Neuropsychological consequences of childhood medulloblastoma and possible interventions: A review.

BACKGROUND: Children who have been treated for a medulloblastoma often suffer long-term cognitive impairments that often negatively affect their academic performance and quality of life. In this article, we will review the neuropsychological consequences of childhood medulloblastoma and discuss the risk factors known to influence the presence and severity of these cognitive impairments and possible interventions to improve their quality of life. METHODS: This narrative review was based on electronic searches of PubMed to identify all relevant studies. RESULTS: Although many types of cognitive impairments often emerge during a child's subsequent development, the core cognitive domains that are most often affected in children treated for a medulloblastoma are processing speed, attention and working memory. The emergence and magnitude of these deficits varies greatly among patients. They are influenced by demographic (age at diagnosis, parental education), medical and treatment-related factors (perioperative complications, including posterior fossa syndrome, radiation therapy dose, etc.), and the quality of interventions such as school adaptations provided to the child or rehabilitation programs that focus on cognitive skills, behavior and psychosocial functioning. CONCLUSION: These patients require specialized and coordinated multidisciplinary rehabilitation follow-up that provides timely and adapted assessments and culminates in personalized intervention goals being set with the patient and the family. Follow-up should be continued until referral to adult services.

Distinct visual perspective-taking strategies involve the left and right medial temporal lobe structures differently.

This study assesses the role of the human medial temporal lobe (MTL) structures in the coordination of spatial information across perspective change and, in particular, in visual perspective taking--namely the capacity to know what another individual is seeing on the visual scene. Fourteen patients with unilateral temporal lobe resection and 21 control subjects performed two tasks, called 'object location memory' and 'viewpoint recognition', respectively. In the object location memory task, subjects had to memorize the position of a target object in the environment from an initial viewpoint. They were then shown the same environment from a new viewpoint and had to indicate whether or not the target object had moved. In the viewpoint recognition task, subjects had to imagine the perspective of an avatar from the initial viewpoint and then decide whether or not the new viewpoint was that of the avatar. The results showed a double dissociation, with left MTL patients being impaired in the object location memory task but not in the viewpoint recognition task and right MTL patients being impaired in the viewpoint recognition task but not in the object location memory task. Furthermore, based on multiple regression analyses between performance and the volumes of the different MTL structures, we discuss the specific involvement of the left temporopolar cortex and of the right hippocampus in different kinds of visual perspective taking.

Autobiographical memory after temporal lobe resection: neuropsychological and MRI volumetric findings.

This study examined the contribution of medial temporal lobe (MTL) structures in autobiographical memory. While some investigators have reported a temporal gradient in memory performance, characterized by retrieval difficulties limited to recent periods of life [Squire and Alvarez (Retrograde amnesia and memory consolidation: a neurobiological perspective. Curr Opin Neurobiol 1995; 5: 169-77)], others have suggested that this impairment involves all life-time periods [Nadel and Moscovitch (Memory consolidation, retrograde amnesia and the hippocampal complex. Curr Opin Neurobiol 1997; 7: 217-27)]. In this study, autobiographical memory was assessed in 22 patients who had undergone a left (n = 12) or a right (n = 10) MTL resection for the relief of epileptic seizures and in 22 normal control participants. For this purpose, we used an autobiographical memory task (TEMPau, Piolino et al., 2003) across four time periods covering the subjects' entire lifespan. For each period, an overall autobiographical memory score (AM score) was obtained, from which a strictly episodic score (SE score), characterized by specificity and richness of details, was computed. For all events recalled, Remember responses justified by specificity of factual, spatial and temporal contents (jR responses) were measured using the Remember/Know paradigm. MRI volumetric analyses performed on the medial (i.e. hippocampus, temporopolar, entorhinal, perirhinal and parahippocampal cortices) and lateral temporal (i.e. superior, middle and inferior temporal gyri) lobe structures stated that the resection mainly included MTL structures. AM and SE scores were impaired in patients with right and left MTL resections as compared to normal controls across all time periods, reflecting the patients' particular difficulty in producing specific and detailed memories across all periods. This impairment was associated with poor autonoetic consciousness, revealed by the small number of jR responses across all periods. Results of correlation analysis between MRI volume measures of temporal lobe structures and autobiographical memory scores suggest that the right MTL structures are particularly responsive in reliving the encoding context regardless of remoteness. Our results support the bilateral MTL contribution to episodic autobiographical memory covering the entire lifespan, which is consistent with the multiple trace theory of MTL function [Moscovitch et al. (Functional neuroanatomy of remote episodic, semantic and spatial memory: a unified account based on multiple trace theory. J Anat 2005; 207: 35-66.)].

Autonoetic consciousness in autobiographical memories after medial temporal lobe resection.

