Nous rapportons le cas d’un homme de 38 ans ayant présenté un épisode maniaque franc, dans les suites de l’ablation d’une tumeur kystique bénigne de l’hémisphère cérébelleux droit, compliquée d’hydrocéphalie. Cette lésion fut découverte suite à de violentes céphalées et des troubles de l’équilibre. Le tableau maniaque débuta progressivement dans la semaine suivant l’opération, alors que les suites opératoires furent simples. Un traitement associant olanzapine et divalproate améliora rapidement la symptomatologie. Si des lésions cérébelleuses ont déjà pu être décrites dans le déclenchement de troubles de l’humeur, dans notre cas, l’imagerie fonctionnelle (scintigraphie cérébrale) a suggéré l’implication de lésions frontales. Le syndrome frontal modéré a été confirmé par les tests neuropsychologiques, et par la présence à l’IRM de petites lésions en avant des ventricules latéraux, attribuées à une effusion de liquide céphalorachidien lors de l’hydrocéphalie. Au-delà de l’étiologie organique du syndrome maniaque, le cas clinique est particulièrement intéressant car le patient a présenté au décours de l’épisode maniaque un épisode dépressif majeur avec symptômes psychotiques congruents à l’humeur, alors que nous n’avons pas retrouvé d’antécédent de trouble de l’humeur.

Nous discutons ainsi différentes hypothèses :

– existence d’un trouble de l’humeur subsyndromique décompensé à la suite de la lésion, et particulièrement par le syndrome frontal ;

– déclenchement par une lésion cérébrale d’un trouble psychiatrique épisodique et alternant ;

– survenue du syndrome dépressif de manière consécutive à l’épisode maniaque, la physiopathologie de l’épisode maniaque incluant la survenue de la dépression sévère.

Ces différentes hypothèses sont discutées sur des arguments neuropsychologiques, neuroanatomiques et psychopathologiques.

Disinhibition and irritability, defined as loss of behavioral and emotional control, are frequent in the elderly. The working hypothesis for this study was that these disorders are associated with a cognitive alteration of control processes that manifests as non-routine behavior because of the dysfunction of a general executive component known as the supervisory attentional system (SAS).

Background: Inappropriate sexual behavior (ISB) is an important topic in geriatrics; etiologies remain unclear and evidence for the efficacy of treatment strategies is limited. The aims of this study were to provide a description of the phenomenology of ISB in the geriatric population, to identify potential contributing factors, and to review the efficacy of interventions aimed at reducing ISB.

Methods: A retrospective chart review was conducted of ten patients admitted to an academic inpatient geriatric psychiatry ward because of their ISB (study group) and ten patients matched in age and gender (control group). A comprehensive chart review inventory was done to determine variables that may contribute to ISB. For the study group, effectiveness, adverse effects, and discontinuation due to adverse effects of interventions aimed at reducing ISB were reviewed.

Results: A significant finding was the association of a history of right frontal lobe stroke with ISB (Fisher's Exact Probability Test p < 0.05). Also significant was performance on cognitive testing and the presence of dementia (Fisher's Exact Probability Test p < 0.05) in the study group. Citalopram was well tolerated but with minimal reduction of ISB. Atypical antipsychotics olanzapine and risperidone were effective in some cases but also had adverse effects. Medroxyprogesterone acetate was well tolerated and effective in all cases in which it was utilized (n = 5).

Conclusions: This study suggests that ISB in the geriatric population is associated with a history of right frontal lobe stroke and with severity of dementia. Case examples of pharmacologic interventions are reviewed.

This study evaluated cognitive set-shifting in 12 patients with focal lesions in the lateral prefrontal cortex (LPC) by examining their performance on the Trail Making Test from the Delis-Kaplan Executive Function System (D-KEFS). Patients with LPC lesions performed significantly worse than controls on the D-KEFS Trail Making Test on the Letter Sequencing, Number-Letter Switching (set-shifting), and Motor Speed conditions. Patients with LPC lesions performed significantly more slowly on the Number-Letter Switching condition even after controlling for performance on the four baseline conditions of the test. In addition, patients with LPC lesions exhibited significantly elevated error rates on the Number-Letter Switching condition. Results suggest that LPC lesions can lead to impaired cognitive set-shifting on a visual-motor sequencing task. (JINS, 2007, 13, 704–709.)

