Interest of dual-task-related gait changes in idiopathic normal pressure hydrocephalus.

BACKGROUND: Gait disorders in patients with idiopathic normal pressure hydrocephalus (iNPH) share similar characteristics found in pathologies presenting with higher-level gait disorders that have been specifically associated with gait changes during walking while simultaneously performing an attention-demanding task (i.e. dual tasking). The current study assessed the effect of cerebrospinal fluid (CSF) tapping on quantitative gait modification during single and dual tasking in patients with a suspicion of iNPH. METHODS: Of 53 patients suspected of iNPH, 18 have been included in this study. Gait analysis during single- and dual-task condition (walking and backward counting) before and after tapping of 40 ml CSF has been performed. RESULTS: Gait speed (P < 0.01) and stride length (P < 0.05) were significantly improved during dual-task conditions after CSF tapping compared to the gait performance before spinal tapping, without such improvement for gait parameters during single-tasking. CONCLUSION: Dual-tasking condition better reveals gait improvement after CSF tapping than single-tasking in patients suspected of iNPH.

Late adult onset of Langerhans cell histiocytosis mimicking glioblastoma multiforme.

Langerhans cell histiocytosis (LCH) with multiple organ involvement is a rare disorder in adults. Extrapituitary involvement of the central nervous system (CNS) is uncommon. We report the unusual case of a 55-year-old woman presenting with a left-sided hemiataxia-hemiparesis, left hemisensory loss and short-lasting episodes of an alien left hand due to lesions of the internal capsule and the right thalamus, extending into the mesencephalon associated with extensive surrounding edema, without pituitary involvement. The neuroradiological image suggested glioblastoma multiforme. Brain biopsy revealed inflammatory tissue and "pseudotumoral" multiple sclerosis was suspected. Biopsy of concomitant lung and bone lesions disclosed Langerhans cell histiocytosis. The treatment with pulsed steroids in association with mycophenolate mofetil led to a sustained, clinical neurological remission.

Psychiatric comorbidity in patients evaluated for chronic epilepsy: a differential role of the right hemisphere?

INTRODUCTION: Psychiatric disorders are known to occur frequently in chronic epilepsy. The aim of this study is to investigate the prevalence of psychiatric comorbidity and its relationship to regional cerebral dysfunction in patients admitted to a tertiary epilepsy center for epilepsy surgery. METHODS: 217 patients were investigated. A presurgical workup was performed and allowed precise localization of the epileptogenic focus in 156 patients. Sixty-one patients had multifocal or generalized discharges. After 1-3 psychiatric interviews, a psychiatric diagnosis was made (DSM-IV classification). RESULTS: Psychiatric comorbidity was found in 85 patients (39%), more often in those with right or bilateral hemispheric dysfunction (74%, p = 0.04) with no difference between temporal or extratemporal foci location frequency. Additionally, patients with psychiatric disorders were less likely to undergo epilepsy surgery compared to 'epilepsy-only' patients (p = 0.003), despite similar good outcome in patients with and without psychiatric comorbidity. CONCLUSIONS: Right-sided or bilateral foci seem to represent a risk factor for psychiatric comorbidity in epilepsy, although we did not find any particular association between a psychiatric syndrome and focus localization. Recognition and treatment of psychiatric comorbidity is of major importance since its presence may interfere with patient's decision making for epilepsy surgery treatment.

From amaurosis fugax to asymptomatic bithalamic infarct.

Bilateral paramedian thalamic infarctions are usually associated with impaired consciousness, oculomotor disturbances and neuropsychological changes. A 44-year-old healthy woman presented with amaurosis fugax of the right eye immediately after a Valsalva maneuver. Neurological examination, in particular visual acuity, vigilance and ocular movements, was normal. Blood pressure, ECG and angio-CT of the neck and head vessels were normal, but MRI/DWI and T2 sequences showed recent bi-thalamic ischemic lesions in the paramedian territories. Doppler sonography and transesophageal echocardiography showed a large right-to-left shunt due to an atrial communication, with septum aneurysm. Twenty-four-hours cardiac monitoring was normal but prior to an eventual closure of the cardiac defect she underwent an ambulatory 7-day ECG monitoring which revealed several paroxystic short lasting passages into atrial fibrillation, unnoticed by the patient. The interest in this case is threefold: (1) bilateral paramedian thalamic infarction which usually presents with a devastating clinical picture may occur clinically silent; (2) monocular amaurosis fugax which is usually associated with ipsilateral carotid disease may be the consequence of cardiac embolism, and (3) atrial fibrillation is never completely ruled out, here it was caught only in a 7-days ambulatory R-test, and consequently prevented closure of a possibly asymptomatic patent foramen ovale.

Corneal nerves alterations in various types of systemic polyneuropathy, identified by in vivo confocal microscopy.

