Youhei Ishii

Characteristics of exploratory eye movements in elderly people: possibility of early diagnosis of dementia

Background:  Visual cognitive dysfunction is one of the most important signs indicating the early stage of dementia. Thus, visual testing could be used as an aid to the clinical diagnosis of dementia. In the present study, exploratory eye movement was measured to evaluate visual cognitive function in elderly subjects, including those with dementia.

Developmental characteristics of visual cognitive function during childhood according to exploratory eye movements

To evaluate the development of visual cognitive function in childhood, we examined exploratory eye movements in 84 healthy subjects viewing picture-based stimuli. Age-defined groups included 4- to 6-year-olds, 7-year-olds, 10-year-olds, 14-year-olds, 16-year-olds, and adults. In each group, 7 subjects were male and 7 were female. Exploratory eye movements, recorded as gaze points using an eye-mark recorder, were analyzed in terms of the total number of gaze points (TNGP); total eye-scanning length of gaze points (TESL); total number of gaze points on the left (l TNGP) and right (r TNGP) of the screen; and responsive search score (RSS) on the left (l RSS) and right (r RSS) of the screen. Both the TESL and TNGP increased significantly with age. The TESL and TNGP of 16-year-olds and adults viewing a repeat-comparison figure were significantly greater than when viewing a comparison figure. During the repeat-comparisons, the TNGP in 4- to 6-year-olds was greater on the right than the left; the opposite was true in 16-year-olds and adults. The RSS in 4- to 10-year-olds was greater on the right than the left; 16-year-olds and adults showed the reverse findings. Thus, in the repeat-comparison task, TNGP, TESL, TNGP, and RSS differences between left and right visual fields are useful biologic markers for estimating the development of visual cognitive function.

Effects of emotionally charged sounds in schizophrenia patients using exploratory eye movements: Comparison with healthy subjects

Aims:  Emotion‐associated sounds have been suggested to exert important effects upon human personal relationships. The present study was aimed to characterize the effects of the sounds of crying or laughing on visual cognitive function in schizophrenia patients.

Impaired exploratory eye movements in children with Asperger's syndrome

OBJECTIVE Previous eye-tracking studies using an eye mark recorder have reported that disturbances in exploratory eye movements in adult schizophrenic patients are associated with social functioning. The current study sought to determine whether exploratory eye-movement disturbances are present in children with Aspergers syndrome (AS) compared with typically developing (TD) children. MATERIALS/PARTICIPANTS: The participants were 23 children with AS and 23 age-matched TD children. We measured exploratory eye movements using an EMR-8B eye mark recorder and an exploratory eye movement-measuring device. METHOD Eye movements were recorded while participants freely observed a geometric figure (free viewing task), and while they complied with the instructions of an experimenter (repeat-comparison task). We assessed eye fixation points (EFPs) and total eye scanning length (TESL) in all tasks, and measured the responsive search score (RSS) in the repeat-comparison task. RESULTS In the free viewing task, children with AS exhibited significantly shorter TESL compared with TD children. In the repeat-comparison task, children with AS exhibited significantly lower RSS. Autism Spectrum Screening Questionnaire scores were negatively correlated with both EFP and TESL, but not RSS. CONCLUSION The current results revealed that children with AS exhibited dysfunction in exploratory eye movements. Thus, assessing exploratory eye movements in a repeat-comparison task may be useful for detecting social impairment among children with AS.

Comparison of changes in the oxygenated hemoglobin level during a ‘modified rock-paper-scissors task’ between healthy subjects and patients with schizophrenia: Cognitive dysfunction in schizophrenia

The purpose of this study, using single‐event‐related near‐infrared spectroscopy (NIRS), was to examine the psychophysiological and social function assessment of 30 schizophrenic patients during a modified rock‐paper‐scissors task.

Characteristics of oxygenated hemoglobin concentration change during pleasant and unpleasant image-recall tasks in patients with depression: Comparison with healthy subjects: Emotional perception in depression

Patients with major depressive disorder (MDD) have been reported to show cognitive impairment in attention, cognition control, and motivation. The prefrontal cortex plays an important role in the pathophysiology of depression. Neurophysiological abnormalities have been examined in MDD patients by several neuroimaging studies. However, the underlying neural mechanism is still unclear. We evaluated brain function during pleasant and unpleasant image‐recall tasks using multichannel near‐infrared spectroscopy (NIRS) in MDD patients.

Comparison of changes in oxygenated hemoglobin during the tree-drawing task between patients with schizophrenia and healthy controls

Background Tree-drawing test is used as a projective psychological test that expresses the abnormal internal experience in patients with schizophrenia (SZ). Despite the widely accepted view that the cognitive function is involved in characteristic tree-drawing in patients with SZ, no study has psychophysiologically examined it. The present study aimed to investigate the involvement of cognitive function during tree-drawing in patients with SZ. For that purpose, we evaluated the brain function in patients with SZ during a tree-drawing task by using near-infrared spectroscopy (NIRS) and compared them with those in healthy controls. Patients and methods The subjects were 28 healthy controls and 28 patients with SZ. Changes in the oxygenated hemoglobin ([oxy-Hb]) concentration in both the groups during the task of drawing a tree imagined freely (free-drawing task) and the task of copying an illustration of a tree (copying task) were measured by using NIRS. Results Because of the difference between the task conditions, [oxy-Hb] levels in controls during the free-drawing task were higher than that during the copying task at the bilateral frontal pole regions and left inferior frontal region. Because of the difference between the groups, [oxy-Hb] levels at the left middle frontal region, bilateral inferior frontal regions, bilateral inferior parietal regions, and left superior temporal region during the free-drawing task in patients were lower than that in controls. Conclusion [oxy-Hb] during the tree-drawing task in patients with SZ was lower than that in healthy controls. Our results suggest that brain dysfunction in patients with SZ might be associated with their tree-drawing.

P2-28. Single-event-related changes in Oxy-Hb during verbal discrimination tasks in schizophrenic patients: Correlation with the symptom

Schizophrenic patients have been associated with cognitive dysfunction including attention and executive functions. “Shiritori” is a very popular word chain game in Japan. This game requires players to generate a word that begins with the last syllable of the preceding word. The present study assessed the difference of hemodynamic changes between schizophrenic patients and healthy controls during a Japanese word production task (shiritori) based on a single-event-related design measured by a multi-channel NIRS system. Relationships between brain activation and clinical symptoms were also examined. The subjects were 30 schizophrenic patients and 30 age- and sex-matched healthy native-Japanese speakers. Two contrasting single events (reading task as non-target stimuli, and Shiritori task as target stimuli) were randomly performed at least 20 times each. Data were calculated as a discrimination task from each averaged waveform. The patients showed significantly less activation of the prefrontal cortex than healthy subjects. In addition, there was a significant correlation between the activation value and negative symptom score as well as general psychopathological score in patients in the left front-polar region. These findings suggest that a single-event-related NIRS measurement using verbal discrimination tasks is a useful psycho-physiological index reflecting the cognitive function of schizophrenic patients.