Morphometric evaluation of the hydrocephalic brain: relationships with cognitive development

The effects of early hydrocephalus and related brain anomalies on cognitive skills are not well understood. In this study, magnetic resonance scans were obtained from 99 children aged from 6 to 13 years with either shunted hydrocephalus (n=42) or arrested (unshunted) hydrocephalus (n=19), from patient controls with no hydrocephalus (n=23), and from normal, nonpatient controls (n=15). Lateral ventricle volumes and area measurements of the internal capsules and centra semiovale in both hemispheres were obtained from these scans, along with area measurements of the corpus callosum. Results revealed reductions in the size of the corpus callosum in the shunted hydrocephalus group. In addition, lateral ventricle volumes were larger and internal capsule areas were smaller in both hemispheres in children with shunted and arrested hydrocephalus. The centra semiovale measurements did not differentiate the groups. Correlating these measurements with concurrent assessments of verbal and nonverbal cognitive skills, motor abilities, and executive functions revealed robust relationships only between the area of the corpus callosum and nonverbal cognitive skills and motor abilities. These results support the theory of a prominent role for the corpus callosum defects characteristic of many children with shunted hydrocephalus in the spatial cognition deficits commonly observed in these children.     

Functioning of the corpus callosum in children with early hydrocephalus.

The development and organization of the corpus callosum is described as well as the relationship between the timing of insults and the type of partial agenesis of the corpus callosum are discussed. Neuropathology and callosal damage associated with spina bifida meningomyelocele, aqueductal stenosis, and prematurity-IVH are outlined. Relationships between corpus callosum/whole brain ratios and cognitive functioning as well as interhemispheric transfer in children with these disorders are outlined. Shortcomings of current research and future directions are suggested.     

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.     

Interhemispheric transfer of visual, auditory, tactile, and visuomotor information in children with hydrocephalus and partial agenesis of the corpus callosum

Interhemispheric transfer was examined in 13 normal controls and in 13 children with hydrocephalus and partial agenesis of the corpus callosum involving a missing splenium associated with spina bifida meningomyelocele and aqueductal stenosis. Children with hydrocephalus demonstrated greater left visual-field superiority for forms indicative of difficulty in interhemispheric transfer of visual information. Interhemispheric transfer time (ITT) was somewhat longer in the children with hydrocephalus, but neither the ITT task nor the dichotic listening and tactile naming tasks provided clear evidence of difficulties in callosal transfer. Sensory and perceptual control tasks revealed similar visual acuity and monotic word perception but larger 2-point discrimination thresholds and poorer tactile matching.     

Interhemispheric Transfer of Visual,Auditory, Tactile,and Visuomotor Information in Children with Hydrocephalus and Partial Agenesis of the Corpus Callosum

Interhemispheric transfer was examined in 13 normal controls and in 13 children with hydrocephalus and partial agenesis of the corpus callosum involving a missing splenium associated with spina bifida meningomyelocele and aqueductal stenosis. Children with hydrocephalus demonstrated greater left visual-field superiority for forms indicative of difficulty in interhemispheric transfer of visual information. Interhemispheric transfer time (ITT) was somewhat longer in the children with hydrocephalus, but neither the ITT task nor the dichotic listening and tactile naming tasks provided clear evidence of difficulties in callosal transfer. Sensory and perceptual control tasks revealed similar visual acuity and monotic word perception but larger 2-point discrimination thresholds and poorer tactile matching.     

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.     

Verbal and nonverbal skill discrepancies in hydrocephalic children

Abstract

This study evaluated a large sample (N = 90) of 5- to 7-year-old children with hydrocephalus caused by aqueductal stenosis or prematurity-intraventricular hemorrhage or associated with spina bifida. Comparison groups of normal controls, children with spina bifida and no shunt, and premature children with no hydrocephalus were also evaluated. Comparison of skill discrepancies at two occasions separated by 1 year revealed that hydrocephalic children, as a group, showed poorer nonverbal than verbal skills on measures from the McCarthy Scales of Children's Abilities, the WISC-R and composites of neuropsychological skills. No discrepancies in verbal-nonverbal memory were found nor were any discrepancies attributable to etiology or motor demands of the tasks. Consistent with current hypotheses concerning the role of the cerebral white matter in cognitive development, these results sho the hydrocephalic children in this age range genrally have poorer development of nonverbal cognitive skills relative to their language development.     

