Intrinsic functional organization of putative language networks in the brain following left cerebral hemispherectomy.

In rare cases of severe and intractable epilepsy, cerebral hemispherectomy is performed to arrest seizure activity and improve quality of life. The remaining hemisphere is often capable of supporting many cognitive functions post-surgery, although the outcome depends on the underlying etiology, hemisphere removed, and age of resection. The mechanisms underlying this massive reorganization are at present unknown.

When left-hemisphere reading is compromised: Comparing reading ability in participants after left cerebral hemispherectomy and participants with developmental dyslexia.

Objective: We investigated reading skills in individuals who have undergone left cerebral hemispherectomy and in readers with developmental dyslexia to understand diverse characteristics contributing to reading difficulty. Although dyslexia is a developmental disorder, left hemispherectomy requires that patients (re)establish the language process needed to perform the language-based tasks in the nondominant (right) hemisphere to become readers.

Methods: Participants with developmental dyslexia (DD; n = 11) and participants who had undergone left hemispherectomy (HEMI; n = 11) were matched on age and gender, and were compared on timed and untimed measures of single word and pseudo-word reading.

Complex syntax in the isolated right hemisphere: Receptive grammatical abilities after cerebral hemispherectomy.

Objectives: In this study, we explored the syntactic competence of the right hemisphere (RH) after left cerebral hemispherectomy, on the premise that it (syntactic competence) is known to be one of the most strongly left-lateralized language functions. As basic syntactic development for individuals in this subject pool has already been extensively explored, we focused instead on the investigation of complex syntactic constructions that are normally acquired later in childhood, i.e.

Literacy after cerebral hemispherectomy: Can the isolated right hemisphere read?

Objectives: Cerebral hemispherectomy, a surgical procedure undergone to control intractable seizures, is becoming a standard procedure with more cases identified and treated early in life [33]. While the effect of the dominant hemisphere resection on spoken language has been extensively researched, little is known about reading abilities in individuals after left-sided resection. Left-lateralized phonological abilities are the key components of reading, i.

Neonatal neuroimaging predicts recruitment of contralesional corticospinal tracts following perinatal brain injury.

Aim: Unilateral perinatal brain injury may result in recruitment of ipsilateral projections originating in the unaffected hemisphere and development of unilateral spastic cerebral palsy (USCP). The aim of this study was to assess the predictive value of neonatal neuroimaging following perinatal brain injury for recruitment of ipsilateral corticospinal tracts.

Method: Neonatal magnetic resonance imaging (MRI) and cranial ultrasound scans of 37 children (20 males, 17 females; median [range] gestational age 36 wks(+4) [26(+6) -42wks(+5) ] and birthweight 2312 g ([770-5230g]) with unilateral perinatal arterial ischaemic stroke (n=23) or periventricular haemorrhagic infarction (n=14) were reviewed and scored for involvement of the corticospinal trajectory.

Cerebral hemispherectomy: sensory scores before and after intensive mobility training.

Purpose: It is unclear whether sensory modalities can be modified by rehabilitation and if sensory functions vary on the affected side many years after cerebral hemispherectomy. This pilot, proof-of-concept study assessed light touch and proprioception before and after 10 days of intensive mobility training in individuals after hemispherectomy.

Methods: Light touch and proprioception of the upper and lower extremity was measured using the Fugl-Meyer sensory subtest on the paretic side in 18 individuals with hemispherectomy before and after mobility training.

Feasibility of intensive mobility training to improve gait, balance, and mobility in persons with chronic neurological conditions: a case series.

Background And Purpose: Intensive mobility training (IMT) is a rehabilitative approach aimed at improving gait, balance, and mobility through the incorporation of task-specific, massed practice. The purpose of this case series was to examine the feasibility and benefits of the IMT protocol across a sample of 4 individuals with diverse chronic neurological diagnoses, including incomplete spinal cord injury, Parkinson's disease, stroke, and cerebral hemispherectomy.

Methods: The 4 participants enrolled in the IMT protocol and followed an intensive treatment schedule of 3 h/d sessions for 10 consecutive weekdays totaling 30 hours.

Cortical reorganisation in a preterm born child with unilateral watershed infarction.

In this case report we describe the presence of a unilateral watershed infarction in a preterm born infant. Structural imaging in the neonatal period and in adolescence confirmed a typical lesion pattern compatible with watershed infarction in term born infants. Though the resulting parasagittal cleft transected the primary motor cortex, motor function of the affected hand was relatively spared.

