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

BACKGROUND: Patients with Parkinson's 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.

[Disorders of body schema].

A variety of disorders have been associated with the concept of body schema. However, this concept has been interpreted in many ways, and there is no consensus on the nature and cognitive mechanisms of body schema. Historically, two major issues have been discussed. One was the body-specificity of the body schema, and the other was the relationship between input and output modality. Autotopagnosia, an inability to localize and orient different parts of the body, has been a focus of attention because it is thought to provide insight into the function of body schema. Although there have not been many cases of pure autotopagnosia, a double dissociation indicating the independence of body-specific system. There are a few working hypotheses for cognitive models of body schema, which can explain the different types of autotopagnosia. One model includes multiple representation subsystems for body processing, while another assumes the use of intrinsic and extrinsic egocentric coordinates to maintain on-line processing for body state. The consistency of these accounts should be examined in light of extensive neuroimaging and psychological data, to construct a plausible model for body schema.

[Neurological disease and facial recognition].

To discuss the neurological basis of facial recognition, we present our case reports of impaired recognition and a review of previous literature. First, we present a case of infarction and discuss prosopagnosia, which has had a large impact on face recognition research. From a study of patient symptoms, we assume that prosopagnosia may be caused by unilateral right occipitotemporal lesion and right cerebral dominance of facial recognition. Further, circumscribed lesion and degenerative disease may also cause progressive prosopagnosia. Apperceptive prosopagnosia is observed in patients with posterior cortical atrophy (PCA), pathologically considered as Alzheimer's disease, and associative prosopagnosia in frontotemporal lobar degeneration (FTLD). Second, we discuss face recognition as part of communication. Patients with Parkinson disease show social cognitive impairments, such as difficulty in facial expression recognition and deficits in theory of mind as detected by the reading the mind in the eyes test. Pathological and functional imaging studies indicate that social cognitive impairment in Parkinson disease is possibly related to damages in the amygdalae and surrounding limbic system. The social cognitive deficits can be observed in the early stages of Parkinson disease, and even in the prodromal stage, for example, patients with rapid eye movement (REM) sleep behavior disorder (RBD) show impairment in facial expression recognition. Further, patients with myotonic dystrophy type 1 (DM 1), which is a multisystem disease that mainly affects the muscles, show social cognitive impairment similar to that of Parkinson disease. Our previous study showed that facial expression recognition impairment of DM 1 patients is associated with lesion in the amygdalae and insulae. Our study results indicate that behaviors and personality traits in DM 1 patients, which are revealed by social cognitive impairment, are attributable to dysfunction of the limbic system.

Theory of mind impairment in adult-onset myotonic dystrophy type 1.

Patients with myotonic dystrophy type 1 (DM 1) exhibit behavioral disorders and distinctive personality traits. We hypothesize that this is due to altered social cognitive function. To investigate the cognitive basis of this impairment in DM 1 patients, we examined their theory of mind (ToM) ability, which is the specific cognitive ability to understand the mental states of others. Nine adult-onset DM 1 patients (4 men and 5 women) performed 2 ToM tasks: "Reading the Mind in the Eyes" test and faux pas recognition test. DM 1 patients were found to be impaired in both ToM tests, but had no difficulty with control tasks designed to test visual and lexical comprehension. The present results indicate that social cognitive impairment in patients with adult-onset DM 1 is associated with ToM dysfunction, which could be due to the brain lesions associated with this disease.

Impairment of odor recognition and odor-induced emotions in type 1 myotonic dystrophy.

This study aimed to test whether type 1 myotonic dystrophy (DM1) patients who have a lower sensitivity to emotional facial expressions have an abnormal olfactory threshold or recognition level. We measured DM1 patients' performances in an olfactory acuity test and respiratory responses to odor stimuli, and compared their results to those of healthy controls (HCs). We found that DM1 patients exhibited a significantly reduced odor detection sensitivity compared with that in HCs. Three out of seven DM1 patients exhibited impaired odor recognition, while other four patients had significantly lower odor recognition compared with HCs. Even when patients were able to identify the type of odor, the levels of pleasantness they reported experiencing in response to a pleasant odor were significantly lower than those reported by HCs. These subjective data in DM1 patients were reflected in the respiratory responses (RRs). In the current study, one patient showed impairments in both odor detection and odor recognition. Abnormalities of the olfactory limbic areas might have been the cause of the olfactory impairments observed in the DM1 patients.

Is "reading mind in the eyes" impaired in Parkinson's disease?

Theory of mind (ToM) is the specific cognitive ability to understand other people's mental states. Several studies have examined ToM ability in patients with Parkinson's disease (PD), using the "reading mind in the eyes" test (RMET). However, there has been no agreement as to whether or not ToM ability in this task is affected by PD. In order to obtain conclusive evidence regarding ToM ability in PD, we examined RMET-related performance in nondemented PD patients; we also used the semantic discrimination task to exclude the possibility that PD patients had difficulty in distinguishing emotional adjectives. Results indicated that ToM ability in the RMET is impaired in PD patients, and that this finding was not attributable to the visual processing of faces or the verbal comprehension of emotional adjectives. Thus, the affective aspects of ToM can be impaired in PD patients.

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.

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 Parkinson's 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.

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.

[Possible mechanism of body part as object and hand closing-in in apraxia].

We report a case of apraxia with pantomime where the patient exhibited body part as object (BPO) and hand closing-in errors as the symptoms of apraxia. The patient was a 52-year-old right-handed man who was clinically diagnosed with corticobasal degeneration. We tested the praxis ability of the patient by using 2 standard tests for apraxia: transitive gestures in response to verbal command and transitive gestures in response to visually presented objects. During the tests, the patient showed BPO errors and occasionally reached for the presented objects when he was instructed to pantomime their use without touching the objects (hand closing-in). Both BPO and hand closing-in were observed immediately after he was instructed to perform the target gestures. Hand closing-in was frequently observed when he was instructed to perform transitive gestures in response to visually presented objects. From the above results, we concluded that BPO is attributable to the inability to form precise finger postures for grasping objects, resulting in the "contamination" of the motor command by the information regarding the shape of the objects. Hand closing-in is considered to be caused by increased response to the presented object because of motor activation by perceived object images. On the whole, BPO and hand closing-in can be considered to be triggered by an overlap of objects with body images because of imprecise motor commands and increased responses to the object image.