[Paretic syndrome of spinal stenosis]. / Le syndrome parétique du canal lombaire étroit.

We report a case of painless progressive leg amyotrophy without intermittent claudication due to spinal lumbar stenosis. Our attention was drawn to the lumbar region because of the discrepancy between normal leg sensory potentials and altered somatosensory evoked potentials, prompting us to perform a myelography. The rapid though partial, clinical improvement following decompressive surgery suggested that some of the symptoms may have been due to a reversible nerve conduction block.

Cylindrical spinal meningioma. A case report.

A case of cylindrical spinal meningioma is reported. This most unusual morphology suggested a preoperative diagnosis of either lymphoma, metastatic epidural tumor, or meningioma. At operation, the tumor was found to be hard and extremely adherent to the cord, so its anterior part had to be left in place. Transient paraplegia was observed postoperatively, but the patient recovered normal stance and gait within 6 months. Three years after the operation, magnetic resonance imaging demonstrated a very slow progression of the remaining tumor with an estimated increase of 5%. The differential diagnosis of this lesion by magnetic resonance, its clinical postoperative evolution, and the surgical strategy are discussed.

High resolution SPECT with [99mTc]-d,l-HMPAO in normal pressure hydrocephalus before and after shunt operation.

Cranial CT and high resolution measurements of regional cerebral blood flow (rCBF) with brain dedicated single photon emission computer tomography (SPECT) and [99mTc]-d,l-hexamethylpropyleneamine oxime ([99mTc]-d,l-HMPAO) were performed before and after shunt operation in 14 consecutive patients with dementia and normal pressure hydrocephalus (NPH). When compared with a control group of 14 age matched healthy volunteers, the group of NPH patients was characterised by an enlarged subcortical low-flow region, significantly reduced rCBF and enhanced side-to-side asymmetry of rCBF in the central white matter, and enhanced side-to-side asymmetry in the inferior and mid-temporal cortex. Global CBF was normal. Shunt operation reduced the mean area of the ventricles on CT and of the subcortical low-flow region on SPECT. Global CBF was unchanged. All 14 patients had an abnormal pre-shunt rCBF pattern with enlargement of the subcortical low flow region, focal cortical blood flow deficits, or both. Shunt operation improved the clinical status in 11 patients, and the area of the subcortical low flow region correctly classified 3/3 unimproved and 10/11 improved patients. Shunt operation normalised or reduced the area of the subcortical low flow region in nine of 10 patients. It is concluded that SPECT with [99mTc]-d,l-HMPAO is a useful supplement in the diagnosis of NPH versus normal ageing, and that SPECT may help to identify patients not likely to benefit clinically from surgery.

Anterior sacral meningocele and Marfan syndrome: a review.

Anterior sacral meningocele is a not rare entity. Treatment is usually surgical and consists in a transacral posterior approach with patching of the communication between the malformation and the dural sac. But surgery can be difficult and require multiple procedures. We report the first case of a giant anterior sacral meeningocele rapidly cured by a simple endoscopic procedure. We believe that more attention should be used in the diagnosis of such cases as they can be so easily cured. We have reviewed the literature about anterior sacral meningocele and particularly its treatment and its association either with Marfan syndrome or a familial occurrence.

Morphological quantitative analysis of intracranial pressure waves in normal pressure hydrocephalus.

This work presents a prospective morphological and quantitative analysis of 43 intracranial pressure recordings performed on normal pressure hydrocephalic patients. This analysis led us to separate Lundberg's B waves into different subtypes and to refine the definition of the 'Plateau' wave. Two B wave subtypes named Great Symmetrical wave and Intermediate wave appeared correlated with the surgical improvement. In addition, the degree of post-operative improvement was correlated with the frequency of Intermediate wave. An extended quantitative classification of intracranial pressure waves is proposed that can be used alone to determine which patients should undergo a shunting procedure and which one should the most improve.

Cerebral blood flow deficits in hereditary essential myoclonus.

Hereditary essential myoclonus is a disease in which segmental myoclonus is the sole clinical abnormality and whose cause is unknown. It is characterized by an early onset, a benign course, an autosomal dominant pattern of inheritance, the absence of any other neurologic dysfunction, and normal results of auxiliary tests. Cerebral blood flow studies of a father and son with this disease showed a cortical blood flow reduction contralateral to the myoclonus symptoms. We postulate the cause to be a focal unilateral subcortical cerebral lesion, either in the basal ganglia or in the brain stem, with subsequent cortical deafferentation.

Traumatic brain edema induced by ventricular puncture. A study by magnetic resonance imaging.

Magnetic resonance imaging demonstrates after ventricular catheterization a focal brain hypersignal corresponding to a parenchymal edema along the drain track. In the course of our daily clinical activity, this hypersignal extension seemed more pronounced when catheterizing the frontal area than the junctional parieto-temporo-occipital parenchyma (or trigonal area). In order to confirm this impression, we prospectively studied ten consecutive patients with normal pressure hydrocephalus in whom both of these brain regions were successively catheterized first by a frontal puncture for intracranial pressure monitoring and then by a trigonal one for a ventricular shunt. Each patient was evaluated by serial magnetic resonance imaging. The extension of the hypersignal induced by both catheterizations was estimated on a scale of five grades (0 to 4) of hypersignal extension. A statistically significant more important hypersignal extension was demonstrated at the level of frontal area when compared to the trigonal one. We discuss the likely underlying mechanisms of this phenomenon.

