Reward modality modulates striatal responses to reward anticipation in ADHD: Effects of affiliative and food stimuli.

Altered reward sensitivity has been proposed to underlie symptoms of attention deficit hyperactivity disorder (ADHD). Functional magnetic resonance imaging (fMRI) studies have reported hypoactivation to reward-predicting cues in the ventral striatum among individuals with ADHD, using experimental designs with and without behavioral response requirements. These studies have typically used monetary incentives as rewards; however, it is unclear if these findings extend to other reward types. The current study examined striatal responses to anticipation and delivery of both affiliative and food reward images using a classical conditioning paradigm. Data from 20 typically developing young adults, and 20 individuals diagnosed with ADHD were included in a region-of-interest analysis for a priori striatal regions. Consistent with findings from studies using monetary rewards, individuals with ADHD showed decreased activation to cues predicting affiliative rewards in the bilateral ventral and dorsal striatum and increased activation to the delivery of affiliative rewards in the ventral striatum. No group differences were found in striatal responses to food reward cues or images. These results suggest hyposensitivity to reward-predicting cues in ADHD extends to affiliative rewards, with important implications for understanding and managing the learning and social functioning of those with ADHD.

Applicability of an immersive virtual reality system for assessing route learning in older adults.

Spatial orientation is defined as the ability to find one's way around an environment, follow familiar routes, recognize places, and learn new routes. Spatial disorientation is one of the early symptoms of Alzheimer's disease (AD), and traditional cognitive evaluation lacks ecological validity. Therefore, new assessment methods are needed for the early identification of this cognitive impairment. Objective: This study aimed to compare the applicability and stability of an immersive virtual reality (VR) system developed to assess route learning between older adults with and without mild cognitive impairment (MCI). Methods: The study sample included 43 older adults: 22 without MCI and 23 with MCI. Applicability was assessed based on the recording of adverse events and the sense of presence reported through questionnaires. The Mann-Whitney U test was applied to compare the applicability of the Spatial Orientation in Immersive Virtual Environment Test (SOIVET)-Route task between older adults with and without MCI. Both short- and long-term stabilities of the task were evaluated using the intraclass correlation coefficient (ICC). Results: The mean age of participants was 71.4 years (SD=5.5). A minimum number of adverse events (mean=1.46; SD=2.11) and high levels of presence (mean=138.04; SD=14.80) were reported, and there was no difference between groups with and without MCI. A good to excellent correlation was found for short-term stability (CCI 0.78) and a reasonable correlation was found for long-term stability (CCI 0.58). Conclusions: The VR system was applicable for older adults and showed a good to excellent correlation for short-term stability.

Orientação espacial é a capacidade de encontrar um caminho em um ambiente, seguir rotas familiares, reconhecer lugares e aprender novas rotas. A desorientação espacial é um dos primeiros sintomas da doença de Alzheimer, e a avaliação cognitiva tradicional carece de validade ecológica. Diante disso, novos métodos de avaliação são necessários para a identificação precoce desse comprometimento cognitivo. Objetivo: Este estudo teve como objetivo comparar a aplicabilidade e a estabilidade de um sistema de realidade virtual imersivo desenvolvido para avaliar a aprendizagem de rotas entre idosos com e sem comprometimento cognitivo leve (CCL). Métodos: Participaram do estudo 43 idosos: 22 sem CCL e 23 com CCL. A aplicabilidade foi avaliada por meio do registro de eventos adversos e pela sensação de presença relatados. O teste de Mann-Whitney foi aplicado para comparar a aplicabilidade da tarefa SOIVET-Route entre idosos com e sem CCL. A estabilidade da tarefa em curto e longo prazo foi avaliada pelo coeficiente de correlação intraclasse (ICC). Resultados: A idade média dos participantes foi de 71,4 anos (desvio padrão ­ DP=5,5). Em relação à aplicabilidade, encontramos mínimo relato de sintomas adversos (média=1,46; DP=2,11) e altos níveis de sensação de presença (média 138,04; DP=14,80), e não houve diferença entre os grupos com e sem CCL. Ao analisarmos a estabilidade, encontramos de boa a excelente correlação em curto prazo (CCI=0,78) e uma correlação razoável em longo prazo (CCI=0,58). Conclusões: O sistema de realidade virtual foi aplicável em idosos e mostrou boa correlação na estabilidade de curto prazo.

Two Immersive Virtual Reality Tasks for the Assessment of Spatial Orientation in Older Adults with and Without Cognitive Impairment: Concurrent Validity, Group Comparison, and Accuracy Results.

