Yoshihiro Itaguchi

• Ph.,D.
• Professor (Associate) at Keio University

Verbal fluency (VF) represents an important aspect of intelligence, in which oral word generation is demanded following semantic or phonemic cues. Two reliable phenomena of VF execution have been reported: A decay in performance across 1-minute trial and a discrepancy score between the semantic and phonemic VF tests (VFTs). Although, these characte...

This study investigated the effects of the time interval between virtual reality (VR) sessions on visually induced motion sickness (VIMS) reduction to better understand adaptation to and recovery from a nauseating VR experience. The participants experienced two 6-min VR sessions of a first-person motorcycle ride through a head-mounted display with...

In robot-assisted rehabilitation, it is unclear which type of haptic guidance is effective for regaining motor function because of the lack of direct comparisons among multiple types of haptic guidance. The objective of this study was to investigate the effects of different types of haptic guidance on upper limb motor learning in a spiral drawing t...

The present study aimed to investigate whether the laws of isochrony and homothety hold for Japanese characters by measuring handwriting movements using a liquid crystal display tablet. The law of isochrony means that handwriting time is constant regardless of handwriting size. The law of homothety means that the time required for each character is...

サマリー1.体性感覚は，複雑な身体状態を素早く中枢に供給するため，正確な運動の実現には欠かせない．2.体性感覚障害によって生じる運動行為の拙劣さや特徴的な運動プロファイルは，運動器の障害によって生じるものとは区別可能である．3.道具の身体化は，身体と同じような方法で外的物体が扱われる情報処理であると定義できる．この定義は，体性感覚障害が生じた“身体”に対して，これまでにない新たな視点を提供する．

Robots are used by humans not only as tools but also to interactively assist and cooperate with humans, thereby forming physical human–robot interactions. In these interactions, there is a risk that a feedback loop causes unstable force interaction, in which force escalation exposes a human to danger. Previous studies have analyzed the stability of...

Robots are used by humans not only as tools but also to interactively assist and cooperate with humans, thereby forming physical human-robot interactions. In these interactions, there is a risk that a feedback loop causes unstable force interaction, in which force escalation exposes a human to danger. Previous studies have analyzed the stability of...

Usually, our bodily movements are performed against gravity. Most studies using a force field have focused on adaptation processes to force applied in the horizontal plane, which is novel to us, but not to force in the gravitational direction. The present study investigated the immediate effects (aftereffects) of a force toward the gravitational di...

Semantic verbal fluency (VF), assessed by animal category, is a task widely used for early detection of dementia. A feature not regularly assessed is the occurrence of errors such as perseverations and intrusions. So far, no investigation has analyzed the how and when of error occurrence during semantic VF in aging populations, together with their...

The present study investigated the performance of verbal fluency tests conducted repeatedly (5 times in a week×4 or 5 weeks) by two stroke patients with a decline of frontal lobe functions, in terms of time and word frequency information. In both patients, the numbers of total responses increased, while they remained constant in the later evaluatio...

本研究は，日常的に利用できるタブレットから取得できる情報を用いて，書字運動および書字障害を定量的に評価する手法を提案することを目的とした。頭頂葉を含む病変を有する症例 5 名（以下，患者群）と高齢健常者 5 名（以下，統制群）が参加した。提案手法によって，（1）書字障害を呈する症例のみにおいて，字画間にかかる時間が長かったこと，（2）症状にかかわらず，患者群の速度極小点の数が統制群の範囲を越えて大きかったこと，（3）複数症例で，字画間の時間と距離の関係が統制群と異なっていたこと，（4）統制群の字画間の時間と距離の相関係数は，比較的安定であったことが明らかとなった。この知見に基づき，タブレットによる書字運動評価の有用性について議論した。

While studies have increasingly used virtual hands and objects in virtual environments to investigate various processes of psychological phenomena, conflicting findings have been reported even at the most basic level of perception and action. To reconcile this situation, the present study aimed 1) to assess biases in size perception of a virtual ha...

Through cognitive task performance, we examined the functional role of finger writing (kūsho) in a Japanese patient with moderate sensory aphasia and reading difficulties. We hypothesized that the visual feedback of kūsho would improve visual language processing, which we tested with a “kanji construction task” using character subparts. Results sho...

English translation

Driving simulator usage is often accompanied by motion sickness, and techniques for its prevention are not yet established. To reduce visually induced motion sickness (VIMS), we investigated the effects of synchronised presentation of engine sounds and motorcycle vibration on VIMS. A total of 80 participants experienced a driving scene with a head-...

Studies have suggested that the proficiency of an end effector is the primary factor that defines kinematics of reach-to-grasp movements across the types of effectors, such as the hand or a tool. In particular, the duration of the plateau, or the time of static open aperture (i.e., the distance between tips of effectors) is typically longer for too...

The present study proposed a quantitative way to assess writing action and writing disorder using a tablet device. The proposed method revealed that (a) inter-stroke time interval was longer in patients with writing disorder, (b) the number of local minima in the tangential velocity was larger in the patients regardless of their symptoms, (c) sever...

Kūsho, which refers to a behavior in which one moves the index finger as a substitute for a pen in the air or on a surface, mostly used when trying to recall the shape of a written character or the spelling of a word, has been known to facilitate cognitive task performance among kanji writing-system users. This study investigates whether the facili...