Constraint-induced movement therapy for individuals after cerebral hemispherectomy: a case series.

Background And Purpose: This case report describes the feasibility and efficacy of the use of constraint-induced movement therapy (CIMT) in 4 individuals (aged 12-22 years) who underwent cerebral hemispherectomy (age at time of surgery=4-10 years). The aims of this case series were: (1) to evaluate the feasibility of this therapeutic approach involving a shortened version of CIMT, (2) to examine improvements that occurred within the upper extremity of the hemiparetic side, (3) to investigate the feasibility of conducting brain imaging in individuals with depressed mental ages, and (4) to examine changes in the sensorimotor cortex following intervention.

Case Description: The patients received a shortened version of CIMT for 3 hours each day for a period of 10 days.

Asymmetry of temporal processing in listeners with normal hearing and unilaterally deaf subjects.

Objectives: In general, auditory cortex on the left side of the brain is specialized for processing of acoustic stimuli with complex temporal structure including speech, and the right hemisphere is primary for spectral processing and favors tonal stimuli and music. This asymmetry in processing is further emphasized when hemisphere-favored stimuli are presented to the contralateral ear. The purpose of the first experiment is to further investigate the properties that dictate lateralized processing of auditory stimuli by ear and the relationship between auditory task and stimulus type.

Dichotic listening after cerebral hemispherectomy: methodological and theoretical observations.

We examined two commonly used dichotic listening tests for measuring the degree of hemispheric specialization for language in individuals who had undergone cerebral hemispherectomy: the consonant-vowel (CV) nonsense syllables and the fused words (FW) tests, using the common laterality indices f and lambda. Hemispherectomy on either side resulted in a massive contralateral ear advantage, demonstrating nearly complete ipsilateral suppression of the left ear in the right hemispherectomy group but slightly less complete suppression of the right ear in the left hemispherectomy group. The results are consistent with the anatomical model of the ear advantage [Kimura, D.

Locomotor training remodels fMRI sensorimotor cortical activations in children after cerebral hemispherectomy.

Purpose: This study examined whether locomotor training, which included body weight-supported treadmill therapy, improved walking and induced cortical representational adaptations using functional magnetic resonance imaging in the remaining sensorimotor network after cerebral hemispherectomy.

Methods: Hemispherectomy patients (n = 12) underwent 2 weeks of gait training for at least 30 hours each. They were tested pre- and posttraining with the Fugl-Meyer Motor Assessment, unassisted single-limb stance time, and usual and fastest walking speeds.

Residual motor control and cortical representations of function following hemispherectomy: effects of etiology.

Fifteen posthemispherectomy children were examined to assess residual motor function of the paretic side using the 74-point Fugl-Meyer Assessment of Motor Recovery scale. The degree of residual motor control differed for upper and lower extremities, with hand function being most severely impaired. Posthemispherectomy motor outcomes also differed as a function of etiology: cortical dysplasia, perinatal infarct, and Rasmussen's encephalitis.

Modulations of 'late' event-related brain potentials in humans by dynamic audiovisual speech stimuli.

Lipreading reliably improve speech perception during face-to-face conversation. Within the range of good dubbing, however, adults tolerate some audiovisual (AV) discrepancies and lipreading, then, can give rise to confusion. We used event-related brain potentials (ERPs) to study the perceptual strategies governing the intermodal processing of dynamic and bimodal speech stimuli, either congruently dubbed or not.

How normal is grammatical development in the right hemisphere following hemispherectomy? The root infinitive stage and beyond.

We examined the morphosyntax of eight left hemispherectomized children at two different stages and compared it to MLU-matched normals. We found that the language of the hemispherectomies paralleled that of their MLU matches with respect to the specific morphosyntactic characteristics of each stage. Our findings provide strong evidence for the presence of functional categories in all early grammars and demonstrate that grammatical development, regardless of its neural substrate, is highly constrained by UG and follows a narrowly determined course.

Evidence of a visual-to-auditory cross-modal sensory gating phenomenon as reflected by the human P50 event-related brain potential modulation.

We investigated the existence of a cross-modal sensory gating reflected by the modulation of an early electrophysiological index, the P50 component. We analyzed event-related brain potentials elicited by audiovisual speech stimuli manipulated along two dimensions: congruency and discriminability. The results showed that the P50 was attenuated when visual and auditory speech information were redundant (i.