BACKGROUND: In vivo confocal microscopy (IVCM) is a newly developed application to assess corneal nerve morphology. The purpose of the study is to evaluate the role of IVCM in the assessment of various types of polyneuropathy, and to define alterations of corneal nerves in such conditions. PATIENTS AND METHODS: Eighteen patients with various types of polyneuropathy were characterized by clinical neurological and ophthalmic examinations, as well as by electroneuromyography (ENMG). Full thickness IVCM of corneal nerves was carried out on all patients and 15 age-matched eyes using Heidelberg Retina Tomograph II (HRT II). The subbasal nerve plexus were statistically analysed regarding long nerve fiber density, nerve branch density, nerve thickness, nerve bead number and nerve tortuosity. RESULTS: In subbasal nerve plexus, the following three parameters were significantly reduced in patients with polyneuropathy compared to controls: long nerve fibre density (p < 0.01), nerve branch density (p < 0.001), and nerve bead number (p = 0.001). In addition, the average grade of nerve tortuosity was 2.87 +/- 0.97 in the polyneuropathic group and 1.17 +/- 0.68 in the control group (p < 0.0001). CONCLUSIONS: IVCM allows a non-invasive, in vivo study of corneal nerves with high resolution. It therefore appears invaluable in clinical investigations. IVCM appears to be valuable in a large variety of polyneuropathic conditions.

"Gourmand syndrome" in a child with pharmacoresistant epilepsy.

We report the case of a 10-year-old boy with pharmacoresistant epilepsy, symptomatic of a right temporoparietal hemorrhagic lesion, who displayed an eating passion as described for the gourmand syndrome (GS) in adults and discuss the role of epilepsy in GS. This patient presented with a significant change in his eating habits (abnormal preoccupation with the preparation and eating of fine-quality food) concordant with the onset of his seizure disorder, without any previous history of eating disorders or psychiatric illness. This observation corroborates the important role of the right cerebral hemisphere in disturbed eating habits, including the relatively benign GS, and, possibly rarely, in less benign eating disorders such as anorexia and obesity.

The selective amobarbital test in the anterior choroidal artery: perfusion pattern assessed by intraarterial SPECT and prediction of postoperative verbal memory.

To screen for patients at risk for memory decline after temporal lobe epilepsy (TLE) surgery, selective amobarbital procedures, such as injection into the anterior choroidal artery (ACA-IAT), are sometimes used. We investigated the extent of the territory affected during ACA-IAT and its predictive value with respect to postoperative memory. Seventeen patients with TLE underwent ACA-IAT. In 9 of 17 patients, intraarterial SPECT co-registrated to MRI allowed delineation of amobarbital-perfused structures. Another subgroup of 9 of 17 patients underwent anterior temporal lobectomy. Verbal memory was tested pre- and postoperatively and during ACA-IAT. Major variations in the ACA-IAT perfusion pattern occurred and were not correlated with the verbal memory scores during ACA-IAT. Postoperatively, no patient experienced a severe verbal memory decline, but individual postoperative performance was not correlated with results during ACA-IAT. Our study suggests that ACA-IAT can be used to screen for severe postoperative amnesia in inconclusive cases, but cannot predict individual outcome, even when the perfusion pattern is taken into account.

Distinct mechanisms of form-from-motion perception in human extrastriate cortex.

The exquisite sensitivity of the human visual system to form-from-motion (FfM) cues is well documented. However, identifying the neural correlates of this sensitivity has proven difficult, particularly determining the respective contributions of different motion areas in extrastriate visual cortex. Here we measured visual FfM perception and more elementary visual motion (VM) perception in a group of 32 patients suffering from acute posterior brain damage, and performed MRI-based lesion analysis. Our results suggest that severe FfM perception deficits without an associated deficit of VM perception are due to damage to ventral occipito-temporal cortex (VOT), whereas associated deficits of FfM and VM perception are due to damage either in proximity to area MT+/V5 or an area including lateral occipital complex (LOC) and VOT. These data suggest the existence of at least three functionally and anatomically distinct regions in human visual cortex that process FfM signals.

Favourable outcome of progressive multifocal leucoencephalopathy in two patients with dermatomyositis.

Progressive multifocal leucoencephalopathy (PML), a demyelinating disease caused by the JC virus (JCV), occurs in immunosuppressed patients and carries a poor prognosis. A favourable outcome is reported in two patients with PML and dermatomyositis. Immunosuppressive drugs were stopped in patient 1 but could only be partially tapered in patient 2. The JCV-specific CD8+ T cell response was strong in patient 1 and weak in patient 2. Both were treated with cytosine-arabinoside, and patient 2 was also treated with mirtazapine, a 5HT2A receptor antagonist. Combination of these drugs might be helpful to treat HIV-negative patients with PML.

Combined IV-intra-arterial thrombolysis: a color-coded duplex pilot study.