Response bias reflects the decision rule an individual uses when faced with uncertainty on recognition memory tasks. Recent studies indicate frontal regions may mediate response bias performance. One theory of aging also implicates frontal lobe contributions in age-related cognitive changes. This suggests that frontal lobe changes may mediate response bias in older adults. Consistent with this frontal aging hypothesis, we predicted that response bias would become more liberal with age. Methods: Participants were 181 younger (30–49) and 112 older normal adults (75+) that were part of the California Verbal Learning Test-second edition (CVLT-2) normative sample (total n = 1078). We used parametric measures of discriminability and response bias provided by the CVLT-2 scoring program. Groups were similar in IQ and education. Multi-level regression models were created to examine the effects of moderating variables. The interaction between age and age group significantly predicted response bias. Post hoc analysis indicated that increasing age was associated with more liberal bias in the older but not in the younger group. In the light of reported relationships between frontal regions and both aging and response bias, we hypothesize that frontal changes may be the underlying mechanism explaining the increase in liberal response bias with age. (JINS, 2006, 12, 1–7.)

Despite the potential impact on development, few studies have examined the influence of prefrontal lesions occurring prior to maturation of the central nervous system. This study investigates the effect of prefrontal lesions in general, as well as the impact of lesion laterality, with respect to attentional abilities. The sample comprised 36 children with prefrontal lesions and 40 healthy controls. Attentional function was assessed across four domains: selective, shifting and divided attention, and processing speed. Group mean performances for children with prefrontal lesions indicated global attentional deficits, with greatest difficulties for “higher-order” skills including shifting and divided attention. Children with left prefrontal lesions performed similarly to controls, with a specific deficit characterized by difficulties with on-line processing of auditory-verbal information. Right prefrontal lesions were primarily associated with impairments in day-to-day executive functions, including reduced monitoring, poor shifting attention and disinhibition. Children with bilateral prefrontal lesions performed worse than controls on tasks requiring greater cognitive resources. These results provide evidence of the important role played by prefrontal cortex in the development of attentional skills, and the particular role of the right prefrontal cortex. The pattern of attention deficits observed following early prefrontal lesions suggests some lateralization of function within the frontal lobes, even during childhood. (JINS, 2005, 11, 817–831.)Source of funding: Australian National Health and Medical Research Council, Australian Research Council, Murdoch Children's Research Institute.

The purpose of this study was to investigate whether inappropriate/excessive motor activity seen in children with Attention Deficit Hyperactivity Disorder (ADHD) could be characterized as Utilization Behavior (UB). Given evidence that the neuropathology of ADHD may involve frontal-striatal systems, we investigated the possibility that children with ADHD may demonstrate “utilization behavior.” Utilization Behavior (UB) is a neurobehavioral syndrome documented in individuals with damage or dysfunction in the frontal areas of the brain; patients exhibiting UB are often described as reaching out and utilizing objects in the environment in an automatic and inappropriate manner. The sample consisted of two group of children; children with ADHD (n = 32) and control children (n = 31). Children were assessed individually in a testing room where various objects, selected to elicit UB, were present. They completed cognitive tests and also were allowed to engage in an unsupervised activity. Testing sessions were videotaped and instances of physical activity (i.e., upper limb motor activity and utilization of objects) were counted by two raters. Results indicated high levels of object utilization in approximately one-half of the children with ADHD, whereas almost no such behavior was observed in controls. This behavior did not appear to be a result of generally heightened activity levels or due to instruction set, but differed according to object familiarity and object visibility. Levels of UB were statistically associated with the severity of hyperactivity, as reported by parents, of children with ADHD. This study suggests that inappropriate/excessive motor activity may, at least in part, be characterized as UB in some children with ADHD. (JINS, 2005, 11, 367–375.)