OBJECTIVE: Spatial disorientation is common in Alzheimer's disease (AD), Mild Cognitive Impairment (MCI), and preclinical individuals with AD biomarkers. However, traditional neuropsychological tests lack ecological validity for the assessment of spatial orientation and to date, there is still no gold standard. The current study aimed to determine the validity and accuracy of two virtual reality tasks for the assessment of spatial orientation. METHODS: We adapted two spatial orientation tasks to immersive virtual environments: a "survey to route" task in which participants had to transfer information from a map to their body position within a maze [Spatial Orientation in Immersive Virtual Environment Test (SOIVET) Maze], and an allocentric-type, route learning task, with well-established topographic landmarks (SOIVET Route). A total of 19 MCI patients and 29 cognitively healthy older adults aged 61-92 participated in this study. Regular neuropsychological assessments were used for correlation analysis and participant performances were compared between groups. Receiver Operating Characteristic (ROC) curve analysis was performed for accuracy. RESULTS: The SOIVET Maze correlated with measures of visuoperception, mental rotation, and planning, and was not related to age, educational level, or technology use profile. The SOIVET Route immediate correlated with measures of mental rotation, memory, and visuoconstruction, and was influenced only by education. Both tasks significantly differentiated MCI and control groups, and demonstrated moderate accuracy for the MCI diagnosis. CONCLUSION: Traditional neuropsychological assessment presents limitations and immersive environments allow for the reproduction of complex cognitive processes. The two immersive virtual reality tasks are valid tools for the assessment of spatial orientation and should be considered for cognitive assessments of older adults.

An Adaptation of Pavlovian-to-Instrumental Transfer (PIT) Methodology to Examine the Energizing Effects of Reward-Predicting Cues on Behavior in Young Adults.

There is growing recognition that much of human behavior is governed by the presence of classically conditioned cues. The Pavlovian-to-Instrumental Transfer (PIT) paradigm offers a way to measure the effects of classically conditioned stimuli on behavior. In the current study, a novel behavioral task, an adaptation of the PIT framework, was developed for use in conjunction with an fMRI classical conditioning task. Twenty-four healthy young adults completed (1) instrumental training, (2) Pavlovian conditioning, and (3) a Transfer test. During instrumental training, participants learned to apply force to a handgrip to win money from slot machines pictured on a computer screen. During Pavlovian conditioning, slot machines appeared with one of two abstract symbols (cues), one symbol was predictive of monetary reward. During the Transfer test, participants again applied force to a handgrip to win money. This time, the slot machines were presented with the Pavlovian cues, but with the outcomes hidden. The results indicated increased effort on the instrumental task, i.e. higher response frequency and greater force, in the presence of the reward-predicting cue. Our findings add to the growing number of studies demonstrating PIT effects in humans. This new paradigm is effective in measuring the effects of a conditioned stimulus on behavioral activation.

Methylphenidate modifies reward cue responses in adults with ADHD: An fMRI study.

Attention deficit hyperactivity disorder (ADHD) has been associated with neural hyposensitivity to reward-predicting cues. Methylphenidate is widely used in the management of the disorder's symptoms, but its effects on reward sensitivity in ADHD are unknown. The current study used fMRI to measure striatal responses to reward-predicting cues in adults with ADHD on and off methylphenidate and a control group, during a classical conditioning task. Responses to cued reward were also explored. Larger differences in the ventral striatum activation to reward cues versus non-reward cues were observed when the ADHD participants were on methylphenidate compared to placebo. In response to cued-reward outcome, an exploratory analysis showed methylphenidate reduced the BOLD time-series correlation between the dorsal striatum and dorsal medial prefrontal cortex. Methylphenidate's therapeutic effects may be mediated by altering reward processing in individuals with ADHD.

Behavioral adjustment to asymmetric reward availability among children with and without ADHD: effects of past and current reinforcement contingencies.

Altered reinforcement sensitivity is hypothesized to underlie symptoms of attention deficit hyperactivity disorder (ADHD). Here we evaluate the behavioral sensitivity of Brazilian children with and without ADHD to a change in reward availability. Forty typically developing children and 32 diagnosed with DSM-IV ADHD completed a signal-detection task in which correct discriminations between two stimuli were associated with different frequencies of reinforcement. The response alternative associated with the higher rate of reinforcement switched, without warning, after 30 rewards were delivered. The task continued until another 30 rewards were delivered. Both groups of children developed a response bias toward the initially more frequently reinforced alternative. This effect was larger in the control group. The response allocation of the two groups changed following the shift in reward availability. Over time the ADHD group developed a significant response bias toward the now more frequently reinforced alternative. In contrast, the bias of the control group stayed near zero after an initial decline following the contingency change. The overall shift in bias was similar for the two groups. The behavior of both groups of children was sensitive to the asymmetric reward distribution and to the change in reward availability. Subtle group differences in response patterns emerged, possibly reflecting differences in the time frame of reward effects and sensitivity to reward exposure.

Two new virtual reality tasks for the assessment of spatial orientation Preliminary results of tolerability, sense of presence and usability.

