[Geriatric particularities of Parkinson's disease: Clinical and therapeutic aspects]

Parkinson's disease (PD) is a frequent and complex progressive neurological disorder that increases in incidence with age. Although historically PD has been characterized by the presence of progressive dopaminergic neuronal loss of the substantia nigra, the disease process also involves neurotransmitters other that dopamine and regions of the nervous system outside the basal ganglia. Its clinical presentation in elderly subjects differs from that in younger subjects, with more rapid progression, less frequent tremor, more pronounced axial signs, more frequent non-motor signs linked to concomitant degeneration of non-dopaminergic systems, and more frequent associated lesions. Despite the high prevalence of PD in elderly subjects, few therapeutic trials have been conducted in geriatric patients. Nevertheless, to improve functional disability while ensuring drug tolerance, the principles of optimized and multidisciplinary clinical management have to be known. The aim of this review is to provide an update on clinical and therapeutic features of PD specifically observed in elderly subjects.

[Normal pressure hydrocephalus: A review and practical aspects]

Idiopathic normal pressure hydrocephalus is a chronic disorder affecting the elderly. It is defined by Adams and Hakim's triad in addition to ventricular dilation visible by brain imaging and normal cerebrospinal fluid pressure during lumbar puncture. The objective of this review was to propose a standard of care for idiopathic normal pressure hydrocephalus based on an extensive literature review conducted on 459 articles published over the last 10 years. Those articles were obtained by searching for the keywords "normal pressure hydrocephalus" in the PubMed database and selecting all the articles published in English or in French. The diagnosis of idiopathic normal pressure hydrocephalus is difficult because of commonly associated diseases, such as Alzheimer's disease and microangiopathy. Brain MRI is one of the key procedures to assist in the diagnosis of idiopathic normal pressure hydrocephalus. Indeed, the presence of certain MRI features is highly predictive of a positive tap test and shunt responsiveness. Nevertheless, tap test remains the standard of care for diagnosis. Continuous cerebrospinal fluid drainage test is an alternative because it improves the sensitivity of diagnosis (but is a more complicated test to perform). Alzheimer's biomarkers dosing in the cerebrospinal fluid seems interesting when diagnosis remains uncertain: the presence of Alzheimer's profile of the biological markers is predictive of a lower response to the tap test.

Neuroinflammation and β amyloid deposition in Alzheimer's disease: in vivo quantification with molecular imaging

BACKGROUND/AIMS

Neuroinflammation plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Its relationship with underlying β amyloid deposition remains unclear. In vivo visualization of microglial activation has become possible with the development of molecular imaging ligands when used with positron emission tomography (PET). The translocator protein (TSPO) is upregulated during neuroinflammation. Consequently, targeting TSPO with radiolabeled ligands for PET is an attractive biomarker for neuroinflammation.

METHODS

A review of the research literature on PET imaging which studied in vivo neuroinflammation in AD subjects and its relationship with amyloid load was performed, including papers published between 2001 and 2012.

RESULTS

Six studies were included using either [(11)C]PK-11195 or another non-TSPO radioligand that binds to the monoaminooxidase B. All the studies evaluated amyloid load with [(11)C]PIB. Microglial activation and astrocytosis are potentially early phenomena in AD. However, the individual levels of amyloid deposition and microglial activation were not correlated.

CONCLUSION

Noninvasive in vivo molecular imaging to visualize neuroinflammation in AD may contribute to our understanding of the kinetics of neuroinflammation and its relationship to the hallmarks of the disease. Both are important for the development of future therapeutic modalities and for quantifying the efficacy of future disease-modifying treatments.

Cerebral functional asymmetry and phonological performance in dyslexic adults

Developmental dyslexia is a frequent language-based learning disorder characterized by difficulty in reading. The predominant etiologic view postulates that reading impairment is related to phonological and orthographic dysfunction. The aim of this fMRI study was to evaluate the neural bases of phonological processing impairment in remediated dyslexic adults (DD). We used a rhyming words judgment task contrasted with an unreadable fonts font-matching judgment task to compare patterns of activation and functional asymmetry in DD and normal-reading young adults. We found evidence of a link between asymmetry in inferior frontal gyrus and performance during the phonological processing. We also observed that DD recruit a network including regions involved in articulatory control in order to achieve rhyme judgment suggesting that, due to a lack of hemispheric specialization, DD recruit the latter network to achieve rhyme judgment.