99mTc-d,l-HMPAO and SPECT of the brain in normal aging.

Single photon emission computed tomography (SPECT) with 99mTc-d,l-hexamethylpropyleneamine oxime (99mTc-d,l-HMPAO) was used to determine global and regional CBF in 53 healthy subjects aged 21-83 years. For the whole group, global CBF normalized to the cerebellum was 86.4% +/- 8.4 (SD). The contribution of age, sex, and atrophy to variations in global CBF was studied using stepwise multiple regression analysis. There was a significant negative correlation of global CBF with subjective ratings of cortical atrophy, but not with ratings of ventricular size, Evans ratio, sex, or age. In a subgroup of 33 subjects, in whom volumetric measurements of atrophy were performed, cortical atrophy was the only significant determinant for global CBF, accounting for 27% of its variance. Mean global CBF as measured with the 133Xe inhalation technique and SPECT was 54 +/- 9 ml/100 g/min and did not correlate significantly with age. There was a preferential decline of CBF in the frontal cortex with advancing age. The side-to-side asymmetry of several regions of interest increased with age. A method was described for estimation of subcortical CBF, which decreased with advancing cortical atrophy. The relative area of the subcortical low-flow region increased with age. These results are useful in distinguishing the effects of age and simple atrophy from disease effects, when the 99mTc-d,l-HMPAO method is used.

Frontal impairment and hypoperfusion in neuroacanthocytosis.

Cerebral blood flow tomography, by xenon 133 inhalation or HMPAO (99mTc-d, l-hexamethyl-propylene amine oxime) technetium Tc 99m injection, revealed a severe hypoperfusion in both frontal lobes of a 40-year-old woman with confirmed neuroacanthocytosis. This finding occurred in conjunction with neuropsychological deficits consistent with selective frontal lobe dysfunction. This observation is the first documentation of this type of dementia in neuroacanthocytosis.

Cerebral blood flow in progressive aphasia without dementia. Case report, using 133xenon inhalation, technetium 99m hexamethylpropyleneamine oxime and single photon emission computerized tomography.

We report a case of progressive aphasia without clinical signs of intellectual or behavioral impairment, satisfying Mesulam's clinical criteria of primary progressive aphasia, as 4 yrs of extensive psychometric testing and radiological imaging, comprising CT and MRI, failed to detect evidence of relevant involvement outside the left perisylvian regions. Cranial CT was normal but MRI showed multiple bilateral lesions in the deep white matter. Cerebral blood flow (CBF) studies by single photon emission computerized tomography, however, showed an initial frontotemporal focus of hypoperfusion that progressively extended to include most of the ipsilateral hemisphere and the contralateral frontal lobe. This suggests that CBF imaging may yet be the most sensitive technique in revealing subclinical injury in the degenerative brain diseases of focal onset.

Regional cerebral blood flow in patients with affective disorders.

Regional cerebral blood flow at rest was measured in 38 patients with major depressive disorders and 16 controls by SPECT with inhalation of xenon-133. All subjects had been withdrawn from medication. The mean hemispheric cerebral blood flow was not statistically different between the controls and the different subgroups of depressed patients defined either by biological markers or clinical characteristics. However, the predominantly cortical blood flow, measured on the outer cerebral rim of the third tomographic slice, was significantly lower on the left hemisphere in bipolar patients when compared with normals and unipolar patients. The same lateralisation was observed in patients with an endogenous depression according to the Newcastle scale.

Vertebrobasilar insufficiency revealed by xenon-133 inhalation SPECT.

A study of cerebral and cerebellar blood flow reactivity to acetazolamide by xenon-133-inhalation single photon emission computed tomography (133Xe SPECT) was carried out in a patient with bouts of transient basilar ischemia, whose neurological examination, computed tomographic scan, and auditory evoked potentials were normal. Though the patient was symptom-free at the time of the study, 133Xe SPECT demonstrated vertebrobasilar insufficiency by showing an impaired vasodilatory response in both the occipital lobes and the right cerebellar hemisphere. Three weeks later, the patient suffered an extensive stroke in these same areas. We therefore suggest that this method could be of great value in the assessment of vertebrobasilar insufficiency.

Somatosensory conduction in vitamin B12 deficiency.

We tested the hypothesis that the somatosensory central conduction time (CCT) can reveal central nervous system involvement in vitamin B12-deficient patients when this cannot be established on clinical grounds alone. Three patients with pernicious anemia and without clinical signs of upper motor neuron lesion had a striking increase of CCT. This increase was shown to be reversible in 1 patient who improved over 3 years of treatment. Detailed analysis of the CCT showed that the decrease of conduction velocity occurred in the posterior columns, whereas the conduction was normal at the thalamo-cortical level. We conclude that CCT is a useful parameter to localize and quantify central nervous system disease in vitamin B12 deficiency.

Unusual pattern of somatosensory and brain-stem auditory evoked potentials after cardio-respiratory arrest.

Two patients in coma after cardio-pulmonary arrest showed bilateral absence of all brain-stem auditory evoked potentials contrasting with normal brain-stem reflexes and normal somatosensory cortical evoked potentials. In both patients pre-existing dysfunction of peripheral auditory structures could be ruled out. Subsequent neuropathological analysis showed that the anoxic-ischaemic lesions were restricted to Sommer's sector and the Purkinje cells. These unusual data suggest the hypothesis that a severe hypoxic-ischaemic insult may impair cochlear function and interfere with the activation of the intact auditory pathways.