Spatial orientation is a cognitive domain frequently impaired in Alzheimer's Disease and can be one of its earliest symptoms. OBJECTIVE: This paper describes the results of tolerability, sense of presence and usability of two immersive virtual reality tasks for the assessment of spatial orientation, using VR headset in adults. METHODS: 31 healthy adults recruited from university and the local community performed two experimental immersive virtual reality tasks of spatial orientation: the SOIVET-Maze for the assessment of allocentric to egocentric spatial abilities and the SOIVET-Route for the assessment of spatial memory and landmark recognition. Participants completed questionnaires about sense of presence, cybersickness symptoms, technology use profile and motion sickness history. Usability measures were assessed by spontaneous feedback from participants. RESULTS: All participants were able to understand the task instructions and how to interact with the system. Both tasks seemed to induce a strong sense of presence, as assessed by the Witmer and Singer Presence Questionnaires (M=128 and 143 for SOIVET-Maze and SOIVET-Route, respectively). The SOIVET-Route had a small numeric advantage over the SOIVET-Maze tolerability scores assessed by the Cybersickness Questionnaire (M=4.19, SD=5.576 and M=3.52, SD=6.418 for SOIVET-Maze and SOIVET-Route respectively). Also, there were no drop-outs on the SOIVET-Route due to tolerability issues, unlike the SOIVET-Maze, which had two drop-outs. However, this difference was not statistically significant (Z= -.901, p= 0.368, Wilcoxon signed-rank test).

A orientação espacial é um domínio cognitivo freqüentemente comprometido na doença de Alzheimer e pode ser um dos primeiros sintomas manifestados. OBJETIVO: Este artigo descreve os resultados de tolerabilidade, sensação de presença e usabilidade de duas tarefas imersivas de realidade virtual para avaliação da orientação espacial, utilizando óculos de RV em adultos. MÉTODOS: 31 adultos saudáveis, ​​recrutados entre estudantes universitários e da comunidade local, realizaram duas tarefas de realidade virtual imersiva para avaliação da orientação espacial: A tarefa SOIVET-Maze para avaliação da capacidade de transposição da orientação alocêntrica para egocêntrica e a tarefa SOIVET-Route para avaliação da memória espacial e reconhecimento de pontos de referência. Os participantes também responderam questionários sobre Sensação de Presença, Sintomas de cybersickness, Perfil de Uso de Tecnologia e Histórico de cinetose. Feedback espontâneo dos participantes foi utilizado como medida de usabilidade. RESULTADOS: Todos os participantes conseguiram compreender as instruções da tarefa e como interagir com o sistema. Ambas tarefas parecem induzir forte sensação de presença, avaliada pelo Questionário de Presença de Witmer e Singer (M=128 e 143 para SOIVET-Maze e SOIVET-Route, respectivamente). A tarefa SOIVET-Route teve uma pequena vantagem numérica em relação à tarefa SOIVET-Maze na pontuação de tolerabilidade avaliada pelo Questionário de Cybersickness (M=4,19, SD=5,576 e M=3,52, SD=6,418 para SOIVET-Maze e SOIVET-Route respectivamente). Além disso, não houve desistências na SOIVET-Route devido a problemas de tolerabilidade, ao contrário da SOIVET-Maze, que teve dois drop-outs. No entanto, essa diferença não foi estatisticamente significativa (Z= -901, p=0,368, teste de postos sinalizados de Wilcoxon).

All that glitters is not gold: When motor and vocal tics in a child do not match Tourette syndrome: A case report.

The atypical form of Pantothenate Kinase-Associated Neurodegeneration (PKAN) tends to present at around the age of 14 years, has a heterogeneous presentation with extrapyramidal symptoms, and approximately one third of patients exhibit psychiatric problems. This paper reports the case of a patient with apparent typical symptoms of Tourette syndrome. However, the severity and poor response to treatment led to further investigation and the diagnosis of PKAN as a secondary cause of Tourettism was reached.

A forma atípica de PKAN costuma se apresentar por volta dos 14 anos de idade, possui uma sintomatologia heterogênea, com sintomas extrapiramidais e, em cerca de um terço dos pacientes, também com a manifestação de sintomas psiquiátricos. O presente artigo relata o caso de uma paciente com sintomatologia típica da Síndrome de Tourette à primeira vista. Entretanto, a gravidade do quadro e pouca resposta ao tratamento levaram a uma maior investigação e ao diagnóstico de PKAN como causa secundária do Tourettismo.

Dissociation of depression from apathy in traumatic brain injury: a case report.

Although not evident clinically, lesions to the prefrontal cortex cause great social and functional impairment to patients. The anterior cingulate cortex is intimately involved with motivational behavior and after injury to this area the onset of an apathetic state can be observed. This paper describes the case of a patient with traumatic brain injury to the prefrontal lobe presenting with a depressive syndrome associated with apathetic symptoms. After appropriate treatment for depression, intense apathy was revealed, an irreversible sequelae of the traumatic brain injury, constituting the main barrier to the patient's return of lifestyle and independence.

Apesar de não se destacarem ao olhar clínico, as lesões do córtex pré-frontal acarretam grande prejuízo funcional e social aos pacientes. O córtex do cíngulo anterior está intimamente envolvido com o comportamento motivacional e o que se observa após um dano a esta região é a instalação de um estado apático. Este trabalho visa relatar o caso de um paciente com lesão traumática do lobo pré-frontal que apresentou uma síndrome depressiva associada a sintomas apáticos. Após tratamento adequado da depressão foi possível perceber intensa apatia, sequela irreversível do traumatismo crânio encefálico, que se constituiu como principal obstáculo ao retorno do estilo de vida e independência do paciente.