Clinical and experimental neurology最新文献

Hereditary sensory radicular neuropathy exhibits autosomal dominant inheritance with complete penetrance in males and incomplete penetrance in females. Newer tests of small sensory nerve function were used in screening 8 family members aged between 14 and 66 years. All exhibited some frequent features of the disorder with an onset in the 2nd or 3rd decade, foot ulceration, foot callus, loss of pin prick, thermal and light touch sensation, and some reduction in vibration acuity and proprioception in the lower limbs. The hands were involved in 3 of 8, muscle involvement was present in 5 of 8, but deafness was not detected by audiometry. Nerve conduction velocity, sensory action potentials, latency and amplitude, thermal acuity, vibration acuity and axon reflex flares were measured in all patients. One sural nerve biopsy confirmed the presence of peripheral fibre loss in this predominantly sensory neuropathy. Chemically evoked axon reflex tests were used to evaluate the extent of primary sensory nerve fibre involvement. All patients were tested using a Moor MBF 3-D dual channel laser Doppler velocimeter. Acetylcholine or phenylephrine iontophoretically applied as 16 mC doses evoked absent or tiny axon reflexes in areas of impaired pin prick sensation. By contrast, direct microvascular dilator responses to nitroprusside (smooth muscle dependent) and acetylcholine (endothelium-dependent) were present but somewhat reduced in areas with defective neurogenic inflammation. These results differ significantly from the responses obtained in age-matched healthy controls (P < 0.05). Foot pressure analysis was performed for orthoses in 2 affected members with foot ulceration using the Musgrave Footprint system.(ABSTRACT TRUNCATED AT 250 WORDS)

Facial paraesthesia due to perineural malignant infiltration is a well recognised complication of basal and squamous cell carcinomas of the head and neck. Perineural involvement was originally attributed to involvement of the perineural lymphatics; however subsequent studies have demonstrated conclusively that these lymphatics do not exist and that the invasion occurs along the line of least resistance. Previous studies on perineural spread of carcinomas of the head and neck have emphasised diagnostic biopsy of an involved nerve (e.g. the infraorbital, mental or major branches of the trigeminal nerve), or at times craniectomy with exploration of the gasserian ganglion. We suggest that in many cases the diagnosis can be obtained by biopsy of the anaesthetic skin alone, without recourse to more involved biopsy techniques. The following case report illustrates this point.

We have studied the relationship between the P300 latency and regional cerebral blood flow (rCBF) in 25 nondemented patients who had lacunar infarctions in the territory of the deep perforating branches of the internal carotid artery system. A significant prolongation of the P300 latency with advancing age was observed. There was a negative correlation between the P300 latency and the rCBF. These results indicate that a combination of P300 latency and rCBF measurements might prove more sensitive in detecting mental decline than rCBF studies alone in nondemented patients with lacunar infarctions.

Since 1983 at the Alfred Hospital 4 patients with thrombotic or embolic vertebrobasilar occlusions have been treated with intra-arterial streptokinase (SK) infusions for the effects of persisting brainstem ischaemia despite anticoagulation with heparin. In 3 cases there was immediate and dramatic neurological improvement, in all cases associated with arteriographically demonstrated reperfusion of a blocked vessel. Two of these patients suffered further thromboembolic vertebral or basilar artery occlusions (3 days and 2 years later) but recovered fully without further thrombolytic therapy. The other patient was given intra-arterial SK 12 days after an apparently completed brainstem stroke: the therapy failed to cause reperfusion of a vertebral occlusion or produce any clinical improvement. Complications from the therapy were nausea requiring the termination of the SK infusion in one case, easily controlled bleeding from a recent surgical wound, and a clinically insignificant haemorrhagic transformation of cerebellar infarction in a third. The benefits of thrombolytic therapy in vertebrobasilar ischaemia and the dose of streptokinase required are discussed.

E-2-en-valproate is a major metabolite present in the blood of humans treated with valproate. In animals it is a potent anticonvulsant. We have measured concentrations of valproate and E-2-en-valproate in 102 plasma samples obtained from 75 adult patients (20 taking valproate only; 55 taking valproate and other anticonvulsants) under steady-state conditions. The two groups' mean ages and weights were comparable. The average valproate daily dose was lower (p < 0.002) in the monotherapy group (1152 +/- S.D. 661 mg/d) than in the polypharmacy group (1902 +/- S.D. 874 mg/d). Despite this, the mean plasma levels of valproate and E-2-en-valproate were significantly higher (p < 0.05, p < 0.0001, respectively) in the monotherapy group (60.0 +/- S.D. 22.6 micrograms/ml; 3.00 +/- S.D. 1.40 micrograms/ml, respectively) than in the polypharmacy group (49.5 +/- S.D. 24.8 micrograms/ml; 1.73 +/- S.D. 0.95 microgram/ml). While the mean plasma valproate level was 17.5% lower in the polypharmacy group, the mean plasma E-2-en-valproate level was 42% lower. The co-administration of other anticonvulsants significantly reduced the concentration of valproate and, more so, of E-2-en-valproate in plasma.