Verbal and nonverbal skill discrepancies in hydrocephalic children.

This study evaluated a large sample (N = 90) of 5- to 7-year-old children with hydrocephalus caused by aqueductal stenosis or prematurity-intraventricular hemorrhage or associated with spina bifida. Comparison groups of normal controls, children with spina bifida and no shunt, and premature children with no hydrocephalus were also evaluated. Comparison of skill discrepancies at two occasions separated by 1 year revealed that hydrocephalic children, as a group, showed poorer nonverbal than verbal skills on measures from the McCarthy Scales of Children's Abilities, the WISC-R, and composites of neuropsychological skills. No discrepancies in verbal-nonverbal memory were found nor were any discrepancies attributable to etiology or motor demands of the tasks. Consistent with current hypotheses concerning the role of the cerebral white matter in cognitive development, these results show that hydrocephalic children in this age range generally have poorer development of nonverbal cognitive skills relative to their language development.     

Diencephalic neuronal hamartoma associated with congenital obstructive hydrocephalus, anophthalmia, cleft lip and palate and severe mental retardation: a possible new syndrome

A male infant was born with severe hydrocephalus, bilateral cleft lip/palate, left anophthalmos and right microphthalmos, and an equino-varus foot deformity. Imaging studies showed enlarged lateral ventricles, apparent absence of the corpus callosum and a midline density in the third ventricular region. He had a normal male karyotype. He was severely mentally retarded and died suddenly at 7 years of age. Neuropathological examination of the brain revealed enlarged and polygyric cerebral hemispheres, due to congenital obstructive hydrocephalus, and secondary thinning of the corpus callosum. An unusually large neuronal hamartoma filled the interpeduncular fossa and third ventricle. It was continuous posteriorly with the left thalamus and so was classified as diencephalic rather than as hypothalamic. The right optic nerve merged with the hamartoma, whereas the left nerve was absent. Microscopically the hamartoma consisted of mature grey matter interspersed with narrow bands of white matter. No immature or non-neural elements were identified. This combination of diencephalic neuronal hamartoma, hydrocephalus, ocular and craniofacial abnormalities has not, to our knowledge, previously been described. Received: 9 July 1999 / Revised: 10 September 1999 / Accepted: 14 September 1999     

Effect of endoscopic third ventriculostomy on cerebrospinal fluid pressure in the cerebral ventricles

We aimed to show how endoscopic third ventriculostomy (ETV) treatment may affect cerebrospinal fluid (CSF) flow dynamics in hydrocephalus, with and without aqueductal stenosis. Hydrocephalus is a neurological disorder which is characterized by enlarged brain ventricles. The periodic motion of CSF flow as a function of the cardiac cycle was prescribed as the inlet boundary condition at the foramen of Monro, and ETV was modeled as a 5 mm diameter hole in the anterior wall of the third ventricle. The results show that ETV reduces the pressure in the ventricles by nine-fold in the model with aqueductal stenosis, and three-fold in the model without aqueductal stenosis. More importantly, ETV changes the temporal characteristics of the CSF pressure waveform in the model without aqueductal stenosis, such that there is higher pressure in the ventricle during diastole. This study suggests that changes in the temporal characteristics of the CSF pressure waveform in the ventricles may be the reason why ETV treatment is not effective for hydrocephalus without aqueductal stenosis.     

A rare case of aqueductal stenosis due to venous angioma]

Aqueductal stenosis is induced by widely various causes. These causes include congenital stenosis, tumor or inflammation. Among them vascular malformation is a very rare cause. In this paper we present a rare case of aqueductal stenosis caused by venous angioma. The patient was a 28-year-old female, who suffered from headache and double vision. On admission, CT and MRI showed lateral and third ventricular dilatation not but fourth ventricle, suggested aqueductal stenosis. Gd-DTPA enhanced T1-weighted MR image showed an abnormal draining vein passing through the orifice of the aqueduct. Angiography demonstrated the umbrella sign which was specific sign of the venous angioma. We performed endoscopic third ventriculostomy. Postoperative neuroradiological examination showed shrinkage of the ventricles and the symptom of the patient improved markedly. In the past literatures, five cases of aqueductal stenosis due to venous angioma have been reported. Although venous angioma is congenital, all five cases had been symptomatic at adult stage. Detailed evaluation of pre-and post-operative MRIs suggest that aqueductal stenosis induced enlargement of the lateral and third ventricles, which led narrowing of the suprachiasmatic cistern and the peri-mesencephalic cistern, and downward displacement of medulla and tonsil into the foramen magnum. As a result, hydrocephalus is aggravated gradually.     

