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Biomedical subjects

N S Chu

Publications and source records attributed to N S Chu.

At least 91 records · Page 5Linked to original sources
PubMed1990

Epileptic seizures in thrombotic stroke.

Epileptic seizures due to thrombotic cerebral infarction were studied in 118 patients. The occurrence of seizures had a bimodal distribution with one peak period within 2 weeks and another peak period from 6 to 12 months after stroke. Four patients had seizures preceding stroke, while 23 patients without a history of previous stroke had "silent infarct" on the CT scan. Fifteen patients (13%) had status epilepticus. Simple partial seizures occurred in 56% of patients, complex partial seizures in 24% and generalized tonic-clonic seizures in 4%. Epilepsy developed in 35% of patients with early seizures and in 90% of patients with late seizures.

Adult↗
PubMed1990

Motor evoked potentials in Wilson's disease: early and late motor responses.

Motor evoked potentials following magnetic stimulation of the motor cortex and the spinal roots were studied in 13 patients with Wilson's disease (WD). The fast-conducting motor pathway function was normal in 9 patients. The cortically-evoked motor responses were absent in patients with cerebral white matter lesion and akinetic rigid syndrome. In addition to the primary or early motor response, late motor response was common in WD and occurred with a latency of 70-90 msec for the upper limb and 90-110 msec for the lower limb. The cause of the late motor response is unknown, but may be an enhanced late response infrequently observed in normal subjects.

Adult↗
PubMed1990

Parkinsonism with neuroacanthocytosis.

Two patients with neuroacanthocytosis are described. One presented with parkinsonism and the other resembled diurnal dystonia of the Segawa type. Both patients responded well to dopaminomimetic therapy. A PET scan with fluorodopa revealed a nigrostriatal deficit in the first patient.

Acanthocytes↗
PubMed1990

Epileptic seizures in elderly people: aetiology and seizure type.

We have studied 342 patients who had their first seizures after the age of 60 years. The causes of seizures were identified in 305 patients (89%) with cerebrovascular disease accounting for 39%, head injury 21%, brain tumours 11%, metabolic disorders 7%, multifactorial aetiology 6%, and CNS infection 4%. The majority of patients (80%) had focal onset seizures that were secondarily generalized in 50%.

Aged↗
PubMed1990

Intrathecal morphine's effect on somatosensory impulses transmission-studied with posterior tibial nerve SSEP.

In order to investigate neurotoxic potential of spinally injected morphine solution, somatosensory evoked potential (SSEP) was utilized to detect the change of electrophysiologic activity of spinal neurons after long term application of intrathecal morphine. Eight patients received intrathecal morphine injection regularly after CHEMO-PORT implantation were studied with posterior tibial nerve SSEP. Patients received SSEP examination just before and right after first episode of morphine injection and were followed up at 30 minutes, 60 minutes, 2 hours, 8 hours, and the 7th day and the third month of regularly injection. The results showed that there were no definite change of latencies and amplitudes of impulses generated by lumbar spinal cord (N22) and cortex (P40). We therefore suggest that electrophysiologic activities of spinal cord and cortex are not affected by chronic intrathecal morphine injection. Possible mechanism and proposed pathway of morphine's action were also discussed.

Evoked Potentials, Somatosensory↗
PubMed1989

Chronic manganese intoxication.

We report six cases of chronic manganese intoxication in workers at a ferromanganese factory in Taiwan. Diagnosis was confirmed by assessing increased manganese concentrations in the blood, scalp, and pubic hair. In addition, increased manganese levels in the environmental air were established. The patients showed a bradykinetic-rigid syndrome indistinguishable from Parkinson's disease that responded to treatment with levodopa.

Adult↗
PubMed1989

Positron emission tomography in manganese intoxication.

We employed 6-fluorodopa to study the integrity of the nigrostriatal dopaminergic projection by positron emission tomography in 4 subjects with clinical features of mild parkinsonism caused by exposure to manganese. The 6-fluorodopa scans were normal. This finding suggests that in early manganism sufficient to cause parkinsonian deficits, damage may occur in pathways postsynaptic to the nigrostriatal system, probably involving striatal or pallidal neurons. Fluorodeoxyglucose scans showed decreased cortical glucose metabolism, the significance of which is discussed.

Adult↗
PubMed1989

Brainstem auditory evoked potentials: correlation between CT midbrain-pontine lesion sites and abolition of wave V or the IV-V complex.

Correlations between CT lesion sites and selective abolition of BAEP wave V or the IV-V complex were made in 16 patients who had discrete midbrain-pontine hemorrhages or tumors. Waves IV and V were consistently abolished by lesions involving the dorsolateral tegmentum of the midbrain-pontine junction area and the upper pons. The abolition of these waves was ipsilateral to the side of the monaural stimulation. Wave V or the IV-V complex was not affected by lesions involving the inferior colliculus, the central pons or the area dorsolateral to the aqueduct. It is concluded that an intact dorsolateral area of the upper pons is a prerequisite for waves IV and V to occur.

Adolescent↗
PubMed1989

Clinical, CT and evoked potential manifestations in Wilson's disease with cerebral white matter involvement.