Disturbances of neurovascular function in the extremities may occur in patients with diabetes mellitus, exposure to toxic substances and chronic exposure to vibrating hand tools, as well as in Raynaud's phenomena. In these conditions symptoms of paraesthesia, finger numbness and blanching occur, so nerve conduction studies, vibration and temperature threshold measurements and neurovascular function tests are used for objective assessment of neurological dysfunction. The aim of the present study was to examine some factors which may confound quantitative neuro-vascular function measurements if used to assess neuropathy in diabetics. All subjects were consenting volunteers without exposure to known neurotoxic chemicals. The 5 groups were (a) healthy non-diabetic subjects not exposed to vibration (n = 10, mean age 52.3 yrs) (b) 2 insulin dependent and 8 non-insulin dependent diabetic subjects with a mean of 6 years treatment (n = 10, mean age 55.7 yrs) (c) maintenance employees exposed to high frequency pneumatic hand tools (n = 10, mean age 52.2 yrs) (d) subjects who were not diabetic or exposed to vibrating tools, but were being treated with the ACE-inhibitor enalapril 20 mg daily for hypertension (n = 5, mean age 54 yrs) (e) subjects who had smoked more than 10 cigarettes daily for at least 15 yrs (n = 10, mean age 51 yrs). Neurovascular tests included axon reflex responses measured by laser Doppler velocimeter evoked on the dorsum of the finger by iontophoresis of acetylcholine 16 mC in a circumferential chamber: cutaneous microvascular dilator responses to endothelial stimulation by iontophoretic application of the muscarinic agonist pilocarpine 16 mC and to direct nitrodilator sodium nitroprusside 16 mC. The skin temperature of the digits was held between 33 degrees and 34 degrees C during testing and dilator responses were measured as flux change by on-line computer analysis using 'Perisoft'. There was a significant reduction (P < 0.05) in the neurovascular responses of both diabetics and vibration--exposed subjects to acetylcholine and, in the case of vibration-exposed subjects, to pilocarpine, but nitroprusside responses were not significantly different. Our findings of reductions in neurovascular responses in diabetics and in subjects exposed to higher frequency vibration is consistent with recent epidemiological findings. Furthermore, subjects treated with an ACE-inhibitor (enalapril) showed significant reduction in acetylcholine-evoked axon reflex responses, while the test group of smokers showed a significant reduction in their dilator response to pilocarpine.(ABSTRACT TRUNCATED AT 400 WORDS)

A double-blind, placebo controlled cross over study assessed the efficacy of lamotrigine as adjunct therapy for patients with refractory partial seizures. In addition to the main study, a neuropsychological component evaluated three main areas of cognitive function. These included: i) Concentration and attention; ii) General Cerebral Efficiency, and iii) Mnestic functions--immediate, short term and new learning ability. Ten subjects (4 males, 6 females, age range 22 to 53, mean age 31.3 years) were involved in the study, each assessed 3 times--baseline, end of phase I and end of phase II. Whilst statistical analysis proved impracticable due to differing scores across cells, between the results of lamotrigine and placebo, clinically, there appeared to be a marginal reduction in General Cerebral Efficiency during the lamotrigine phase. In the light of these tests, the conclusion is advanced that lamotrigine does not specifically impair cognitive function, and that it does not impair mnestic function. An alternate hypothesis of interaction effects is posited for the slight reduction in speed of information processing.

The study describes 51 patients, aged 10 to 57 years, who underwent spinal surgery (47) or interventional angiography (4). Multi-channel somatosensory evoked potential (SEP) monitoring was used to measure the functional integrity of the spinal cord. Alternating unilateral tibial SEPs permitted the detection of lateralised and milder abnormality. A combination of recording sites enhanced the certainty of detecting spinal cord dysfunction. Monitoring the ascending peripheral nerve volley below the operative site ensured adequate stimulation. Above the level of surgery, recordings outside the operative field were the simplest to make and did not require the direct assistance of the surgeon. Rapid and reliable recording of spinal cord and subcortical responses was possible in all surgical cases. Even though cortical SEPs could not be relied on as the sole monitor, their reproducibility was improved with the use of different electrode derivations. It is concluded that non-invasive methods of spinal SEP monitoring are a safe, reliable and easily performed alternative to more invasive methods.

The purpose of the study was to determine whether quantitative or discriminant analysis of the electroencephalograph (EEG) would vary significantly when the same EEG was analysed by 3 different operators. EEGs on 10 healthy volunteers were recorded on the Cadwell Spectrum AT 386, using the Electrocap (10-20 system). The EEGs were analysed independently, with each operator selecting the first 48 artifact-free epochs. The results were analysed using the non-parametric Friedman two-way analysis of variance (ANOVA) for the discrimination analysis and a one-way ANOVA for the monopolar and bipolar Absolute Power raw measures. Statistical analysis of the discriminant data showed no significant differences between operators, with 7 of 10 studies yielding the same results. The remaining 3 studies were classified either as borderline or normal when analysed by different operators. Although a series of "t" tests comparing 2 operators showed most variability occurring in Absolute Power as compared with Relative Power, Power Asymmetry and Coherence, ANOVA of the raw mono- and bipolar Absolute Power measures showed no significant differences between the operators at the P = 0.05 level. Thus the differences between the operators were non-significant when comparing quantitative EEG analyses with respect to both the raw measures and the discriminant analyses.

From April 1990 to September 1990, 170 magnetic resonance imaging (MRI) examinations of the brain were made with the Siemens 1.5 Tesla machine (the "Magnetom") in the Hong Kong Baptist Hospital. The indications for the investigation on the referral forms and the results were analysed. The MRI was particularly useful in making the diagnosis in 2 cases of multiple sclerosis, one case of an Arnold Chiari malformation, 6 cases of cerebro-vascular accidents, and 2 cases of encephalitis. MRI has replaced computerised tomography as the study of choice for the majority of central nervous system disorders.