N. H. Wadia

Bio: N. H. Wadia is an academic researcher. The author has contributed to research in topics: Myelopathy & Enterovirus. The author has an hindex of 3, co-authored 3 publications receiving 269 citations.

A study of the neurological disorder associated with acute haemorrhagic conjunctivitis due to enterovirus 70.

Abstract: Ninety cases of the neurological manifestations associated with acute haemorrhagic conjunctivitis caused by Enterovirus 70 (EV 70) are reported. The patients were seen during the widespread epidemics in 1971 and 1981. Male adults were predominantly affected by a "polio-like" paralysis of the limbs and/or cranial nerves. Root pains were often complained of early in the disease. In the absence of a necropsy, clinical and neurophysiological examinations helped to localise the lesions. Significant antibody titres against EV 70 were demonstrated in the serum and more relevantly in the CSF. Though other viruses can cause sporadic and epidemic conjunctivitis and similar paralysis independently, the combination of a haemorrhagic conjunctivitis and a neurological disease mostly simulating poliomyelitis is caused by EV 70 alone. It is therefore suggested that this combination be called "Enterovirus 70 disease". Because of its neurovirulence, it is important to identify this virus at the very beginning of an epidemic of conjunctivitis, so as to limit its spread by strict public health measures.

Using saccades as a research tool in the clinical neurosciences

Abstract: Saccades are rapid eye movements that move the line of sight between successive points of fixation; they are among the best understood of movements, possessing dynamic properties that are easily measured. Saccades have become a popular means to study motor control, cognition and memory, and are often used in conjunction with techniques such as functional imaging and transcranial magnetic stimulation. It has been possible to identify several, distinct populations of neurons, from brainstem to cerebral cortex, that contribute to behaviours ranging from reflexive glances to memorized sequences of saccades during learned tasks. This progress has led to the development of schemes for the neurobiology of saccades that imply an equivalence of a region of the brain with specific behaviours (e.g. prefrontal cortex with memory-guided saccades). In fact, multiple neuronal populations contribute to each type of saccadic behaviour, be it 'reflexive' or 'complex'. Furthermore, an important difference exists between cortical areas that encode visual stimuli or desired saccades over a population of neurons as 'place maps', and motoneurons in oculomotor, trochlear and abducens nuclei that dictate eye rotations in terms of their discharge rates. This dichotomy implies that a 'spatial-temporal transformation' of saccadic signals must occur between cerebral cortex and ocular motoneurons, to which the superior colliculus and cerebellum contribute. Consideration of such factors may broaden the value of saccades, which can be used to test a range of hypotheses, and provide a simple scheme for understanding clinical disorders of saccades; some illustrative video clips are available as supplementary material at Brain Online.

Transoral-transpharyngeal approach to the anterior craniocervical junction: Ten-year experience with 72 patients

Abstract: The anterior transoral-transpharyngeal operation to correct ventral irreducible compression of the cervicomedullary junction was utilized in 72 individuals. The patients' ages ranged from 6 to 82 years, and 29 were children. The pathology encountered was primary basilar invagination, rheumatoid irreducible cranial settling, secondary basilar invagination due to migration of odontoid fracture fragments, dystopic os odontoideum, granulation masses, clivus chordoma, osteoblastoma, and chondroma of the atlas. Fifteen patients had associated Chiari malformation with basilar invagination. Fifty-two patients required subsequent atlantoaxial or occipitocervical fusion. Neurological improvement was the rule. There were two deaths within 30 days of surgery: one from myocardial infarction 4 weeks after surgery and one from Gram-negative septicemia of urinary tract origin. There was one pharyngeal wound infection. The ventral transoral approach provides a safe, rapid, and effective means for decompression of the abnormal craniovertebral junction.

Basilar invagination: a study based on 190 surgically treated patients

Abstract: Object. The authors analyzed the cases of 190 patients with basilar invagination that was diagnosed on the basis of criteria laid down in 1939 by Chamberlain to assess the appropriate surgical procedure. Methods. Depending on the association with Chiari malformation, the anomaly of basilar invagination was classified into two groups. Eighty-eight patients who had basilar invagination but no associated Chiari malformation were assigned to Group I; the remainder of the patients, who had both basilar invagination and Chiari malformation, were assigned to Group II. The principal pathological characteristic was observed to be direct brainstem compression due to odontoid process indentation in Group I and a reduction in posterior cranial fossa volume in Group II. Conclusions. Despite the anterior concavity of the brainstem in both groups, transoral surgery was the most suitable procedure for those patients in Group I and decompression of the foramen magnum was found to be appropriate for patients in Group II. A...

Slow saccades in spinocerebellar degeneration.

Abstract: Two patients with spinocerebellar degeneration made abnormally slow horizontal refixations. One patient produced quick phases of nystagmus with identical maximum velocities, suggesting her refixations were abnormal saccades and not voluntary pursuit movements. In response to double target jumps, neither patient showed an obligatory refractory period after each saccade; they responded to every target movement after one reaction time. Their slow refixations were not preprogrammed since they could be modified in flight. To reconcile these observations with normal saccadic behavior, we hypothesized a neural network that made saccades by driving the eyes to an orbital position rather than preprogramming a distance for movement. Computer simulation of this model produced both realistically appearing normal saccades and, when appropriately "lesioned" to simulate a loss of saccadic "burst" neurons in the pontine reticular formation, slow saccades that could be modified in flight.

Craniocervical abnormalities: A comprehensive surgical approach

Abstract: Guidelines are proposed for surgical management of symptomatic abnormalities of the craniocervical junction. Experience with 17 recent cases is described. Gas or metrizamide (Amipaque) myelograms with pluridirectional tomograms revealed the etiology and mechanisms of compression of the cervicomedullary junction, as well as its reducibility. Stabilization was the goal in treatment of reducible lesions. Decompression of the cervicomedullary junction was paramount in irreducible cases. Ventral compression was treated in nine patients by transoral transpalatine resection of the odontoid-clivus complex, and all nine improved. A posterior decompression was carried out when bone impingement was present from the dorsal aspect. Fusion was performed in cases in which stability was not achieved by either procedure.