This study aims to investigate autonoetic consciousness associated with episodic autobiographical memory in patients who had undergone unilateral medial temporal lobe resection for intractable epilepsy. Autonoetic consciousness, defined as the conscious feeling of mentally travelling back in time to relive a specific event, was assessed using the Remember/Know (R/K) paradigm across different time periods as proposed in the autobiographical memory task developed by Piolino et al. (TEMPau task). Results revealed that the two patient groups (left and right temporal resection) gave reduced sense of reliving (R) responses and more familiarity (K) responses than healthy controls. This poor autonoetic consciousness was highlighted when patients were asked to justify their Remember responses by recalling sensory-perceptive, affective or spatiotemporal specific details across all life periods. These results support the bilateral MTL contribution to episodic autobiographical memory covering the entire lifespan, which is consistent with the multiple trace theory of MTL function. This study also demonstrates the bilateral involvement of MTL structures in recalling specific details of personal events characterized by autonoetic consciousness.

[Investigation of the behavioural phenotype of parents of autistic children through the new FAQ self-report]. / Intérêt de l'autoquestionnaire FAQ dans le repérage d'un endophénotype chez les parents d'enfants autistes.

INTRODUCTION: Autism is characterized by impairments in communication and socialization and by the presence of circumscribed and stereotyped interest. Previous studies have shown that genetic mechanisms may enhance the vulnerability to autism. These mechanisms are complex and may involve the combination of several genes, in interaction with the environment. The genetic mechanism involved in the vulnerability to autism may also concern other disorders and some features, with enhanced prevalence in relatives of autistic patients. It has been shown, for example, that the frequency of language disorders or serial difficulties is increased in the siblings of autistic patients. Characterization and taking into account the presence of such phenotypic traits in the relations may help in understanding the results of genetic studies, in particular association studies in sibling pairs or trios. OBJECTIVE: In this study, we used a new self-report in order to identify endophenotype traits in socialization, communication, rigidity and imagination in parents of autistic children. This self-report is the French adaptation of the previous self-report created by Baron-Cohen et al., aimed at the identification of Asperger profiles in a population of students studying science. METHODOLOGY: Ten autistic children and their parents from a clinical setting were asked to participate in the study. Autistic children were characterized using the ADI-R and various psychometric tests, according to the possibilities of the child (PEP-R, WPPSI-R, WISC3). Twenty parents of normal children were recruited from three different professional settings. There were no differences between the two groups of parents in terms of age or social status. Parents of both groups were asked to fill in the FAQ self-report. RESULTS: We performed a post-hoc analysis comparing the scores of the parents in the two groups. We found a main group, but no sex effect [F (1,37)=5.46; p<0.05]. Scores of autistic parents were higher in all domains compared to the control parents (p<0.05). However, the score on the socialization subscale was the only one that significantly differed from the scores on the imagination, language and rigidity subscales [F (3,111)=20.75, p<0.001]. CONCLUSION: Our results show significant differences between the two groups of parents in the socialization domain. This is of interest both for the interpretation of the presence of allelic variants in the genetic association studies, and for the understanding of the interplay between genotype and phenotype in the development of the autistic disorder.

A volumetric MRI study of the hippocampus and the parahippocampal region after unilateral medial temporal lobe resection.

Segmentation guidelines on high-resolution MRI designed to assess remaining volumes of the hippocampus and the parahippocampal cortices after medial temporal lobe (MTL) surgery could provide a useful tool to investigate the involvement of these anatomical regions in surgical outcomes and in human memory. For this purpose, we implemented an MRI volumetric analysis, already applied to healthy population or epileptic patient before surgery, to quantify the volume of the hippocampus, the temporopolar cortex and the regions of the parahippocampal gyrus (perirhinal, entorhinal and parahippocampal cortices) spared after unilateral MTL resection carried out to treat medically uncontrolled temporal lobe epilepsy (TLE). Based on the locations of remaining anatomical landmarks, we quantified the volume of these regions in 24 patients after MTL resection and in 16 control participants. Our results show that (1) mean volumes of these regions contralateral to the epileptic focus were similar to those of normal subjects, (2) volumetric measures obtained from the resected side were much smaller than those from the non-resected side or from normal values and (3) the extent of MTL resection was comparable in right or left MTL surgery. Individual analysis of patients showed that the parahippocampal cortex, as opposed to the other regions, was not systematically removed across patients. As a post-operative MRI-based method, it therefore proves valuable to assess group data as well as to explore differences between individual patients.

Ecological assessment of the dysexecutive syndrome using execution of a cooking task.

Patients with a dysexecutive syndrome often have severe disabilities in daily life activities. The aims of this study were to use a naturalistic experimental task to assess patients' disabilities, and to study the nature of the cognitive disorders underlying them. Execution of a cooking task involving multi-tasking (Chevignard et al., 2000) was studied in 45 patients with a dysexecutive syndrome following acquired brain injury. Patients made significantly more errors and were slower than controls; more than half of the patients did not achieve the goal and demonstrated dangerous behaviours. Those results were significantly correlated to the results of the Six Elements Task and to a behavioural questionnaire. They were also correlated to brain injury severity and to patients' cooking habits. This naturalistic assessment is clinically relevant to better assess patients' dysexecutive impairments in complex activities of daily living. Correlations of the results in the cooking task with the neuropsychological assessment highlighted the role of the dysexecutive syndrome in patients' disabilities, indicating control alterations rather than planning disorders, difficulty in dealing with the environment, and inhibiting inappropriate actions. The role of attention and prospective memory was also underlined, whereas other cognitive functions did not influence task performance.