Review of cerebral microangiopathy and Alzheimer's disease: relation between white matter hyperintensities and microbleeds

Although Alzheimer's disease (AD) is basically considered to be a neurodegenerative disorder, cerebrovascular disease is also involved. The role of vascular risk factors and vascular disease in the progression of AD remains incompletely understood. With the development of brain MRI, it is now possible to detect small-vessel disease, whose prevalence and severity increase with age. The first types of small-vessel disease to be described were white matter hyperintensities (WMHs). More recently, small areas of signal loss on T(2)*-weighted images, also called microbleeds (MBs), have been reported. Cerebral MBs are focal deposits of hemosiderin that indicate prior microhemorrhages around small vessels, related to either ruptured atherosclerotic microvessels or amyloid angiopathy. Consequently, using brain MRI for the detection of microangiopathy may prove useful to improve our understanding of the impact of the vascular burden in AD pathology. The relationship between microangiopathy and the clinical course of AD or the conversion of mild cognitive impairment to AD remains questionable in terms of cognitive or affective symptoms, particularly if we consider MBs.

Influence of age on the dynamics of fMRI activations during a semantic fluency task

PURPOSE

Age-related fMRI changes have not been extensively studied for language, whereas important adaptive mechanisms have been seen in other cognitive fields. This study examined age-related changes in fMRI activation during language tasks and, in particular, their dynamic course.

PATIENTS AND METHODS

fMRI was performed on 22 young and 21 old healthy right-handed subjects during a silent category word-generation task. Activation and dynamics of BOLD signals were studied separately during the first and second portions of each 30-s block.

RESULTS

Activation of the left frontal lobe was initially similar in young and old participants; however, it decreased after 30 s in the old participants. On the other hand, additional areas were initially involved only in old subjects and especially in the default mode network.

CONCLUSION

This study showed age-related differences in the dynamics of fMRI activation during a silent word-generation task, suggesting a different pattern of language function with aging.

Central auditory processing in aging: the dichotic listening paradigm

OBJECTIVE

Aging is associated with cognitive changing. Central auditory processing dysfunction may explain some understanding difficulties in elderly. It may be evaluated with the dichotic listening (DL) test, a widely-used experimental paradigm for studying inter-hemispheric interactions and attentional processes. This study examines central auditory language processing with a dichotic listening task in right-handed old subjects according to their age.

DESIGN

Cross sectional-study.

SETTING

memory clinic and geriatric unit.

PARTICIPANTS

Adult group (Ad) consisted in 26 subjects (21 women and 5 men) aged 50-69 years and an old adults group (Old-Ad) consisted in 20 subjects (19 women and 1 man) aged 70 to 89 years.

MEASUREMENTS

DL consisted in a free-recall word task and a digit forced-attention task (forced-right: FR and forced-left: FL) in order to study central auditory language processing. In addition, we used neuropsychological tests to study executive functions and cognitive control, sustained by the prefrontal cortex.

RESULTS

In the free recall condition, we confirmed the classic right ear advantage (REA) in both groups, particularly in older subjects. In the forced condition, we observed an ear advantage with a change in ear asymmetry as a consequence of instruction: REA in FR and a left-ear advantage (LEA) in FL. We compared contaminations by the contra-lateral inattentive ear: reports of the left ear (LE) in the FR condition and reports of the right ear (RE) in the FL condition. Contaminations by the RE in the FL condition were more pronounced in Old-Ad suggesting difficulties in competition between the natural tendency for the RE and the instruction. In the Old-Ad group, the correlation between the RE score in FL and TMT B-A/A suggests an impairment in mental flexibility.

CONCLUSION

DL may be helpful to study central auditory dysfunction in aging. Our results suggest difficulties in attentional control and executive functions. Central auditory dysfunction should be evaluated in elderly because it potentially contributes to difficulty of hearing in noisy environment with consequences in the rehabilitation of presbyacousic subjects. More studies are needed to investigate the predictive value of DL as a marker of cognitive decline, particularly executive functions.

