmic aneurysms. One basilar top aneurysm was wrapped and the other clipped. One patient of fungal granuloma died of fungal meningitis and one patient of basilar top aneurysm expired as a result of thalamic infarct. The advantages of this approach included excellent exposure of the skull base lesions, making the dissection distance shorter and wider, minimal brain retraction and easy replacement of the single bone flap.

The extended frontobasal approach provides an adequate midline exposure from the anterior cranial fossa to the sphenoclival region. Between November 1991 and August 1999, 13 patients with extensive anterior and anterolateral skull base tumours extending to supra and parasellar regions, cavernous sinus and sphenoclival regions were operated upon using this approach alone (7 patients) or in combination with subtemporal -infratemporal (4 patients) or transfacial (2 patients) approaches. Gross total excision was performed in 8 patients while in 4 patients with malignant tumours and in a patient with extensive skull base fungal granuloma, only partial excision was possible. Basal repair was performed using pedicled pericranium, temporalis muscle or fascia lata. The complications included increase in the cranial nerve paresis, endophthalmitis, facial oedema, CSF leak, frontal haematoma and internal carotid artery injury. This study reviews the operative technique, the indications and the complications of extended frontobasal approach.

Infective intracranial aneurysms are relatively uncommon. They develop due to septic embolisation of the vasa vasorum or lumen of the artery, with resultant focal arteritis and necrosis, leading to aneurysm formation. They are an important cause for intracranial haemorrhage. Six cases of infective aneurysms are described. A focus of infection could be detected in all the patients. Surgery was done in three cases, out of which two patients made significant recovery, while one patient died in the immediate postoperative period. Out of the three cases, treated conservatively with antibiotic therapy, there was total resolution on follow up angiogram in two, while one patient was lost to follow up.

A prospective hospital based study was undertaken to study the effect of methyl prednisolone therapy on sensory and motor functions in tuberculous meningitis (TBM). The patients with TB meningitis seen during 1994-1998 were studied. CT scan, motor evoked potential (MEP) to upper and lower limbs; and median and tibial somatosensory evoked potentials (SEP) were carried out in all the patients. Outcome was defined at the end of 3 months into poor, partial or complete recovery on the basis of Barthel index score. Inj methyl prednisolone (MPS) 500 mg IV was given to 21 patients followed by oral tapering dose of prednisolone over one month in addition to 4 drug anti-tubercular treatment. The control group comprised of 16 patients who received 4 drugs anti-tubercular therapy without any corticosteroid. These groups were comparable with respect to their age, stage of meningitis, Glasgow coma scale score and radiological findings. In MPS group, CMCT was abnormal in 9 and SEPs in 7 patients. In the control group, these were abnormal in 9 and 5 patients respectively. Three months after the therapy the frequency of improvement, deterioration and stationary evoked potential (EP) changes were also noted in both the groups. Diversity of evoked potential changes were also noted. Evoked potential changes were neither significantly different between the groups nor there was any beneficial effect shown in MPS group at 3 months. On the contrary, the control group fared significantly better than the MPS group. Initial MEP and SEP abnormalities were however related to 3 months outcome (p<0.01).

Thrombolytic therapy for acute ischaemic stroke has recently become available in India but its success depends on initiating the treatment in the narrow therapeutic time window. There is commonly a delay of several hours before patients with acute stroke seek medical attention. A prospective study was conducted to assess the factors influencing this delay in admission of acute stroke cases. 110 cases (71 males, 39 females) of acute stroke that arrived within 72 hours at our hospital casualty were recruited. A standardized structured questionnaire was given to patients or their attendants. The median time to casualty arrival was 7.66 hours with 25% cases arriving within 3 hours and 49 % cases within 6 hours. Distance from hospital, contact with a local doctor and low threat perception of symptoms of stroke were independent factors associated with delay in arrival. Living in city, presence of family history and older age were associated with early arrival. There was no correlation with patients' or attendants' sex, educational status, history of previous stroke or transient ischaemic attack, subtype or severity of stroke, time of stroke and availability of transport. Adequate measures need to be taken to improve the public awareness of stroke and the role of local doctors.

Vasculitis causing peripheral neuropathy may be the first sign of HIV infection. We report four such cases in whom the onset of peripheral neuropathy led to the detection of HIV infection. Two patients presented with features of mononeuritis multiplex, while the other two had a lumbosacral polyradiculopathy. A prior history of blood transfusion was forthcoming in one of the patients. Sural nerve biopsies in all the four cases and the muscle biopsy in two, histologically showed evidence of vasculitis. Immunohistochemically, the viral antigen was not demonstrable in any of the biopsies, but on electron microscope, virus-like particles were identifiable in the Schwann cell cytoplasm and the perivascular macrophages in one case. To the best of our knowledge, this is the only report that has documented the virus in the Schwann cells as well as the perivascular macrophages lending credence to the fact that these viruses are neurotropic as well as lymphotropic. Immunoglobulin deposits were not demonstrable in any of the cases, suggesting that direct viral invasion may have a role in the pathogenesis of peripheral nerve vasculitis.

