Mutsutaka Kobayakawa

Decision making in Parkinson's disease: Analysis of behavioral and physiological patterns in the Iowa gambling task

Recent studies suggest that social recognition processes are affected by Parkinsons disease (PD). However, whether PD patients exhibit behavioral changes is still controversial. The purpose of the present study was to examine the decision making of PD patients performing the Iowa Gambling Task (IGT). We recruited a large number of early, nondemented PD patients for the IGT. We also recorded the skin conductance responses (SCRs) during the task as a measure of emotional arousal. Compared with the normal control (NC) subjects, PD patients selected more disadvantageous decks in the IGT, and their SCRs were lower than those of NC subjects before making decisions and after receiving reward or punishment. The tendency toward risky choices was not correlated with age, education, global cognitive function, or the severity of the disease. These results confirmed that the decision making of PD patients was affected by the disease, rather than by other cognitive functions; moreover, such behavior was related to lower emotional responses. Behavioral and SCR patterns of PD patients were similar to those of amygdala‐damaged patients. The response bias toward risky choices in PD may be explained by the dysfunction of the amygdala, which is known to be involved in risk evaluation.

Sensitivity to reward and punishment in Parkinson’s disease: An analysis of behavioral patterns using a modified version of the Iowa gambling task

Studies using the Iowa gambling task (IGT) have shown that patients with Parkinsons disease (PD) make disadvantageous choices characterized by immediate large rewards and delayed larger punishments. These results can be interpreted in two ways: either PD patients are hypersensitive to immediate outcomes and/or insensitive to delayed consequences or PD patients are hypersensitive to rewards and/or insensitive to punishments. In this study, we used a modified IGT in which selection of cards from the disadvantageous decks leads to immediate, small punishments and delayed, smaller rewards and selection of cards from the advantageous decks leads to immediate, large punishments and delayed larger rewards. We then compared the results obtained using this modified IGT with those obtained using the original IGT. If the PD patients were hypersensitive to the immediate outcomes of decisions, they would make disadvantageous choices in both the original and the modified IGTs. Differences between the results of the original and modified tasks would indicate impairments in balancing reward and punishment. In our analysis, PD patients selected advantageous decks and gained as much as normal subjects during the modified IGT, but they selected disadvantageous decks during the original IGT. These results indicate that the decision-making difficulties of PD patients are caused by their inability to balance reward and punishment and their hypersensitivity to reward and/or insensitivity to punishment.

Emotional impairment in Parkinson's disease.

Patients with Parkinsons disease (PD) may show emotional impairment in the early stages of the disease. PD patients show disadvantageous decision-making, which is related to decreased emotional responses, as measured by skin conductance responses (SCRs). This pattern of decreasing SCRs is similar to that observed in amygdala-damaged patients. In facial expression recognition, PD patients did not show amygdala activation. In another study, PD patients did not show amygdala activations to unpleasant olfactory stimuli, which were observed in normal controls. Emotional impairment in PD patients may reflect amygdala dysfunction in early PD.

Facial emotion recognition and cerebral white matter lesions in myotonic dystrophy type 1

In order to investigate the cognitive and neurological bases of social cognitive impairment in myotonic dystrophy type 1 (DM1), we examined the facial expression recognition abilities and the cerebral lesions in a group of DM 1 (5 men, 4 women). We measured sensitivity to facial emotions and compared the findings with magnetic resonance image (MRI) findings evaluated using a semi-quantitative method. The DM1 patients showed lower sensitivity to disgusted and angry faces as compared to the healthy controls. The assessment of brain lesions revealed that more severe lesions occurred in the frontal, temporal, and insular white matters. Sensitivity to the emotion of disgust was negatively correlated with temporal lesions, and sensitivity to anger negatively correlated with frontal, temporal, and insular lesions. The results of this study indicate an association between lesions in the frontal, temporal, and insular subcortices and decreased emotional sensitivity to disgust and anger in DM1 patients. These areas are thought to play an important role in emotional processing in the normal brain. Our results suggest that social cognitive impairment in DM1 patients is attributable to impaired emotional processing linked to white matter lesions.

Lowered sensitivity to facial emotions in myotonic dystrophy type 1.

BACKGROUND It has been observed that patients with myotonic dystrophy type 1 (DM1) exhibit social-cognitive impairment. However, the cognitive and neurological bases of the social-cognitive impairment in DM1 have not been adequately investigated. METHODS We studied cognitive deficits and impairment in facial expression recognition in two DM1 patients (one man and one woman). We measured the sensitivity of these patients to basic emotions and compared the results with those from magnetic resonance imaging and single photon emission computed tomography. RESULTS The DM1 patients showed lower sensitivity to fearful, disgusted, and angry faces than did the healthy controls. They also had lesions in the anterior temporal white matter, the amygdala, and the insular and orbitofrontal cortices. CONCLUSION The results of this study revealed that the DM1 patients had subcortical lesions in the anterior temporal areas, including the amygdala and the insular and orbitofrontal cortices. The limbic system, which includes these areas of the brain, plays an important role in emotional processing. Hence, the social-cognitive impairment in DM1 patients could be associated with a decreased sensitivity to facial expressions owing to lesions in the limbic system.