The FHM1 Mutation S218L: A Severe Clinical Phenotype? A Case Report and Review of the Literature

Familial hemiplegic migraine (FHM) is a rare autosomal dominant subtype of migraine with aura that is characterized by motor weakness during attacks. FHM1 is associated with mutations in the CACNA1A gene located on chromosome 19. We report a severe, prolonged HM attack in a young pregnant patient who had the S218L FHM1. This CACNA1A mutation has been associated with HM, delayed cerebral oedema and coma following minor head trauma. The case history we report suggests a specific, severe phenotype and the co-occurrence of HM and epilepsy related to the S218L FHM1 mutation.

Epilepsy and dementia in the elderly

Epilepsy is a frequent condition in the elderly; however, it remains a relatively understudied condition in older adults with dementia. The diagnosis of a seizure is particularly difficult and is most often based on questions to the caregiver. Epilepsy in dementia has significant consequences on the prognosis of the underlying dementia: it can result in a worsening of cognitive performance, particularly in language, as well as a reduction in autonomy, a greater risk of injury and a higher mortality rate. In this review, management strategies are recommended for the clinician. The presence of pre-existing Alzheimer's disease does not exempt the clinician from ruling out other symptomatic causes of seizures. Anti-epileptic drugs (AED) should be started only after the diagnosis has been clearly established, when the risk of recurrence is high, and with monotherapy whenever possible. Although few data are available, the more recent AED offer significant advantages over the older medications in this context.

Visual recognition memory differentiates dementia with Lewy bodies and Parkinson's disease dementia

OBJECTIVE

To compare cognitive impairments in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), to discriminate between the two entities.

METHODS

10 DLB and 12 PDD consecutive patients performed a neuropsychological battery designed to assess several cognitive domains: verbal and visual memory (Delayed Matching to Sample (DMS)-48), language, gnosia, praxia and executive functions.

RESULTS

DLB patients had poorer performances in orientation (p<0.05), Trail Making Test A (p<0.05) and reading of names of colours in the Stroop Test (p<0.05). Their scores were also lower in the visual object recognition memory test (DMS-48), in both immediate (p<0.05) and delayed recognition (p<0.05). No differences were observed in the other tests.

CONCLUSION

Despite global similarities in cognitive performances between DLB and PDD patients, we observed important differences: in particular, DMS-48, a test of visual object recognition memory and visual storage capacity, was poorer in DLB patients.

Transient global amnesia caused by painless aortic dissection

Neurological syndromes secondary to acute aortic dissection (AAD) are uncommon and usually consist of focal deficits after an embolic cerebral infarction. This article reports the observation of an AAD with the chief complaint of transient acute memory impairment-that is, a non-usual stroke-like symptom.

Malformations corticales et épilepsie : apport de l’IRM

Malformations of cortical development are increasingly recognized as important causes of epilepsy, developmental delay and other neurological disorders. Our purpose is to present the relevance of the MRI in these pathologies with the clinical, genetic and therapeutic aspects. This classification is based on the three fundamental events of cortical formation: proliferation of neurons and glie in the periventricular zone, migration of postmitotic neurons to the periphery, subsequent cortical organization. MR analysis evaluates particularly the cortical thickness, sulcal and cortical morphology, gray-white matter junction, and looks for gray matter in abnormal location. These data coupled with the familial history, the seizure characteristics and genetic findings should allow an appropriate classification of the lesions. MR imaging allows the detection and classification of cortical malformations. MR imaging findings are primordial to consider surgery when the epilepsy becomes refractory to the anti-epileptic drugs. An adequate classification of these malformations should help to provide to the family an appropriate counseling both in terms of genetics and outcome.

[Treatment of an intracerebral mycotic aneurysm with embolisation]

We report the case of a patient with streptococcal mitral endocarditis discovered following an ischaemic cerebrovascular accident. The clinical evolution was marked by the progressive development of a mycotic aneurysm. Surveillance was performed with repeated angio-MRI which provided an indication for embolisation. We demonstrate the value and the current quality of angio-MRI for the diagnosis of mycotic aneurysms, and the value of active management of these lesions which present a high risk of rupture and which are associated with a significant excess mortality. Embolisation can allow earlier cardiac surgery for haemodynamically unstable patients and for those whose neurological state until now contra-indicated intervention.

