More than half of HIV - infected persons develop symptomatic neurological disease. The nervous system is extensively involved with no part of the neuraxis being immune from the virus. Beisdes the brain and spinal cord, the peripheral nerves and muscles may be affected. Neurological complications typically occur with advanced disease and profound immunosuppression, hence a knowledge of the CD4 lymphocyte count is of paramount importance. Since many of the conditions are amenable to treatment, a proper diagnosis and therapy may decrease morbidity in the already curtailed life span of the patient. Some opportunistic neurological infection is a result of latent/persistent infection requiring lifelong secondary prophylaxis e.g. toxoplasma encephalitis and cryptococcal meningitis. Neuroaids does not follow the law of parsimony i.e. a single entity may not be responsible for the entire constellation of signs and symptoms. HIV infection is the commonest cause of dementia in people under the age 50 in thedeveloped world. Cryptococcosis is the commonest infection affecting the nervous system in HIV positive patients. Tuberculosis has seen a resurgence following the out break of AIDS. CNS lymphoma is the commonest cause of raised ICP followed by tuberculoma, toxoplasmosis and brain abscess. Most patients with paraparesis have a typical HIV associated vacuolar myelopathy. A distal predominantly sensory neuropathy is the initial feature of insult to peripheral nerves. Muscle involvement may be due to polymyositis and HIV associated wasting syndrome but may also be aggravated by drugs (e.g. zidoudine).

Selection of the operative route for cavernous sinus related lesions, the extent of the exposure necessary, the need for intra-operative control of the carotid artery and feasibility of radical resection depend on the nature of the tumour. The importance of the arterial relationship in preoperative evaluation of the histology of the lesion and the impact on decision regarding the surgical strategy is discussed in the present report. An anatomical, radiological and clinical analysis of some of the more common lesions involving the cavernous sinus is presented.

We report our preliminary observations on the role of Gabapentin as an add - on therapy in 16 patients with partial or secondary generalised seizures who were resistant to conventional antiepileptic drugs. There was a reduction in the seizure frequency by more than 50 in 11 (69), less than 50 in 3 (18.75), and increase in 1 (6.25). Adverse effects were noted in 9 (56.25 ) of them. The giddiness and sleepiness was seen in 5 (31.25 ); in one it was so severe that he withdrew from the study. Ataxic gait was observed in 1 (6.25). Reduction in the haemoglobin by 2 gms. occurred in 2 (12.5) and asymptomatic eosinophilia in 1 (6.25). As an add - on drug, the efficacy of Gabapentin was good. Regular haematological monitoring is necessary while the patients are on the drug. Further studies involving large number of patients in our country is necessary.

This multicentre, randomized, double-blind, cross over, placebo controlled study evaluated the efficacy and tolerability of oral Sumatriptan (100 mg) in 100 migraineurs. 59 patients completed the study. The results indicate that by 4 hours post-dose62 of patients treated with Sumatriptan achieved relief of headache, compared with 10 of patients treated with placebo. The results show that oral Sumatriptan is an effective drug for treatment of acute migraine in Indian patients, though smaller dosage may be more beneficial.

Intra-cranial pressure (ICP) monitoring was carried out in 51 patients with head injury, admitted to the intensive care unit of All India Institute of Medical Sciences for a minimum of 24 hours. 74 patients with mass lesion and 33 patients without mass lesion had raised ICP (<15 mm of Hg). CT scan was not always reflective of ICP status. ICP monitoring helped in avoiding unnecessary mannitol therapy in 8 out of 12 patients without mass lesion. In this group presence or absence of raised ICP did not affect the outcome. Among 21 patients with mass lesions initially managed conservatively, 3 were operated upon on the basis of raised ICP alone. Four patients with good Glasgow Coma Sclae (GCS) (11-14), who had raised ICP were operated after clinical deterioration. However, in these patients raised ICP preceded clinical deterioration by 8-12 hours. In electively ventilated patients, raised ICP guided early repeat scan and early detection of postoperative haematomas. Patients with mass lesionand increasing ICP had poor outcome, overall mortality being 41. Among them 48 died due to raised ICP. Damped tracings or blockage of device were the most common complication of ICP monitoring. This complication was recorded in 25 of cases in whom Richmond screw was used and 12 of cases in whom intra-cavitary catheter was used. Six percent cases developed meningitis.