Magnetic resonance imaging in agenesis of the corpus callosum

The recent use of computed tomography (CT) scan is providing an easy diagnoses of agenesis of corpus callosum which had been difficult to diagnose only by clinical signs and symptoms. Since, more neuropsychological studies on agenesis of corpus callosum are being done, clinical details of agenesis of corpus callosum are being clarified. We examined magnetic resonance imaging (MRI) on 3 patients who were suspected to have agenesis of corpus callosum by CT scan. And we studied the usefulness of MRI in agenesis of corpus callosum. Case 1. We studied a thirty-two-year-old right-handed man with a one-year history of amyotrophic lateral sclerosis. He had no callosal disconnection syndrome. CT scan on horizontal view showed dilated third ventricle, the dilatation of the occipital horns and wide separation of the lateral ventricles. On coronal view, CT scan showed the absence of the corpus callosum, the concave mesial borders of the lateral ventricle, the dilatation of the third ventricle and its abnormal dorsal extent(bat-wing appearance). On sagittal MRI (the inversion recovery technique), the corpus callosum was absent and the convolutions and sulci were arranged radically centering the third ventricle (radial distribution). But the anterior commissure was preserved. Case 2. We studied a fourty-one-year-old right-handed man with a seven-year history of hyper ventilation syndrome. He had no callosal disconnection syndrome. CT scan showed the similar findings as those of case 1. On sagittal MRI (the inversion recovery technique), the corpus callosum was absent, and the convolutions and sulci showed radial distribution. But the anterior commissure was preserved.(ABSTRACT TRUNCATED AT 250 WORDS)     

A.E. Bennett Research Award. Developmental traumatology. Part II: Brain development.

BACKGROUND: Previous investigations suggest that maltreated children with a diagnosis of posttraumatic stress disorder (PTSD) evidence alterations of biological stress systems. Increased levels of catecholaminergic neurotransmitters and steroid hormones during traumatic experiences in childhood could conceivably adversely affect brain development. METHODS: In this study, 44 maltreated children and adolescents with PTSD and 61 matched controls underwent comprehensive psychiatric and neuropsychological assessments and an anatomical magnetic resonance imaging (MRI) brain scan. RESULTS: PTSD subjects had smaller intracranial and cerebral volumes than matched controls. The total midsagittal area of corpus callosum and middle and posterior regions remained smaller; while right, left, and total lateral ventricles were proportionally larger than controls, after adjustment for intracranial volume. Brain volume robustly and positively correlated with age of onset of PTSD trauma and negatively correlated with duration of abuse. Symptoms of intrusive thoughts, avoidance, hyperarousal or dissociation correlated positively with ventricular volume, and negatively with brain volume and total corpus callosum and regional measures. Significant gender by diagnosis effect revealed greater corpus callosum area reduction in maltreated males with PTSD and a trend for greater cerebral volume reduction than maltreated females with PTSD. The predicted decrease in hippocampal volume seen in adult PTSD was not seen in these subjects. CONCLUSIONS: These data suggest that the overwhelming stress of maltreatment experiences in childhood is associated with adverse brain development.     

Structural neuroplasticity in the sensorimotor network of professional female ballet dancers

Evidence suggests that motor, sensory, and cognitive training modulates brain structures involved in a specific practice. Functional neuroimaging revealed key brain structures involved in dancing such as the putamen and the premotor cortex. Intensive ballet dance training was expected to modulate the structures of the sensorimotor network, for example, the putamen, premotor cortex, supplementary motor area (SMA), and the corticospinal tracts. We investigated gray (GM) and white matter (WM) volumes, fractional anisotropy (FA), and mean diffusivity (MD) using magnetic resonance‐based morphometry and diffusion tensor imaging in 10 professional female ballet dancers compared with 10 nondancers. In dancers compared with nondancers, decreased GM volumes were observed in the left premotor cortex, SMA, putamen, and superior frontal gyrus, and decreased WM volumes in both corticospinal tracts, both internal capsules, corpus callosum, and left anterior cingulum. FA was lower in the WM underlying the dancers' left and right premotor cortex. There were no significant differences in MD between the groups. Age of dance commencement was negatively correlated with GM and WM volume in the right premotor cortex and internal capsule, respectively, and positively correlated with WM volume in the left precentral gyrus and corpus callosum. Results were not influenced by the significantly lower body mass index of the dancers. The present findings complement the results of functional imaging studies in experts that revealed reduced neural activity in skilled compared with nonskilled subjects. Reductions in brain activity are accompanied by local decreases in GM and WM volumes and decreased FA. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.     