The authors compared the transcranial color-coded duplex pattern of the middle cerebral arteries (MCAs) before and after IV and combined IV-intra-arterial (IV-IA) thrombolysis in consecutive first-ever stroke patients. Patients receiving combined IV-IA thrombolysis showed greater improvement in flow signal and higher incidence of complete MCA recanalization vs those receiving IV thrombolysis, especially when the MCA was occluded or had only minimal flow.

[Status epilepticus and neuronal degeneration: of circuitries and vicious circles]. / Etat de mal épiteptique et neurodégénérescence: entre circuits et cercles vicieux.

The relationship between status epilepticus (SE) and neuronal degeneration is quite complex and difficult to investigate. Animal studies suggest that SE induces a progressive neuronal death; however, clinical observations on humans are less uniform: generalized SE may precede the development of hippocampal sclerosis, but other forms (such as simple-partial or complex-partial) seem less ominous. On the other side, SE can be encountered in many patients with neurodegenerative disorders, particularly those with severe forms. It is thus likely that SE represents a sign, rather than an aetiology, of clinical gravity. Therefore, while it is ancillary to treat rapidly any SE form, the therapeutic approach, especially the use of aggressive treatments, should be tailored according to the underlying medical conditions.

Double dissociation between representational personal and extrapersonal neglect.

BACKGROUND: Although perceptual and representational neglect are frequently associated, the demonstration of a double dissociation between both neglect forms suggests that both rely on different central mechanisms. In addition, perceptual neglect can be selectively observed within personal space or extrapersonal space. However, it is not known whether the latter dissociation also exists in representational neglect. METHODS: The authors investigated this question in two brain-damaged patients with anatomically different lesions sites, using neuropsychological tests specifically designed to assess perceptual and representational neglect in both personal and extrapersonal space. RESULTS: Patients presented a double dissociation with respect to personal and extrapersonal space in representational neglect. CONCLUSIONS: These data suggest that the cerebral networks that process mental space representation use similar principles of space compartmentalization as those used by cerebral networks processing perceived space.

Transient hemiageusia in cerebrovascular lateral pontine lesions.

Knowledge of human central taste pathways is largely based on textbook (anatomical dissections) and animal (electrophysiology in vivo) data. It is only recently that further functional insight into human central gustatory pathways has been achieved. Magnetic resonance imaging studies, especially selective imaging of vascular, tumoral, or inflammatory lesions in humans has made this possible. However, some questions remain, particularly regarding the exact crossing site of human gustatory afferences. We present a patient with a pontine stroke after a vertebral artery thrombosis. The patient had infarctions in areas supplied by the anterior inferior cerebellar artery and showed vertical diplopia, right sided deafness, right facial palsy, and transient hemiageusia. A review of the sparse literature of central taste disorders and food preference changes after strokes with a focus on hemiageusia cases is provided. This case offers new evidence suggesting that the central gustatory pathway in humans runs ipsilaterally within the pons and crosses at a higher, probably midbrain level. In patients with central lesions, little attention has been given to taste disorders. They may often go unnoticed by the physician and/or the patient. Central lesions involving taste pathways seem to generate perceptions of quantitative taste disorders (hemiageusia or hypogeusia), in contrast to peripheral gustatory lesions that are hardly recognised as quantitative but sometimes as qualitative (dysgeusia) taste disorders by patients.

Speech arrest with stimulation may not reliably predict language deficit after epilepsy surgery.

The authors present a patient in whom electrical cortical stimulation of the posterior temporal cortex induced speech arrest, comprehension deficits, and other language-related impairments. This area was ultimately resected because of persistence of a severe seizure disorder. No postoperative aphasia was observed despite the cortical stimulation results, and the patient is since seizure free. These findings question the well-established principle that corticography directly reflects local cortical functions in all patients.

Blinking and schizotypal thinking.

Spontaneous eye blink rate (SBR) is thought to be a biological marker for cerebral dopamine (DA) activity. Accordingly, positive psychotic symptoms have been found to be associated with an increased SBR and negative psychotic symptoms with a decreased SBR. However, modulations of the DA system in patient populations also result from prior neuroleptic treatment. Here, we tested the possible relationship between SBR and positive and negative schizotypal thought. To test the direct influence of DA on SBR in general and as a function of schizotypy, half of a sample of 40 healthy men received levodopa and the other half placebo in a double-blind procedure. SBR did not differ between substance groups suggesting that a pharmacologically induced DA increase in healthy individuals does not generally increase SBR. However, in the levodopa group, increasing SBR correlated with increasing negative schizotypy scores, while no relationship was found between SBR and (1) negative schizotypy in the placebo group, or (2) positive schizotypy in either substance group. We conjecture that a pre-existing hypodopaminergic state in high negative schizotypy scorers, made these individuals susceptible to an increased DA concentration, as it has been observed in Parkinson's disease. Furthermore, the absence of any relationship in the placebo group might suggest that variations in DA concentration as a function of schizotypy are too subtle to influence SBR. Finally, the lack of any association of SBR with positive schizotypy might indicate that SBR and positive schizotypy are mediated by functionally distinct neural circuits.