P-ANCA cranial pachymeningitis: a case report

Pachymeningitis is an inflammatory process that thickens the dura mater. This disease has various etiologies including infectious, neoplastic, or autoimmune diseases. We present the case of a patient who developed cranial pachymeningitis with a clinical and biological picture suggestive of a neurological form of vasculitis. A 51-year-old woman developed rhinitis, otitis media, headaches, and deterioration of her condition after a course of recombinant hepatitis B vaccine. After a booster dose of the vaccine, she developed unilateral visual loss and impairment of multiple cranial nerves. Blood analysis showed inflammation and presence of antimyeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA). Cranial magnetic resonance imaging (MRI) showed pachymeningitis. A complete remission was obtained with immunosuppressive therapy. The initial clinical presentation and subsequent remission under immunosuppressive therapy were suggestive of a vasculitis with nervous system involvement. Though vasculitis was not proven histologically in this patient, we believe that MPO-ANCA-related autoimmunity provoked the patient's disease as already reported in similar cases. As pachymeningitis is a fibrosing process, early recognition and treatment of an autoimmune etiology, even in the absence of previous pulmonary or renal involvement, is required to prevent definitive neurological impairment.

Adult onset ornithine transcarbamylase deficiency: an unusual cause of semantic disorders

Ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle disorder. This condition usually presents in neonates or children. This report describes the clinical case of a 21 year old woman who was diagnosed in adulthood during the course of an unexplained coma. After recovery from the coma, she presented very unusual neuropsychological disorders involving memory and the meaning of certain words, suggesting a semantic deficit. The discovery of OTCD in adulthood is rare and the neuropsychological consequences may be unique.

Unilateral spatial neglect following right inferior parietal cortectomy

Research in brain-damaged patients has suggested that the right hemisphere plays a role in unilateral spatial neglect (USN), but provides only limited information for pinpointing the intraparietal localization of the lesions associated with this syndrome. We report a case of unilateral neglect in a patient who underwent a right inferior parietal cortectomy for refractory epilepsy without any macroscopic lesion. We describe the evolution of the neuropsychological disturbances observed at 3 and 24 months after cortectomy. This case illustrates the role played by the inferior parietal lobe and, particularly, the parietal opercule in USN syndrome, and provides strong "experimental" evidence of the special role played by the inferior parietal lobule in the perception processes related to spatial attention.

[Functional brain lateralization in children: developmental theories and implication for developmental diseases]

The functional specialization of each hemisphere in adults is now well accepted. Neuropsychology of hemispheric functioning in young children is a more debatable issue and must take into account additional factors such as development and maturation, characterized by complex changes in anatomy and organization. The first part of this review describes the theory behind the development of the functional organization of the brain. Second, we discuss data regarding brain lesions in children with brain damage and with normal development. We comment on the concept of plasticity and the critical period. We also discuss the neurobiological processes underlying the functional organization of the brain in the model of developmental disorders in children. We chose three disorders involving the left hemisphere (developmental dysphasia), both hemispheres (benign rolandic epilepsy) or the right hemisphere (congenital hydrocephalus) in order to examine their relationship to a specific hemispheric functional organization. We used classic neuropsychological tests such as the dichotic listening task, the dichaptic palpation and the time-sharing paradigm. The patterns observed in each pathology are discussed in light of data obtained in children with brain lesions.

[Hemimegalencephaly: a misleading EEG tracing]

Hemimegalencephaly is a rare cerebral malformation that usually presents with mental retardation, controlateral hemiparesis and intractable seizures. We report a case of hemimegalencephaly diagnosed in adulthood based on MRI findings. The electroencephalogram initially suggested partial status epilepticus. The diagnosis of this cerebral malformation has been made easier thanks to recent progress in cerebral imagery with MRI. We describe and discuss the relevant encephalographic aspects.

