Verbal Memory Abilities of Children With Brain Tumors

Several critical neuroanatomical structures and pathways for memory performance are located in the third ventricle region. This led us to predict that verbal memory abilities would be more impaired in children treated for third ventricle tumors compared to those treated for cerebellar tumors. Archival data was obtained from 24 pediatric patients with third ventricle region tumors and 18 pediatric patients with cerebellar tumors. Neuroradiological verifications of tumor involvement and hydrocephalus severity (i.e., Evans Index) on preoperative scans and MRIs proximal to the time of the neuropsychological evaluation were conducted. The potential confounds of hydrocephalus severity, seizure medication, age, radiation treatment, and chemotherapy were addressed. Verbal IQ was comparable between tumor groups and in the Average range. The third ventricle region group performed significantly worse on list learning and delayed list recall compared to the cerebellar group. Their mean performance was in the clinically impaired range on both trials. The third ventricle region tumor group performed better than the cerebellar tumor group on Digit Span, a basic repetition, attention span task. These findings support the hypothesis that pediatric patients with third ventricle region brain tumors are more likely to be impaired on verbal recall tasks compared to pediatric patients with cerebellar brain tumors. In contrast, patients who were treated for cerebellar tumors were more impaired on the basic repetition, attention span task compared to patients who were treated for third ventricle tumors. Future studies should examine the specific neuroanatomical structures and pathways that are damaged and may influence differential cognitive impairments in children.     

Uneven Profiles: Language Minority Learners' Word Reading, Vocabulary, and Reading Comprehension Skills

English reading comprehension skill development was examined in a group of 87 native Spanish-speakers developing English literacy skills, followed from fourth through fifth grade. Specifically, the effects of Spanish (L1) and English (L2) oral language and word reading skills on reading comprehension were investigated. The participants showed average word reading skills and below average comprehension skills, influenced by low oral language skills. Structural equation modeling confirmed that L2 oral language skills had a large, significant effect on L2 reading comprehension, whereas students' word-level reading skills, whether in L1 or L2, were not significantly related to English reading comprehension in three of four models fitted. The results converge with findings from studies with monolinguals demonstrating the influence of oral language on reading comprehension outcomes, and extend these findings by showing that, for language minority learners, L2 oral language exerts a stronger influence than word reading in models of L2 reading.     

The Role of Cortico-Thalamo-Cortical Circuits in Language: Recurrent Circuits Revisited

Neuropsychology Review - Based on a review of recent literature, a recurrent circuit model describes how cortico-thalamo-cortical and cortico-cortical circuitry supports word retrieval,...     

A case of thalamic aphasia with postmortem verification

This study discusses a case of aphasia after dominant thalamic lesion, a hemorrhagic infarction. Unlike other such cases, both repeated standardized assessment and postmortem verification were available. The patient was assessed at 3 weeks and again at 9 weeks postonset. The aphasia demonstrated the syndrome common to dominant thalamic hemorrhage: fluent but paraphasic output sometimes deteriorating to jargon, comprehension less impaired than this type of output usually indicates, and the least impairment in repetition. As sometimes reported in previous cases, semantic paraphasias were more common than phonemic paraphasias. The lesion was located in the dorsal aspect of the lateral nucleus, but it extended into the pulvinar, including the anterior superior lateral aspect which has been implicated in language by previous studies. Thus, data from this case are consistent with an involvement of the dominant pulvinar in language and suggest that this role involves the semantic aspects of language.     

Verbal memory abilities of children with brain tumors.

Several critical neuroanatomical structures and pathways for memory performance are located in the third ventricle region. This led us to predict that verbal memory abilities would be more impaired in children treated for third ventricle tumors compared to those treated for cerebellar tumors. Archival data was obtained from 24 pediatric patients with third ventricle region tumors and 18 pediatric patients with cerebellar tumors. Neuroradiological verifications of tumor involvement and hydrocephalus severity (i.e., Evans Index) on preoperative scans and MRIs proximal to the time of the neuropsychological evaluation were conducted. The potential confounds of hydrocephalus severity, seizure medication, age, radiation treatment, and chemotherapy were addressed. Verbal IQ was comparable between tumor groups and in the Average range. The third ventricle region group performed significantly worse on list learning and delayed list recall compared to the cerebellar group. Their mean performance was in the clinically impaired range on both trials. The third ventricle region tumor group performed better than the cerebellar tumor group on Digit Span, a basic repetition, attention span task. These findings support the hypothesis that pediatric patients with third ventricle region brain tumors are more likely to be impaired on verbal recall tasks compared to pediatric patients with cerebellar brain tumors. In contrast, patients who were treated for cerebellar tumors were more impaired on the basic repetition, attention span task compared to patients who were treated for third ventricle tumors. Future studies should examine the specific neuroanatomical structures and pathways that are damaged and may influence differential cognitive impairments in children.     

Functional MRI of Language in Aphasia: A Review of the Literature and the Methodological Challenges

Animal analogue studies show that damaged adult brains reorganize to accommodate compromised functions. In the human arena, functional magnetic resonance imaging (fMRI) and other functional neuroimaging techniques have been used to study reorganization of language substrates in aphasia. The resulting controversy regarding whether the right or the left hemisphere supports language recovery and treatment progress must be reframed. A more appropriate question is when left-hemisphere mechanisms and when right-hemisphere mechanisms support recovery of language functions. Small lesions generally lead to good recoveries supported by left-hemisphere mechanisms. However, when too much language eloquent cortex is damaged, right-hemisphere structures may provide the better substrate for recovery of language. Some studies suggest that recovery is particularly supported by homologues of damaged left-hemisphere structures. Evidence also suggests that under some circumstances, activity in both the left and right hemispheres can interfere with recovery of function. Further research will be needed to address these issues. However, daunting methodological problems must be managed to maximize the yield of future fMRI research in aphasia, especially in the area of language production. In this review, we cover six challenges for imaging language functions in aphasia with fMRI, with an emphasis on language production: (1) selection of a baseline task, (2) structure of language production trials, (3) mitigation of motion-related artifacts, (4) the use of stimulus onset versus response onset in fMRI analyses, (5) use of trials with correct responses and errors in analyses, and (6) reliability and stability of fMRI images across sessions. However, this list of methodological challenges is not exhaustive. Once methodology is advanced, knowledge from conceptually driven fMRI studies can be used to develop theoretically driven, mechanism-based treatments that will result in more effective therapy and to identify the best patient candidates for specific treatments. While the promise of fMRI in the study of aphasia is great, there is much work to be done before this technique will be a useful clinical tool.     

Subcortical Functions in Cognition

Neuropsychology Review -