Diffusion-weighted MR imaging in neonatal nonketotic hyperglycinemia. (9/159)

To our knowledge, we are the first to report the diffusion-weighted MR imaging findings in a 15-day-old neonate with nonketotic hyperglycinemia. We found bilaterally symmetrical lesions of restricted diffusion in the dorsal brain stem, cerebral peduncles, and posterior limbs of the internal capsule, which were more conspicuous and extensive on diffusion-weighted MR images than on T2-weighted images. These lesions are in the myelinated tracts of the neonate and are compatible with the expected sites of abnormality in vacuolating myelinopathy.  (+info)

Brain MR imaging in neonatal hyperammonemic encephalopathy resulting from proximal urea cycle disorders. (10/159)

We present brain MR images in three patients with neonatal-onset hyperammonemic encephalopathy resulting from urea-cycle disorders (two sisters with deficiency of the carbamyl phosphate synthetase I reaction step and one boy with an ornithine transcarbamylase deficiency). MR imaging revealed almost identical findings of injury to the bilateral lentiform nuclei and the deep sulci of the insular and perirolandic regions; to our knowledge, this pattern has not been previously reported. We hypothesize that these lesions presumably reflect the distribution of brain injury due to hypoperfusion secondary to hyperammonemia and hyperglutaminemia in the neonatal period.  (+info)

Leigh Syndrome with COX deficiency and SURF1 gene mutations: MR imaging findings. (11/159)

Mutations in the nuclear SURF1 gene are specifically associated with cytochrome c oxidase (COX)-deficient Leigh syndrome. MR imaging abnormalities in three children with this condition involved the subthalamic nuclei, medulla, inferior cerebellar peduncles, and substantia nigra in all cases. The dentate nuclei and central tegmental tracts were involved in two cases each (all instances), and the putamina, interpeduncular nucleus, and pallido-cortical-nigro-cortical tracts in one. MR imaging pattern recognition can suggest an underlying COX deficiency and should prompt investigators to search for SURF1 gene mutations.  (+info)

Differential features of metabolic abnormalities between medial and lateral temporal lobe epilepsy: quantitative analysis of (18)F-FDG PET using SPM. (12/159)

Because limited resection could yield an equally good surgical outcome as standard anterior resection in temporal lobe epilepsy (TLE), the differentiation of medial from lateral TLE is important. We tried to find the differential features in metabolic abnormalities between medial and lateral TLE groups using quantitative analysis including statistical parametric mapping (SPM). METHODS: We examined 113 (18)F-FDG PET scans of TLE patients who had surgically and pathologically proven lesions and a good surgical outcome (78 medial TLE, 35 lateral TLE). Each scan was compared with those of 22 healthy control subjects to detect hypometabolic regions using a t test of the SPM method and interhemispheric asymmetry using 2-group, 2-condition analysis on SPM. Group analysis was performed between medial and lateral TLE using mirrored PET images. The sensitivity was defined as the detection rate of hypometabolism in the ipsilateral temporal lobes, and the specificity was defined as the nondetection rate in the contralateral lobes. The extent of the hypometabolism was calculated as the number of significant voxels, and the severity was calculated by the asymmetry index (ASI), in the medial or lateral temporal lobes on Statistical Probabilistic Anatomical Map template images. RESULTS: The hypometabolism in the temporal lobes was detected ipsilateral to the seizure focus in 76% of the TLE patients (76% in medial TLE, 77% in lateral TLE) but on the contralateral temporal lobes in 32% of the patients. After considering interhemispheric temporal asymmetry, the sensitivity was found to be 89%, and the specificity was 91% without differences between the medial and lateral TLE groups. In both medial and the lateral TLE, the hypometabolism was more prominent in the lateral cortical structures than in the medial structures. The hypometabolism in the medial temporal structures was found less frequently in the lateral TLE group, and the extent of the hypometabolism was significantly larger in the medial TLE group. ASIs of the medial temporal structure and superior temporal gyrus of lateral temporal structure were significantly higher in the medial TLE. CONCLUSION: SPM analysis of (18)F-FDG PET in TLE patients could localize accurately the seizure focus and helped in the discrimination of the medial TLE from the lateral TLE. We suggest the lateral TLE, rather than the medial TLE, should be considered when glucose metabolism is relatively preserved in the medial temporal structures.  (+info)