MRI morphometric study and correlation with cognitive functions in young adults shunted for congenital hydrocephalus related to spina bifida

We studied the morphometric MRI findings and their correlation with cognitive functions in a population of 10 young adults shunted for congenital hydrocephalus related to spina bifida. Morphometric MRI analysis included measurement of the ventricular dilatation index, frontal and occipital parenchymal thickness and the size of the corpus callosum. The neuropsychological status was evaluated, notably to look for a discrepancy between verbal and performance skills, a finding which has previously been described in hydrocephalic children. We also investigated whether there was a correlation between cognitive function and cerebral morphometric indexes. In each case, MRI demonstrated the structural changes associated with the Chiari II malformation. The size of the lateral ventricles varied, ranging from important dilatation to small ventricles. Six patients had only partial development of the corpus callosum. All patients had a normal global IQ. In our population of young adults, we did not observe any discrepancy between verbal and visuospatial performances as has been described in children with hydrocephalus. We found no relationship between cognitive function and ventricle dilatation or parenchymal thickness or between the size of the corpus callosum and callosal transfer.

Cognitive function in adolescents and young adults in complete remission from benign childhood epilepsy with centro-temporal spikes

Benign childhood epilepsy with centrotemporal spikes (BECTS) is a frequent, benign childhood epilepsy with a good prognosis. However, neuropsychological deficits have been reported during its active phase. In this study, we evaluate the long-term neuropsychological consequences of this reputedly benign epilepsy, particularly the relation between paroxysmal abnormalities and cerebral language lateralization. The neuropsychological outcomes concerning both overall cognitive and lateral hemispheric functions were studied in twenty-three adolescents and young adults in total recovery from BECTS, in thirty-three controls without any significant past neurological history and in ten adolescents and young adults with complete resolution of generalized idiopathic epilepsy (childhood absence epilepsy or CAE). Language lateralization was evaluated using classical neuropsychological procedures (dichotic listening tasks, dual-task procedure). No difference was seen in the three populations with respect to overall cognitive function: memory, language and the executive functions. Although the Performance IQ was lower in patients in remission from CAE, the results were within normal limits. However, qualitative analysis of the dual-task procedure suggested a different organizational pattern for cerebral language in adolescents and young adults in remission from BECTS as compared to controls and patients in remission from CAE. The different organization in cerebral pattern in BECTS patients appeared to be related to the initial epileptic focus as determined by the EEG and/or the sleep-recording. We discuss the relationship between the presence of paroxysmal anomalies in childhood and subtle functional lateralized hemispheric abnormalities in adulthood.

Sleep and brain lesions: a critical review of the literature and additional new cases

We present a comprehensive review of sleep studies performed in patients with brain lesions complemented by 16 additional personal selected cases and by discussion of the corresponding animal data. The reader is cautioned about the risk of establishing an erroneous correlation between abnormal sleep and a given disorder due to the important inter and intra variability of sleep parameters among individuals. Salient points are stressed: the high frequency of post-stroke sleep breathing disorders is becoming increasingly recognised and may, in the near future, change the way this condition is managed. Meso-diencephalic bilateral infarcts induce a variable degree of damage to both waking and non-REM sleep networks producing and abnormal waking and sometimes a stage 1 hypersomnia reduced by modafinil or bromocriptine, which can be considered as a syndrome of cathecholaminergic deficiency. Central pontine lesions induce REM and non-REM sleep insomnia with bilateral lateral gaze paralysis. Bulbar stroke leads to frequent sleep breathing disorders. Polysomnography can help define the extent of involvement of various degenerative diseases. Fragmented sleep in Parkinson's disease may be preceded by REM sleep behavioural disorders. Multiple system atrophies are characterised by important sleep disorganization. Sleep waking disorganization and a specific ocular REM pattern are often seen in supra-nuclear ophtalmoplegia. In Alzheimer patients, sleep perturbations parallel the mental deterioration and are possibly related to cholinergic deficiency. Fronto-temporal dementia may be associated with an important decrease in REM sleep. Few narcoleptic syndromes are reported to be associated with a tumour of the third ventricle or a multiple sclerosis or to follow a brain trauma; all these cases raise the question whether this is a simple coincidence, a revelation of a latent narcolepsy or, as in non-DR16/DQ5 patients, a genuine symptomatic narcolepsy. Trypanosomiasis and the abnormal prion protein precociously after sleep patterns. Polysomnography is a precious tool for evaluating brain function provided it is realised under optimal conditions in stable patients and interpreted with caution. Several unpublished cases are presented: one case of pseudohypersomnia due to a bilateral thalamic infarct and corrected by modafinil, four probable late-onset autosomal recessive cerebellar ataxias without sleep pattern anomalies, six cases of fronto-temporal dementia with strong reduction in total sleep time and REMS percentage on the first polysomnographic night, one case of periodic hypersomnia associated with a Rathke's cleft cyst and four cases of suspected symptomatic narcolepsy with a DR16-DQ5 haplotype, three of which were post-traumatic without MRI anomalies, and one associated with multiple sclerosis exhibiting pontine hyper signals on MRI.