Smears, imprints and frozen sections have been recognised as useful adjuncts to diagnosis by the traditional paraffin section in neurosurgical biopsies. In this study, 251 intracranial space occupying lesions were studied by smears and paraffin sections to determine the causes of error and the possible means to avoid them. There were 63 computed tomography guided stereotactic microbiopsies and 188 open biopsies. The overall diagnostic accuracy was 88. In 6.8 of cases the tumour type was diagnosedcorrectly, but the grade was altered subsequent to examining the paraffin sections owing probably to sampling errors. Only 5.2 of cases had an entirely incorrect diagnosis.

In amyotrophic lateral sclerosis (ALS), both anterior horn cell and corticospinal tracts are affected. H reflex studies were performed in 15 patients to study motor neuron excitability and to correlate the changes with the clinical signs. Soleus H reflex was unrecordable in two patients. In the remaining patients, there was lack of vibratory inhibition and reciprocal inhibition which was consistent with pronounced presynaptic and supraspinal influences respectively. High HM ratio was consistent with increased motor neuron excitability. Significant reduction of maximum M response in our patients was consistent with fall out of anterior horn cells. HM ratio, vibratory inhibition and reciprocal inhibition were not related with power, spasticity, clonus or extensor plantar response, which could be due to asymmetric focal neuronopathy.

Dermatomal somatosensory evoked potentials (DSSEP) from C5-T1 dermatomes were recorded in 20 normal healthy adult volunteers as controls and 61 patients with neck pain. The patients were divided into three groups. Group I : symptomatic patients withclinical signs of C5-T1 radiculopathy and radiological evidence of cervical spondylosis (21 patients). Group II : symptomatic patients without clinical signs of radiculopathy but with radiological evidence of cervical spondylosis (20 patients). Group III: patients with persistent neck pain without any clinical radiculopathy or radiological evidence of cervical spondylosis (20 patients). A complete neurological examination and nerve conduction study of median and ulnar nerves were done to rule out peripheral neuropathy. Normative data was established for DSSEP from C5-T1 dermatomes using the control group and the values obtained were comparable with western normative data. In the group I, DSSEP was abnormal in all the cases. It was possible to preciselylocate the involvement of C5 root in 75 , C6 root in 88.88, C7 root in 92.30 , C8 root in 76.92, and T1 root in 100. The DSSEP was abnormal in 11 patients in Group II, but was normal in all the patients of Gruoup III. DSSEP of C5-T1 dermatomes correlated well with the clinical findings in Group I patients. It was possible to detect subclinical radioculopathy in a significant number of patients in Group II. DSSEP is a simple non invasive method for evaluation of cervical radiculopathy.

Clinicopathologial features of six cases of rhinocerebral zygomycosis are described. The diagnosis was based on the demonstration of broad, non-septate hyphae in tissue sections. Four patients had rhinocerebral/rhinoorbitocerebral zygomycosis and one had isolated cerebral zygomycosis. Intense polymorphonuclear response was the pathological feature in 4 patients. Three cases had angioinvasion resulting in haemorrhage, infarction and necrosis.

Twenty seven children with intractable seizures in the age group of 5 months - 14 years were treated with vigabatrin (VGB) and Lamotrigene (LTG) as an add-on therapy. Fourteen children (6M:8F) were given VGB and thirteen children (9M:4F) received LTG. The drug selection was made according to the type of seizures and associated neurological abnormalities. Attempt was made to exclude children with progressive neurologic disorders or severe systemic disease. EEG, CT scan head and relevant metabolic work up was done in all. VGB was found to be most effective in seizures associated with tuberous sclerosis. It was always useful in infantile spasm (IS) and tonic clonic (TC) seizures. LTG was effective in complex partial seizure (CPS) and TC seizures withmyoclonus.

Intramedullary spinal cord metastatic tumours, generally considered to be rare, are increasingly being diagnosed due to aggressive management of the primary malignancy, better imaging facilities and attempts at total excision of these lesions. Sincethese lesions were diagnosed late in the course of the disease patients were earlier given only palliative treatment. Presently, with more intensive treatment protocols the immediate outcome appears to be better.The present report is about two patients in whom the spinal cord lesion was the primary manifestation of an underlying malignancy. Total excision of the lesion was done in both the patients. Post operatively, one patient had marked improvement in the neurological status. He underwent radiation and chemotherapy and survived for seven months. He later succumbed to multiple secondaries involving the brain. The other patient did not improve in her neurological function in the immediate post-operative period and was lost to follow up.

Davidenkow's syndrome is being reported in three members of a family. The affected subjects had weakness and wasting of the deltoids and the distal muscles of the lower limbs. The onset of the disorder was in the middle of the second decade and the affected subjects retained the capability of independent mobility till the fifth decade. Neuroelectromyographic studies revealed the presence of a demyelinating neuropathy. Sural nerve histology was characterised by loss of myelinated fibres and segmental demyelination.

