Clinical and experimental neurology最新文献

An electrophysiological assessment has been performed studying somatosensory, visual and auditory pathways in clinically affected and unaffected members from 4 pedigrees with the autosomal form of 'pure' familial spastic paraplegia (n = 32). In some members from 2 families, testing of all 3 sensory pathways showed abnormal results, even in those clinically unaffected. In another family, some had abnormal somatosensory and visual pathways, with no involvement of the auditory pathway. In a further family, the somatosensory and brainstem auditory pathways were abnormal, with sparing of the visual pathway. These findings indicate that the neuronal degeneration in familial spastic paraplegia extends beyond the spinal cord and involves the visual and auditory pathways. The differences between families, and the asymptomatic abnormalities in clinically unaffected members, suggest diversity in the expression of the genetic defect.

Lithium is potentially toxic to many parts of the central and peripheral nervous systems. Clinical lithium neurotoxicity may appear at any time during therapy and probably often goes unrecognised, at least for a time. Acute lithium toxicity has a mortality of 15%, and 10% of survivors suffer permanent neurological sequelae that are largely unpredictable though persons with the longest and most clinically severe intoxication are probably at highest risk. Even rapidly effective treatment with haemodialysis will not always protect against permanent residual neurological deficits. Lithium may also produce neurotoxic syndromes which develop chronically. There is a large variation among patients in relation to what constitutes a toxic serum lithium level. Both acute and chronic toxicity can occur with therapeutic range serum lithium levels. Failure to appreciate this fact may lead to delays in diagnosis and treatment, placing the patient at risk of permanent neurological damage or death. The diagnosis of lithium intoxication is largely clinical though the EEG may help if typical though non-specific EEG changes are present. If available, the red cell:plasma lithium ratio may be a sensitive indicator of intoxication. Prompt and effective treatment is indicated once the diagnosis of lithium intoxication is made. Prevention of intoxication, which requires the active involvement of both the doctor and patient, is crucial.

The diagnosis of median nerve compression neuropathy at the carpal tunnel is usually confirmed by clinical electrophysiology. The classical findings of a significantly slowed median nerve conduction velocity for both sensory and motor fibres, with a prolonged distal motor latency and a reduced amplitude compared to age-related norms are unambiguous, but these criteria are often present only in part. In such cases another quantitative indicator of compression neuropathy would be extremely helpful. The present study aimed to test whether measurement of warm and cold sensory acuity in cases of putative median nerve carpal tunnel compression would aid diagnostic certainty. Warm sensation is mediated by unmyelinated C-afferents, while cold sensation is conveyed by thinly myelinated A delta afferents. Because compression usually blocks larger diameter fibres first, cold perception on the skin of the palm distal to the compression should be more impaired than is warm perception. Standard electrophysiological measurements (median and ulnar motor and sensory nerve conduction velocities) were made, then perceptual thresholds for both warm and cold stimuli were measured on the skin of the wrist above the carpal tunnel and on the palm of the affected hand in 59 subjects. There was a significantly reduced median motor nerve conduction velocity and prolonged distal motor latency compared to normals. Further, although both thermal thresholds at the wrist were normal, those on the palm were elevated, cold being significantly raised (P less than 0.02) compared both to warm and to age-matched controls. Correlation of the nerve conduction velocity findings and thermal sensory acuity did not yield significant covariance of the positive and negative findings. Overall the results suggest that detection of preferentially elevated cold perceptual threshold (ie reduced cold sensory acuity) on the skin of the palm may aid in the diagnosis of putative carpal tunnel compression in patients with minimal or ambiguous electrophysiological data and provide a functional index of recovery after decompression.