[Primary hypereosinophilia syndrome manifesting as encephalopathy and vision disorders]

We report the case of a 60-year-old man who developed visual and cognitive disorders. Investigations confirmed the diagnosis of idiopathic hypereosinophilic syndrome even though the patient had a history of rectal cancer. The olinical course was favorable after treatment. We discuss the different clinical forms, imaging data and treatments of eosinphilic syndrome.

Continuous spikes and waves during slow sleep (CSWS): outcome in adulthood

We report a longitudinal, electroencephalographic and neuropsychological analysis of epilepsy with continuous spikes and waves during slow sleep (CSWS) in a 19 year-old boy. The clinical course fluctuated, with temporary worsening or improvement of the paroxysmal abnormalities, epilepsy and cognitive functions. At the end of the follow-up period, seizures persisted. Evaluation of the boy's behaviour, language and cognitive function suggested a dysexecutive syndrome. We discuss the relationship between paroxysmal abnormalities and neuropsychological disorders.

[Tumors of the neuraxis and neuraxial sheaths during pregnancy (excluding tumors of the sellar region)]

An association between central nervous system neoplasm and pregnancy is uncommon although its frequency is underestimated. The most commonly observed tumors are acoustic neuromas, meningiomas and gliomas. The interactions between these tumors and pregnancy is not well known : Pregnancy could affect tumor growth by : - activating tumor growth by stimulating receptors; - increasing the peritumoral edema; - favoring immunotolerance due to pregnancy. Steroid hormone receptors and their therapeutic significance are described here, focusing particularly in meningiomas. Central nervous system tumors do not effect the progress of pregnancy per se but do the therapeutic implications. The clinical aspects are the same as in non-pregnant women. MRI appears to be the most adapted imaging technique. Neurosurgical guidelines are also described, with emphasis on symptomatic therapeutics, especially for seizure. Attitudes concerning the nature of the tumor and time of pregnancy are then discussed. The obstetrical attitude should be therapeutic abortion or delivery, with cesarean if necessary. Prognosis is getting better for the child and mother alike, but still remains poor.

[Amyotrophic lateral sclerosis manifesting as cognitive disorders. Value of brain perfusion scintigraphic tomography in intensive care]

BACKGROUND

Cognitive disorders have been described in amyotrophic lateral sclerosis, but usually after the diagnosis has ben established.

CASE REPORT

A 57-year-old man was intubated for acute respiratory distress subsequent to pneumonia and diaphragm palsy. He had a 2-year history of drug-resistant depression and deterioration of cognitive functions. A pyramidal syndrome associated with biopsy-proven chronic neurogenic atrophy led to the diagnosis of amyotrophic lateral sclerosis. The electromyogram did not contribute to diagnosis. Brain MRI only evidenced moderate bilateral frontal-temporal atrophy. Brain SPECT demonstrated major perfusion defects in the frontal lobes.

DISCUSSION

This patient had amyotrophic lateral sclerosis and frontal-temporal dementia with an unusually late onset clinical presentation: cognitive disorder was the inaugural sign. Brain SPECT and muscle biopsy enabled us to identify the cortical and peripheral motor neurone involvement in this uncooperative intensive care patient totally dependent on mechanical ventilation.

[Determination of language dominance using EEG spectral analysis versus the Wada test in temporal epilepsy (right-handed subjects)]

Spectral analysis of the EEG alpha rhythm was studied in nine temporal epileptic right-handed patients in order to predict localization of the speech area. We studied the variation of the spectral power of the alpha rhythm during an activation paradigm previously validated in normal right-handed subjects. Significant alpha power decreases in the left hemisphere during writing with the right hand (as compared to resting) and/or significant alpha power decreases in the right hemisphere during left-hand recognition and classification of cardboard objects (as compared to resting) were considered as consistent with left-hemisphere dominance for language. The results of EEG spectral analysis were compared with those of the Wada test. The left hemisphere was dominant for language according to the Wada test in eight subjects and the right hemisphere in one subject. Six patients had a significant alpha power reduction in the hemisphere concerned during lateralized cognitive tasks, consistent with language localization in the left hemisphere according to the Wada test. The three remaining patients had no significant EEG spectral power variations. A significant decrease of alpha power in the active hemisphere during cerebral activation seems statistically related to left-hemispheric dominance for language in right-handed subjects (hemispheric specialization). However, the localization of the speech area using this electrophysiological method does not appear clinically relevant for a case-by-case decision in individual patients.