Intracranial plasma cell granulomas are a rare group of idiopathic inflammatory pseudotumours often mistaken for lymphoreticular malignancies and myeloproliferative disorders. The clinial and pathological findings in respect of four cases of intracranial plasma cell granuloma clinically diagnosed as meningioma and glioma are presented in this report. The range of microscopic features seen included a mixed cell population with predominance of plasma cells, absence of cellular atypia and mitosis, multinucleate giant cells, perivascular cuffing by inflammatory cells and emperipolesis. The major considerations in differential diagnosis of this lesion are discussed.

A 23 year non-diabetic female presented with history of episodic alteration of sensorium, cognitive decline and right hemiparesis. Fasting blood glucose was found to be low on multiple occasions along with raised insulin levels. Abdominal CT scan and coeliac axis angiogram were normal. The diagnosis of insulinoma was confirmed on removal of the tumour on exploratory laprotomy. The patient was left with residual mild dementia and hemiparesis.

A case of multiple spinal cord tuberculomas has been presented because of its rarity and misleading picture on MR imaging. The MRI suggested intradural extramedullary spinal tumours, possibly neurofibromata, because of associated cafe-au-lait spot. Various tubercular processes involving the spinal cord and meninges are discussed in the light of the present case.

50 year old man presented with right sciatica syndrome of 10 months duration. Clinically and radiologically he seemed to have prolapse of intervertebral disc at L5 - S1. At surgery a well demarcated greyish yellow mas sticking to S1 root and adjacemt dura was found. Histology confirmed it to be tuberculoma. Patient was put on anti-tubercular chemotherapy and made good recovery.

A patient of acute disseminated encephalomyelitis (ADEM) with a rare clinical presentation is described. The temporal profile of the disease suggested parainfectious central demyelination. The magnetic resonance imaging (MRI) also showed large demyelinating lesions scattered bilaterally in the cerebral white matter, thalami and brain stem. However, clinically he had only right ataxic hemiparesis and dysphasia without any impairment of cognition or consciousness.

Stroke is a leading cause of morbidity and mortality. A significant proportion of stroke victims in India are below the age of 40 years and may have specific risk factors. 101 patients (42 less than 40 years of age) of ischaemic stroke were studiedat NIMHANS to estimate the relative risk of various contributing factors. Hypercholesterolaemia, hyperglycaemia and hypertension were more common in elderly group, while smoking, alcohol and tobacco abuse were more prevalent in younger age group (relative risk 1.2, 1.9 and 1.5 respectively). A better understanding of these risk factors may play a key role in the prevention of stroke in young.

This study reports long-term (over 6 years) effect of controlled-release carbidopa/levodopa (CRCL, Sinemet-CR) in levodopa-naive Parkinson's disease patients. Parkinsonian features were evaluated utilizing the Northwestern University Disability Scale (NUDS) and modified New York University Parkinson's Disease Rating Scale (NYUPDRS). The NUDS scores showed significant variation over time by 2-way ANOVA (P < 0.0001). Following treatment, compared to baseline scores, the NYUPDRS scores showed significant improvement in rigidity, tremor, bradykinesia, while the postural stability scores worsened and gait scores, after initial improvement, returned to baseline level. At the end of the study period 5 patients were alive, 1 became disabled due to myocardial infarction and 3 were holding on to full time occupations. Three patients developed medication related dyskinesia, 1 developed myoclonus and 1 developed a combination of dyskinesia, motor fluctuations and early morning dystonia. Due to small number of patients, while a definite conclusion cannot be drawn, it appears that the incidence of motor fluctuation may be much less prevalent than dyskinesia in patients with Parkinson's disease treated with CRCL.

Results of corpus callosotomy on ten patients with medically intractable epilepsy, done between 1991 and 1996 are reported. Mean age of the patients was 20.5 years and mean duration of seizures 9.5 years. They underwent neurological assessment, detailed EEG studies and neuropsychological evaluation to rule out a resectable seizure focus. Seven patients underwent anterior callosotomy and three, a two staged total callosotomy. Acute disconnection syndrome was observed in about 50 cases which resolved completely in 1-3 weeks. The outcome was excellent in three, good in three, moderate in three and poor in one after a mean follow up of 21 months. Best response was seen in generalized tonic clonic, absence, atonic and tonic seizures. Most patientshad definite improvement in the quality of life after surgery. Age of patient, age at onset of seizures, duration of seizures and degree of mental retardation had no correlation with the outcome. Total callosotomy was found to have much better outcome compared to partial section. We conclude that callosotomy has a definite place in the management of medically intractable epilepsy especially for some seizure types.