To assess the sequential changes seen in cerebral blood flow using Single Photon Emission Computed Tomography with 99mtechnetium-hexamethylpropylene amine oxime (99mTc-HMPAO SPECT) in acute ischaemic stroke, 35 patients were prospectively studied from June 1990- to March 1991. Scans were performed during the acute phase (1-7 days), sub-acute phase (8-21 days) and chronic phase of stroke (greater than 1 month). Nine patients underwent scans in all 3 phases, 15 patients had 2 scans, and 11 patients had one scan. The majority of infarcts were in the middle cerebral territory (15 patients), while 4 infarcts were in the posterior cerebral territory and two in the anterior cerebral territory. There was a total of 4 lacunar infarcts. Image analysis was by visual inspection and by semiquantitation using homologous regions of interest in opposite hemispheres. SPECT in the acute phase identified the final vascular territory affected in 19 of 27 patients. There were 8 patients in whom early SPECT predicted the vascular territory as seen on late CT scan when the early CT scan was normal. Hyperaemia or reperfusion in the involved vascular territory was identified in 10 patients on scans performed during the sub-acute phase. Late SPECT scans showed perfusion defects greater than the infarct size seen on CT scan in the majority of patients. In all cases, the perfusion defect on the late SPECT scan was equal to or larger than the defect seen on the acute or sub-acute scan. Crossed cerebellar diaschisis was identified in 8 patients, and cortical/subcortical diaschisis in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Ataxia telangiectasia may present with few, if any, of its typical extraneurological manifestations, but the combination of an extrapyramidal movement disorder, ocular motor apraxia with head thrusting and cerebellar incoordination is characteristic. In this sporadic case there was no overt immune dysfunction, oculocutaneous telangiectasia were inconspicuous and the neurological presentation was atypical with dystonia predominating over cerebellar incoordination. The uncontrollable and disabling involuntary movements, which have not to our knowledge been described in ataxia telangiectasia before, showed a partial response to moderately large doses of benzhexol, but were refractory to all other medications. Treatment in the future is to be with increasing doses of benzhexol until the dystonia is controlled or larger doses cannot be tolerated.

The clinical features of 26 patients diagnosed as progressive supranuclear palsy are reviewed. The atypical findings were the relatively low frequency of visual complaints (23%) and of significant dementia (20%). As well, the characteristic eye signs, supranuclear ophthalmoplegia of vertical gaze, occurred some years after the onset of the initial symptoms in a small but substantial number (31%), which significantly delayed the diagnosis, in one case by as long as 18 years. The pathological studies on 2 of the clinical cases and an additional 6 cases showed the characteristic pattern of involvement of particular subcortical and brainstem nuclei. In particular, significant degeneration of the pedunculopontine tegmental nucleus was confirmed. Degeneration of the pedunculopontine tegmental nucleus may well play an important role in the motor disability in progressive supranuclear palsy.

Colour duplex flow imaging is a highly accurate form of non-invasive assessment of the extra-cranial carotid circulation. This method is precise in characterising the degree of carotid stenosis, when compared with intra-arterial digital subtraction angiography. The accuracy of colour duplex in defining mild (1-30%), moderate (31-70%) and severe (71-99%) stenosis was 96%, 95% and 98%, respectively. Sensitivities and specificities were greater than 90% in each category, while positive and negative predictive values ranged from 96% to 100%.

Seven cases of superior sagittal sinus thrombosis seen at Royal Prince Alfred Hospital over the 10 year period 1979 to 1989 have been reviewed. Diagnosis was confirmed by angiography, CT scan or autopsy. The average age was 33 years (16 to 47 years). Five of the patients were female and 2 male. On CT scan the 'empty delta' sign, present in 4 cases, was the most specific diagnostic feature. The underlying causes included primary thrombocythaemia, homocystinuria, post-angiographic investigation of an arteriovenous malformation, and oral contraceptives. In 2 cases no cause was found. Headache was the commonest and earliest symptom, being followed in frequency by convulsions and hemiparesis. Hemiparesis was the commonest sign observed, followed by papilloedema, cranial nerve palsies and impaired level of consciousness. Five of the patients developed signs and symptoms of raised intracranial pressure prior to the appearance of focal neurological deficits, mostly likely due to propagation of the thrombosis to cortical veins. There have been no controlled trials of therapy; however it is important to treat raised intracranial pressure rapidly and effectively, and although the role of anticoagulants remains controversial, their early use may be indicated when there is no radiological evidence of haemorrhage.