Sleep and epilepsy

This review considers the effect of sleep on seizures and interictal electroencephalogram (EEG) paroxysmal activities (PAs), as classified by the International League Against Epilepsy criteria. No type of seizure is, per se, specifically linked with non-rapid eye movement (NREM) or rapid eye movement (REM) sleep. However, in some syndromes, seizures are more frequent in slow wave sleep (SWS) [partial motor or generalized seizure in benign epilepsy with centro-temporal spikes (BECTS), frontal seizures in idiopathic familial or not familial frontal lobe epilepsy and generalized tonic seizure in secondary generalized epilepsy are increased by SWS]. Conversely myoclonia and grand mal seizures are associated with awakening in some forms of generalized idiopathic epilepsy. There is a mean increase in PAs during SWS in generalized and in partial epilepsies on the whole. However, precise analysis shows that in partial cryptogenic or symptomatic epilepsy and, most likely, in the majority of generalized idiopathic epileptic syndromes about 20% of patients have an increase in PA density during SWS, 20% experience an increase in waking, 50% have very few PAs and in 10% there is no significant difference between sleep and waking. BECTS, however, exhibits a definite increase in sleep PA increase and in juvenile myoclonic epilepsy an increase in PAs during the intra-night awakening is reported. There are at least three syndromes, which cause a huge increase in PAs during sleep: the Landau-Kleffner syndrome and the syndromes of continuous focal or generalized spike-waves during SWS. Their physiopathology and neuropsychological consequences are discussed. Neurophysiological animal data are also reported highlighting the relationships between slow sleep oscillations and the generation of spike waves. A biochemical review is also presented.

Hemianopsia related to dissection of the internal carotid artery

Spontaneous dissection of the internal carotid artery is typically associated with cerebral vascular infarction along the anterior and middle cerebral distribution, whereas occipital infarction is usually related to posterior circulation abnormalities. Hemianopsia with occipital infarction related to carotid artery dissection has therefore rarely been reported. A 40-year-old woman in whom acute-onset hemianopsia developed, related to occipital infarction secondary to internal artery dissection, is described. This atypical association is explained by anatomic variations of the posterior part of the circle of Willis. Neuroimages showed occipital infarction related to internal carotid artery dissection associated with hypoplasia of the proximal portion of the cerebral posterior artery (P1). The anatomic correlation of this atypical association and a review of the literature are presented.

Neuropsychologic and adaptive functioning in adolescents and young adults shunted for congenital hydrocephalus

The major aim of this study was to assess whether the syndrome of nonverbal learning disabilities described in hydrocephalic children is observed in adulthood. Eleven adults shunted for congenital hydrocephalus related to spina bifida and eight adults shunted for hydrocephalus related to aqueductal stenosis were administered an extensive neuropsychologic battery to investigate discrepancies between verbal and visuospatial cognition, verbal and visuospatial long-term memory, and psycho-social adaptive abilities. The results showed no discrepancies between Wechsler Performance IQ or Verbal IQ in either hydrocephalic group. Nevertheless, the subjects with spina bifida appeared more cognitively impaired than the subjects with aqueductal stenosis, who performed normally on the Wechsler Adult Intelligence Scale-Revised. Memory assessment using Signoret's Memory Battery revealed no discrepancy between verbal and visuospatial memory in the hydrocephalic group. Nevertheless, the subjects with spina bifida had poorer verbal and visuospatial memory performance than the subjects with aqueductal stenosis. There were no differences on the Vineland Adaptive Behavioral Scale between subjects with spina bifida and those with aqueductal stenosis in autonomy, socialization, and daily living skills. These results suggest that shunted congenital hydrocephalus is not characterized by nonverbal learning disabilities syndrome in adolescence or in adulthood.