The present study attempts to find a correlation between low serum B-12 levels and dementias. A total of 178 patients of dementia were seen at the cognitive disorder clinic from 1996 to 1998. Serum B-12 levels were studied in 100 patients. 15 patients (39.5%) of Alzheimer's dementia had reduced B-12 levels, while only 5 patients (13.9%) with vascular dementias and 3 patients (11.5%) with other types of dementias had reduced levels. The incidence of low serum B-12 was statistically significant in the Alzheimer's group when compared with the other groups, individually as well as combined together (p<0.05). The aetiopathogenesis and significance of these findings is discussed and the literature is reviewed.

Cortical developmental malformations are an important cause for epilepsy. The epileptic disorder usually begins with sporadic seizures, followed by gradually increasing seizure frequency and culminating in epilepsia partialis continua. We report the de-novo occurrence of focal status epilepticus accompanying hyperpyrexia in two male children, aged 18 months and 4 years. One child had prior neuro-developmental delay, while in the other, developmental milestones were normal. In both instances, there were no seizures prior to the presenting neurological illness. Cerebrospinal fluid examination was normal in both the cases. Magnetic resonance imaging revealed extensive pachygyria in one patient and focal cortical thickening in the other. Therefore, cortical developmental malformation may be suspected as an underlying aetiology in children presenting with de-novo status epilepticus and hyperpyrexia.

A case of medulloblastoma, which disappeared following steroid administration and a single sitting of radiotherapy (8Gy) is presented. At surgical exploration tumour was not found, multiple biopsies were negative. Post operative CT scan too did not show the tumour. Five months later, tumour reappeared in left cerebellar lobe in cystic and solid form. Patient was reoperated and tumour was decompressed. The biopsy showed medulloblastoma. To our knowledge, medulloblastomas are not known to be completely responsive to either of these modalities.

Traumatic intracranial aneurysms constitute less than 1% of all intracranial aneurysms. A case of traumatic distal anterior cerebral artery aneurysm in 18 months old child, treated successfully by microsurgical excision of aneurysm is being reported, along with review of the literature.

Pituitary tuberculomas, mimicking adenomas are very unusual. We describe a rare case of a patient with an exclusively intrasellar mass, and who presented with severe headaches and loss of libido. The lesion was approached trans-sphenoidally and pathological examination revealed a tuberculoma. Complete removal was achieved and the patient followed on anti-tuberculous therapy.

Neurenteric cysts are very rare, particularly in adults. These are congenital intraspinal cysts of endodermal origin. A 67 years old man, presenting with backache and paraesthesiae of one and half years' duration, followed by subacute flaccid paraplegia, developing in a week is described. MRI revealed intramedullary cyst at T7. He underwent emergency thoracic laminectomy and complete excision of the cyst. Histopathology confirmed a neurenteric cyst. In view of their rarity, peculiarity in terms of age, location and presentation, we report this case.

Sinus pericranii is a rare vascular anomaly. A case of sinus pericranii at the nasion with an orbital extension is presented. The drainage was into the superior sagittal sinus. The pathogenesis is discussed and the literature is reviewed.

A 3 year and 6 month old girl with epilepsy associated with dural arteriovenous malformation (DAVM), diagnosed on the MRI, is presented to emphasise the importance of DAVM in the aetiology of childhood epilepsy.

Reversible posterior leukoencephalopathy syndrome (RPLE) is an increasingly recognised disorder, most commonly associated with malignant hypertension, toxaemia of pregnancy or the use of immunosuppressive agents. Two cases of RPLE syndrome occurring in the setting of accelerated hypertension and eclampsia are described. Both patients had seizures, altered sensorium and typical findings on neuroimaging. They had complete clinical and radiological recovery. The clinical course, pathophysiology and neuroimaging features of RPLE syndrome are discussed.

Suprasellar tuberculomas are exceptionally rare and are even rarer in children. A case of suprasellar tuberculoma in a five year old male child who presented with diabetes insipidus, hypothyroidism and visual field defect is described. Deranged CSF parameters, imaging findings of a suprasellar rounded, peripherally enhancing lesion with thickening of the pituitary stalk, led to an accurate diagnosis of tuberculosis. The patient responded well to antituberculous treatment and an unnecessary surgery was avoided.

Photosensitive epilepsy is a type of reflex epilepsy. Five percent of epileptics are photosensitive, i.e. they show photoconvulsive response (PCR) during intermittent photic stimulation. Patients with photogenic or photosensitive epilepsy have seizures with flickering light. They also exhibit heliotaxis. Sodium valproate and ethosuximide are the common drugs used. Even though benzodiazepines are useful, the specific effect of lorazepam is not mentioned. We report 5 cases of photosensitive epilepsy with inadequate response to usual antiepileptic drugs who had complete or near complete remission with lorazepam.

A 46 year old male inadvertently consumed 500 ml of glycerol and presented with altered sensorium, focal neurologic signs and generalised seizures. He was managed conservatively and recovered fully within 48 hours. The case highlights the rare presentations of overdosage and neurologic effects with glycerol, an otherwise safe drug used in neurology.

We report a 30 years lady who developed transverse myelitis following an accidental electric shock and later recovered completely.