Background: Frontotemporal dementia (FTD) is difficult to diagnose in the early stages and may be misdiagnosed as Alzheimer's disease (AD) or as a psychiatric disorder. This study aimed to investigate neuropsychological function in FTD of mild severity and compare it to that of mild AD and healthy control participants.

Methods: The study comprised 11 individuals with FTD, 29 with AD and 27 healthy controls. Participants completed a comprehensive neuropsychological assessment in which each area of cognitive function was examined with several widely used clinical tests. Test scores were converted to age-corrected scaled scores and combined to form indices for six areas of cognitive function. These indices were attention, psychomotor speed, memory acquisition, memory recall, executive function and constructional ability.

Results: The FTD group performed below the level of the controls in all areas except constructional ability. FTD and AD groups showed distinct patterns of neuropsychological performance. The FTD group showed predominantly executive dysfunction with less impaired memory function, while the AD group showed the opposite pattern. The capacity of the tests to discriminate between groups was good overall, with 90% of the total sample correctly classified. Predictive success for the FTD group was 64%, given a base rate of 16%.

Conclusion: Administration of a comprehensive neuropsychological protocol including several tests of executive function allows increased certainty about accurate clinical diagnosis of mild FTD.

In a previous paper we presented a neural network called FRONTAL that attempted to capture the ability of infants to actively self-organize in a non-stationary environment. This paper describes the procedure whereby FRONTAL is interfaced to a robotic system called DART. DART comprises of a PUMA-562 arm and a real-time image processing system. The implementation procedure consisted of first connecting FRONTAL to a simulated DART robot. After successful operation, FRONTAL was connected to the real hardware DART. The ability of this robotic system to actively explore its surroundings and modify its behavior based on experience and environmental feedback confirms previous simulation results.

La desinhibición y la irritabilidad, definidas como la pérdida de control del comportamiento y la emotión, son frecuentes en los ancianos. La hipótesis de trabajo para este estudio era que estos trastornos se asocian con una alteratión cognitiva de los procesos de control que se manifiesta como un comportamiento no habitual a causa de la disfunción de un componente ejecutivo general conocido como Sistema Atentivo Supervisor (SAS). Métodos. Se seleccionó un total de 28 sujetos ancianos con deterioro cognitivo leve y se los dividió en dos grupos utilizando el Inventario Neuropsiquiátrico. Catorce sujetos se asignaron al grupo desinhibido y 14 sujetos emparejados en cuanto a la edad, el sexo y el nivel educativo formaron un grupo de control sin desinhibición. La batería neuropsicológica incluía las pruebas siguientes: Mini Examen del Estado Mental, el Test de Nombres de Boston, el Test de Fichas, el Test de Trazado y la prueba de fluidez verbal. Se diseñaron específicamente dos tareas para someter a un esfuerzo al SAS: 1) Una tarea verbal específica de ordenación de oraciones en la que los sujetos tenían que utilizar razona-miento secuencial con material verbal. Cada secuencia de prueba consístia en una serie de palabras que se mostraban en orden alterado. La construcción de algunas secuencias se tenía que hacer utilizando asociaciones habituales familiares (condiciones válidas). Por contraste, otras secuencias requerían hacer caso omiso de la selección de tales asociaciones, que eran inapropiadas dentro del contexto general de la tarea (condiciones inválidas). 2) Utilizando el test de ejecución continua, se evaluaron cuatro aspectós: atención sostenida, atención selectiva, preparatión de la atención y atención supresiva. Resultados. Las únicas dife-rencias de grupo en los resultados de las pruebas neuropsicológicas fueron las siguientes: 1) La tarea de ordenación de oraciones. En comparación con el grupo de control, el grupo desinhibido mostraba deficiencia en las condiciones inválidas y la diferencia calculada entre el número de respuestas correctas en las condiciones inválidas menos el número correspondiente en las condiciones válidas era significativamente más alto, y 2) el test de ejecución continua. Los sujetos desinhibidos tenían un número significativamente más bajo de éxitos, exclusivamente en el paradigma de “atención supresiva”. Estos resultados indican que la función del sistema supervisor de los sujetos con desinhibición está deteriorada.