Magnetic resonance imaging in schizophrenia: altered brain morphology associated with P300 abnormalities and eye tracking dysfunction.

This study was designed to investigate whether auditory P300 event-related potential and smooth pursuit eye-movement abnormalities in schizophrenia are associated with brain structural changes measured using magnetic resonance imaging (MRI). Serial coronal MRI scans obtained from 31 schizophrenic subjects and 33 volunteer controls were analysed by a rater who had no knowledge of the subjects' diagnoses. The brain areas measured bilaterally were the temporal lobe, hippocampus, amygdala, parahippocampal gyrus, head of caudate, cingulate cortex, frontal cortex, and the lateral ventricles. The area of the third ventricle, the thickness of the corpus callosum, and the intracranial area were also measured. Auditory P300 and eye tracking performance were recorded on all subjects. There was a significant increase in the latency and a reduction in amplitude of the P300 in the schizophrenic group. Only in the schizophrenic group was P300 latency correlated negatively with the area of the right and left cingulate cortex and positively with the difference in size between the right and left amygdala. In the subgroup of schizophrenic subjects whose P300 latency was greater than 2 standard deviations above the control mean, the area of the left cingulate cortex was significantly smaller than in controls, and the absolute right-left difference in the area of the amygdala was significantly increased. Eye tracking dysfunction in schizophrenia was not related to changes in the amygdala or cingulate cortex but was significantly correlated with enlargement of the lateral ventricles. Schizophrenic subjects with poor eye tracking had significantly larger lateral ventricles than controls. Eye tracking dysfunction, but not P300 abnormality, was correlated with the severity of both positive and negative symptom of schizophrenia. These findings demonstrate that psychophysiological abnormalities are associated with altered brain structure in schizophrenia.     

Diffuse axonal injury (DAI) in an autopsy case of head trauma with long survival]

The authors reported a clinico-pathological case survived 11 months after a traffic accident. A 41-year-old man had been hit by a motor car and was found in a state of semicoma. On admission, his consciousness level was III-100 to 200 (Japan Coma Scale). Pupils were isocoric; light reflex was present. Linear fracture of occipital bone was disclosed by Skull X-ray and subarachnoid hemorrhage was revealed on CT scan. This comatose state, lasting 24 hours, slowly improved and eventually he presented the so-called Korsakoff's syndrome until his death. He could not recognized his relatives, only uttered some meaningless words. He was unable to obey simple verbal orders. The patient was incontinent and right pyramidal sign was positive. On repeated CT scans, cerebral ventricles gradually increased in size; especially the enlargement of the fourth ventricle was remarkable. He expired of septic shock caused by bed sores. At autopsy brain weighed 1190 g. Old gloss contusional scars were observed on the bilateral frontal lobes including the orbital area and on the left temporal pole. Gliding contusions were revealed in the subcortical white matter beneath the left superior frontal convolution. Fibrillary gliosis was noted in this region, the deep white matter underlying the left temporal pole and the tissue surrounding the anterior horn of the left lateral ventricle. Nerve fibers were fragmented and lacerated at corpus callosum, anterior commissure and posterior limb of the left internal capsule. Bilateral pyramidal tracts showed mild myelin pallor at the brainstem. Loss of Purkinje cells were observed. This case would correspond to mile type of diffuse axonal injury proposed by Adams and Gennarelli. (ABSTRACT TRUNCATED AT 250 WORDS)     

Disturbances of cerebrospinal fluid (CSF) circulation—neuropsychiatrie symptoms and neuroradiological contribution