Generalised periodic epileptiform discharges: clinical features, neuroradiological evaluation and prognosis in 37 adult patients. (13/159)

Generalised periodic epileptiform discharges (GPEDs) are very rare patterns and are classified as periodic short-interval diffuse discharges (PSIDDs), periodic long-interval diffuse discharges (PLIDDs) and suppression-burst patterns according to the interval between the discharges. In this study we analysed the demographics, history of the seizures during the current illness, mental status, diagnosis, metabolic abnormalities, neuroimaging studies and prognosis of 37 adult patients who had GPEDs in their EEGs. Ages ranged from 17 to 82 years (mean 45 years). There were 19 males and 18 females. The most common aetiology of GPEDs was metabolic and/or infectious disease which was established in 22 patients (59.5%). Other aetiologies included subacute sclerosing panencephalitis (SSPE) in 11 patients (29.7%) and Creutzfeld-Jakob disease (CJD) in 4 patients (10.8%). We showed that structural lesions were found in most of the patients with GPEDs, but concurrent metabolic abnormalities and/or infectious diseases were also detected. Consciousness was impaired and clinical conditions were poor in various degrees in all of the patients when GPEDs were seen. Relatively little is known regarding the mechanism of GPEDs. When GPEDs are seen in EEG, the patient should carefully be checked for metabolic abnormalities and/or infectious diseases and intracranial lesions. GPEDs may be helpful in the determination of prognosis, showing the poor prognosis especially in cases when suppression-burst pattern is seen.  (+info)

Electrophysiological studies in cerebrotendinous xanthomatosis. (14/159)

Seven patients with cerebrotendinous xanthomatosis (CTX) were studied by electrophysiological techniques. The percentages of abnormalities detected in nerve conduction studies and electroencephalograms were 28.6% (two patients) and 100%, respectively. All patients showed prolonged central conduction times in short latency somatosensory evoked potentials (SSEPs) by tibial nerve stimulation but normal SSEPs by median nerve stimulation. Brain stem auditory evoked potentials and visual evoked potentials were abnormal in three (42.9%) and four patients (57.1%), respectively. These electrophysiological parameters were correlated with the ratio of serum cholestanol to cholesterol concentration. The results of SSEPs suggest that the polyneuropathy in CTX is caused by distal axonopathy affecting longer axons before shorter axons (central-peripheral distal axonopathy).  (+info)

Electron tomography of degenerating neurons in mice with abnormal regulation of iron metabolism. (15/159)

Previous studies have shown that IRP1(+/-) IRP2(-/-) knockout mice develop progressive neurodegenerative symptoms similar to those observed in human movement disorders such as Parkinson's disease. Histological investigations using optical microscopy show that these IRP knockout mice display accumulation of ferritin in axonal tracts in the brain, suggesting a possible role for excess ferritin in mediating axonal degeneration. Direct observation of the 3D distribution of ferritin by electron tomography indicates that ferritin amounts are increased by 3- to 4-fold in selected regions of the brain, and structural damage is observed within the axon as evidenced by the loss of the internal network of filaments, and the invaginations of neighboring oligodendrocyte membranes into the axonal medium. While optical microscopic investigations suggest that there is a large increase in ferritin in the presumptive axonal regions of the IRP knockout mice, electron tomographic studies reveal that most of the excess ferritin is localized to double-walled vesicular compartments which are present in the interior of the axon and appear to represent invaginations of the oligodendrocyte cells into the axon. The amount of ferritin observed in the axonal space of the knockout mice is at least 10-fold less than the amount of ferritin observed in wild-type mouse axons. The surprising conclusion from our analysis, therefore, is that despite the overall increase in ferritin levels in the knockout mouse brain, ferritin is absent from axons of degenerating neurons, suggesting that trafficking is compromised in early stages of this type of neuronal degeneration.  (+info)

A rational approach to dementia. (16/159)

Dementia is a common problem facing all medical practitioners and it frequently results in hospitalization and death. This review provides a framework for dealing with dementia in clinical practice that is based on both traditional concepts and recent advances in the understanding of the problem. Distinguishing at the bedside between dementia and other disorders of intellect is emphasized. The main causes of dementia and their clinical characteristics are reviewed and a rational approach to definitive diagnosis is developed. Simple, effective symptomatic forms of therapy are described.  (+info)