Decision-making in temporal lobe epilepsy examined with the Iowa gambling task.

Although memory, language, and executive functions have been extensively studied in patients with mesial temporal lobe epilepsy (MTLE), few investigations of the decision-making abilities of these patients have been performed. We studied implicit decision-making (decisions under ambiguity) in right and left MTLE patients using the Iowa Gambling Task. The Iowa Gambling Task is believed to detect deficits in decision-making caused by either ventromedial prefrontal cortex or amygdalo-hippocampal lesions. In the present study, MTLE patients scored poorly compared to healthy controls on this task, and right MTLE patients exhibited worse performance than left MTLE patients. Our findings indicate that the amygdalo-hippocampal complexes play important roles in decision-making. The right amygdalo-hippocampal complexes may play more important roles in implicit decision-making in particular.

Attention deficits in Japanese multiple sclerosis patients with minor brain lesion loads

Background To investigate whether Japanese multiple sclerosis (MS) patients with minor brain lesion loads have attention deficits and brain atrophy, and to correlate their circumstance. Method Twenty-one Japanese patients with relapsing-remitting MS were included in this study. Attention deficits were evaluated using Clinical Assessment for Attention (CAT) standardized according to age groups. Lesion load in the brain was assessed by tallying the total volume of plaques visible on brain magnetic resonance imaging (MRI). The width of the third ventricle and the bicaudate ratio were measured. Results The completion time for the visual cancellation tasks and/or the reaction times for the continuous performance test were prolonged in 14 patients (66.7%). The accuracy of responses was preserved throughout the CAT. Deviation from the normal value was not exaggerated based on the increasing difficulty of the task. The total volume of plaques on brain MRI was small. The width of the third ventricle was significantly increased in patients with MS when compared to controls, but was not correlated with the low performance on the CAT. Conclusions Japanese MS patients with minor brain lesion loads frequently had attention deficits characterized by slowness of automatic information processing, but controlled processing that requires working memory demands was spared.

The Montreal Cognitive Assessment and Neurobehavioral Cognitive Status Examination are useful for screening mild cognitive impairment in Japanese patients with Parkinson's disease

Diagnosis of mild cognitive impairment (MCI) in Parkinsons disease (PD; PD‐MCI) can be difficult. We examined whether the Japanese version of the Montreal Cognitive Assessment (MoCA‐J) and the Neurobehavioral Cognitive Status Examination (COGNISTAT‐J) were suitable to screen PD‐MCI.

Decision-making performance in Parkinson's disease correlates with lateral orbitofrontal volume

BACKGROUND Patients with Parkinsons disease (PD) exhibit poor decision-making, and the underlying neural correlates are unclear. We used voxel-based morphometry with Diffeomorphic Anatomical Registration through Exponentiated Lie algebra to examine this issue. METHODS The decision-making abilities of 20 patients with PD and 37 healthy controls (HCs) were measured with a computerized Iowa Gambling Task (IGT). We assessed the local gray matter volumes of the patients and HCs and their correlations with decision-making performance, disease duration, disease severity, and anti-Parkinsonism medication dose. RESULTS Compared with the HCs, the patients with PD exhibited poor IGT performances. The gray matter volumes in the medial orbitofrontal cortex, left inferior temporal cortex, and right middle frontal gyrus were decreased in the patients. Results in the regression analysis showed that lateral orbitofrontal volume correlated with performance in the IGT in PD. Regions that correlated with disease duration, severity, and medication dose did not overlap with orbitofrontal regions. CONCLUSION Our results indicate that the lateral and medial orbitofrontal cortex are related to decision-making in PD patients. Since the medial orbitofrontal cortex is shown to be involved in monitoring reward, reward monitoring seems to be impaired as a whole in PD patients. Meanwhile, the lateral region is related to evaluation of punishment, which is considered to have an influence on individual differences in decision-making performance in PD patients.

Inter- and Intra-Hemispheric Fibers of Olfactory and Motor Areas inKallmann Syndrome with Defective Corpus Callosum

Kallmann syndrome (KS) is a form of hypogonadotropic hypogonadism with variable disturbances of olfaction, with some patients having complete anosmia. In this study, we report observations of cerebral white matter connectivity in a rare patient diagnosed with KS associated with a defective corpus callosum (DCC) (KS-DCC) using non-invasive tractography-based diffusion tensor imaging (DTI). In the partial CC, two genua remnants were observed. The KS-DCC patient had a normal life without cognitive impairment and had a normal intelligence quotient, manifesting only the two common symptoms hypogonadotropic hypogonadism and anosmia. Mirror movements were not observed. Compared with normal, DTI tractography of the olfactory related area in the KS-DCC patient revealed fewer inter-hemispheric fibers between right and left olfactory areas (including olfactory tubercle and anterior commissure). Overall, the KSDCC patient had higher numbers of intra-hemispheric fibers bilaterally and fewer inter-hemispheric connecting fibers. The higher numbers of intra-hemispheric fibers connected the right thalamus and right supplementary motor area (SMA) and the left thalamus and left SMA. The fewest number of fibers observed in the KS-DCC patient were those connecting right and left SMA. The Probst bundle together with increased intra-hemispheric fibers may indicate plastic rewiring of corpus callosum connections.