Summary The present study aimed at relating dementia, pseudo-neurasthenic and affective organic brain syndromes to underlying type of CSF flow disorder and to subsequent alteration of anatomy. T2*-weighted magnetic resonance imaging (MRI) in the midsagittal plane permitted an analysis of aqueductal CSF flow phenomena and hydrocephalus-induced elevation, thinning and dorsal impingement of the corpus callosum. Furthermore, the width of the third ventricle was measured on the transverse scout images. 72 patients with communicating hydrocephalus (increased aqueductal CSF pulsations) and 26 patients with aqueductal stenosis (absence of aqueductal flow phenomena) were compared with 22 controls. Dementia and affective disorders were distributed equally among both CSF flow subgroups whereas pseudo-neurasthenic syndromes were observed more frequently in non-communicating hydrocephalus (p < 0.03). Alzheimer-type and multiinfarct dementia syndromes were found more frequently in communicating hydrocephalus whereas non-classifiable dementia showed some predilection for non-communicating hydrocephalus. Callosal height, area and third ventricular width did not predict affective or pseudoneurasthenic disorder whereas third ventricular width (p < 0.01) and callosal area (p < 0.05) discriminated between demented and non-demented patients. Dorsal impingement of the corpus callosum by the falx was a non-specific finding.     

Pure alexia caused by separate lesions of the splenium and optic radiation

Pure alexia is severe difficulty in reading and understanding written language but with normal oral language and writing abilities. We report a patient with pure alexia caused by two different infarct lesions in the left lateral thalamus and the left splenium of the corpus callosum. A 56-year-old right-handed man was admitted to hospital with right homonymous hemianopia associated with pure alexia. He could write kana characters but not kanji. His cranial magnetic resonance imaging revealed two different infarct lesions in the left optic radiation and the left splenium of the corpus callosum. Magnetic resonance angiography showed mild stenosis at the origin of the right vertebral artery and stenosis of the left distal posterior cerebral artery. The mechanism of developing pure alexia can be simply explained by disconnection. We assumed that agraphia of kanji was caused by the effect of ischemia and edema following transient obstruction in branches from the distal posterior cerebral artery.     

Detection of wallerian degeneration in a newborn by diffusion magnetic resonance imaging (MRI)

We present the case of an infant with hypoxic-ischemic encephalopathy in whom wallerian degeneration is demonstrated in white-matter fiber tracts by diffusion magnetic resonance imaging (MRI). MRI was undertaken on days 2 and 9 and then at 9 months of age. On day 2, conventional MRI was normal, but diffusion MRI showed bioccipital abnormalities. On day 9, diffusion MRI showed marked abnormalities in the deep white matter of the occipital regions (left > right), corpus callosum, left posterior limb of the internal capsule, and left cerebral peduncle. Water apparent diffusion coefficient values showed a significant reduction in the left occipital white matter and corpus callosum between days 2 and 9 while demonstrating the expected pseudonormalization in cortical gray matter. Images at 9 months showed left occipital porencephaly and atrophy of the left cerebral peduncle, with the infant displaying right hemiplegia at 18 months of age. In this case, the time course of diffusion changes differed between white and gray matter, with diffusion MRI showing delayed wallerian degeneration of the cerebral white matter. This case characterizes this degeneration with clinical and follow-up MRI at 9 months of age.     

Corpus callosum atrophy as a marker of clinically meaningful cognitive decline in secondary progressive multiple sclerosis. Impact on employment status

Cognitive impairment in Multiple Sclerosis (MS) is more frequent and pronounced in secondary progressive MS (SPMS). Cognitive decline is an important predictor of employment status in patients with MS. Magnetic Resonance Imaging (MRI) markers have been used to associate tissue damage with cognitive dysfunction. The aim of the study was to designate the MRI marker that predicts cognitive decline in SPMS and explore its effect on employment status. 30 SPMS patients and 30 healthy participants underwent neuropsychological assessment using the Trail Making Test (TMT) parts A and B, semantic and phonological verbal fluency task and a computerized cognitive screening battery (Central Nervous System Vital Signs). Employment status was obtained as a quality of life measure. Brain MRI was performed in all participants. We measured total lesion volume, third ventricle width, thalamic and corpus callosum atrophy. The frequency of cognitive decline for our SPMS patients was 80%. SPMS patients differed significantly from controls in all neuropsychological measures. Corpus callosum area was correlated with cognitive flexibility, processing speed, composite memory, executive functions, psychomotor speed, reaction time and phonological verbal fluency task. Processing speed and composite memory were the most sensitive markers for predicting employment status. Corpus callosum area was the most sensitive MRI marker for memory and processing speed. Corpus callosum atrophy predicts a clinically meaningful cognitive decline, affecting employment status in our SPMS patients.