Four patients with Wilson's disease had CT manifestations of cerebral white matter lesions involving frontal lobes in two patients but extending to other cerebral areas in the remaining two. Two patients with extensive white matter involvement were bed-ridden with generalized flexion rigidity and spasticity, but the other 2 patients led an independent life with minimal extrapyramidal symptoms. Three patients developed tonic focal seizures with or without secondary generalization. Scalp-recorded somatosensory evoked potentials (SEPs) over the affected hemispheres were absent but the spinal SEPs and brain stem auditory evoked potentials were preserved. The evoked potential data support the CT findings that the white matter involvement in Wilson's disease was primarily confined to the cerebral hemispheres.

Adolescent↗
PubMed1989

Status epilepticus in the elderly: etiology, seizure type and outcome.

We have studied status epilepticus among 342 patients who had their first seizures after the age of 60 years. One hundred and two patients (30%) had status epilepticus. Cerebrovascular disease (35%) was the leading cause of status, followed by head trauma (21%), multifactorial etiology (11%), metabolic disorders (10%), brain tumors (8%) and CNS infection (2%). The etiology of status remained undetermined in 13 patients (13%). The majority (80%) had partial status or generalized status with focal onset. Overall mortality was 35%.

Age Factors↗
PubMed1989

Biphasic recovery in n-hexane polyneuropathy. A clinical and electrophysiological study.

We studied the course of recovery in n-hexane polyneuropathy in 4 patients by quantitatively assessing clinical and electrophysiological features. The electrophysiological study included measures of motor conduction of the median, ulnar, tibial and peroneal nerves and sensory conduction of the median, ulnar and sural nerves. After cessation of exposure, there was an initial worsening in muscle strength, sensory deficit and nerve conduction for up to 2-5 months. This deterioration was more severe and prolonged in the lower limbs than in the upper limbs. The period of deterioration was followed by a slow recovery studied for 1 year.

Adolescent↗
PubMed1989

Epileptic seizures in intracerebral haemorrhage.

Among 1402 patients with intracerebral haemorrhage (ICH), seizures occurred in 64 (4.6%) and epilepsy in 35 (2.5%). Seizure was the first manifestation of ICH in 19 patients (30%). Status epilepticus occurred in 11 patients (17%) and it was the initial presentation of ICH in six (9%). The majority had simple partial seizures that were predominantly focal and motor. There were 38 patients with early seizure and 26 patients with late seizure. Ninety per cent of seizures occurred within one year after ICH. Eleven patients (29%) with early seizure developed epilepsy, whereas 24 patients (93%) with late seizure developed recurrent seizures. The incidence of seizure was 32% for lobar haematoma, 2% respectively for putaminal, thalamic and pontine haemorrhages and 1% for cerebellar haemorrhage. Twenty-six (62%) out of 42 patients with lobar haematomas developed epilepsy. Thirteen patients (34%) with early seizure died within three months after the onset of seizures whereas three patients (12%) with late seizure died within the same period. The majority of patients who died had deep-seated haematomas.

Adolescent↗
PubMed1989

Evoked potentials in chronic n-hexane intoxication.

Somatosensory, brainstem auditory and pattern-reversal visual evoked potentials (SEP, BAEP and PVEP) were studied in 5 patients with n-hexane polyneuropathy to determine if the CNS was affected. In SEPs, the median central conduction (N13-to-N20) was normal but the tibial central conduction (N22-to-P40) was delayed. The central conduction time (I-to-V interval) of the BAEP was also prolonged. However, the P100 latency of the PVEP was normal. The present data indicate that the spinal cord and the brainstem are primarily affected in chronic n-hexane intoxication.

Adolescent↗
PubMed1988

Portal-systemic encephalopathy: alterations in somatosensory and brainstem auditory evoked potentials.

Median somatosensory and brainstem auditory evoked potentials (SEP and BAEP) were studied in 40 patients with liver cirrhosis consequent to chronic viral hepatitis. The patients were divided into 4 groups: group 1 with liver cirrhosis only, group 2 with hepatic failure (HF), group 3 with grade 1 or 2 hepatic encephalopathy (HE), and group 4 with grade 3 or 4 HE. The control group consisted of 10 age-matched normal subjects. The major changes occurred in the median cortical SEP late components (peaks after N20 and P25). From group 1 to group 4, there were progressive prolongation and sequential disappearance of the late components. Those changes in the cortical SEPs were reversible. The subcortical somatosensory and brainstem auditory conductions (SEP N13-N20 and BAEP I-V interpeak latencies) were slightly prolonged in all groups of patients. The present data indicate that SEP may be useful in detecting subclinical HE and in monitoring the clinical course of HE. The present data further indicate that chronic portal-systemic shunting in liver cirrhosis may result in a minimal impairment of cerebral function and sensory conduction in the CNS.

Adult↗
PubMed1988

Acute haemorrhagic leucoencephalitis with a prolonged clinical course.

Two cases of pathologically proven acute haemorrhagic leucoencephalitis with clinical features resembling a cerebral tumour are reported. One patient with a left fronto-parieto-temporal mass showed progressive neurological deterioration leading to death in 3 months. Another patient with a right parieto-temporal mass had mild neurological symptoms for one and a half months before complete recovery except for a seizure disorder, following steroid and decompressive therapy. The cases show that acute haemorrhagic leucoencephalitis may not always be rapidly fatal, but may run a prolonged clinical course with recovery.

Adult↗