統計学的手法は多くの学問分野で，研究の主張における信頼性の一部を担保するために用いられる。しかしながら，統計学的手法の誤用や濫用の問題も少なからず指摘されている。神経心理学において，臨床検査を誤った方法で運用してはいけないように，統計手法もルールに則った適切な運用が求められる。そこで本稿では，統計的仮説検定の基礎およびその使用において考慮すべき検定の多重性，効果量，検出力について解説した上で，神経心理学研究における統計手法の運用状況を概観する。さらに，それらに関わる問題の実用的な対策についていくつか提案する。

A position reproduction task was performed, in a controlled experimental environment, by seven patients with a parietal lobe lesion. We obtained mainly three findings: (a) even for patients who failed a thumb localization test, the accuracy of position reproduction was adequate and did not deviate from the range of error observed in healthy young p...

本研究では，2000年～2016年までの17年間に神経心理学誌に掲載された170編の原著論文におけるデータ解析方法の運用状況を調べ，さらに統計的仮説検定における多重性問題および検出力（検定力）の問題を検討した。検討の結果，多くの研究で多重性問題は意識されておらず，特に相関係数を算出する研究において，検定の多重性問題が統制されていないことが明らかとなった。検出力の問題に関しては，サンプル数が多いために検出力が高すぎるケース，およびサンプル数の少なさのため検出力が低くなっているケースの両方を確認した。これらの問題に対して，理論的観点と，“神経心理学”誌における現状の両面から解決方法を提案した。

The amount of practice and time interval between practice sessions are important factors that influence motor learning efficiency. Here, we aimed to reveal the relationship between the retention and consolidation of a new internal model, and the amount of practice and time interval between practice sessions. We employed a visuomotor rotation tracki...

The dataset for the experiment. Each sheet contains the dataset for a paired t- tests for learning plateau, ANOVA for aftereffects and savings respectively. (XLSX)

The present study tested whether remapping of visuomotor correspondence alters automatic motor responses induced by visual stimuli. We hypothesized that the congruency effect, an automatic modulation of motor responses based on stimulus–response congruency, changes in accordance with a new visuomotor correspondence acquired through an adaptation ta...

This study investigated the influences of task constraint on motor learning for a trajectory-based movement considering the speed–accuracy relationship. In the experiment, participants practiced trajectory-based movements for five consecutive days. The participants were engaged in training with time-minimization or time-matching constraints. The re...

In the present study, the influence of simultaneous action execution on motor priming was investigated during movement observation using a simple-reaction task. Although previous studies have reported various effects of priming on motor performance, it has not yet been clarified how an additional source conveying kinetic information would modulate...

The present study investigated interactions between cognitive processes and finger actions called “kusho,” meaning “air-writing” in Japanese. Kanji-culture individuals often employ kusho behavior in which they move their fingers as a substitute for a pen to write mostly done when they are trying to recall the shape of a Kanji character or the spell...

Relation between the construction task performance and Kanji reading score. (TIF)

Relation between the kusho effect of the construction task performance and Kanji reading score. (TIF)

Three sets of Kanji characters used in the experiment and average profiles of each set. The difficulty is based on the average number of correct responses in the static condition in a preliminary experiment conducted in our previous study (Itaguchi et al. 2015). (DOC)

The present study was designed (1) to clarify the relationship between the flow experience and improvements in visuomotor skills, (2) to examine the effects of rotating the axis of a computer mouse on visuomotor skills, and (3) to investigate the effects of sleep for improving visuomotor skills. Participants (N = 18) responded to Perturbation and n...

The main fact that is currently known about the nature of masked L2-L1 noncognate translation priming effects in the lexical decision task is simply that those effects are significant in some studies but not in others. In an effort to better understand these effects, we examined the data pattern for very proficient Japanese-English bilinguals using...

The present study investigated the interactions between motor action and cognitive processing with particular reference to kanji-culture individuals. Kanji-culture individuals often move their finger as if they are writing when they are solving cognitive tasks, for example, when they try to recall the spelling of English words. This behavior is cal...

The goal of this study was to elucidate the underlying mechanisms of hand and tool grasping control. We assumed that there is a single principle-governing grasping control irrespective of its effectors and that the degree of prior experience of the effector determines the smoothness of aperture control. Eight participants performed a reach-to-grasp...

The present study investigated the impact of motor commands to abort ongoing movement on position estimation. Participants carried out visually guided reaching movements on a horizontal plane with their eyes open. By setting a mirror above their arm, however, they could not see the arm, only the start and target points. They estimated the position...

The present study investigated motor planning ability of individuals with Parkinson’s disease. Sixteen patients（Hoehn and Yahr stage 2 ─ 4）and the same number of young controls performed the ESC（End State Comfort）task. In this task, the participants grabbed a horizontal dowel placed on a support either with an overhand or underhand grip, and put a...

The present study investigated the validity of a loading task as a quantitative evaluation tool for sensorimotor function related to an internal model and also as a screening paradigm for their disorders. This study included patients with lesions in the cerebellum, parietal lobe, and basal ganglia. Individuals with Alzheimer disease and healthy old...

Seven patients with parietal lesion carried out a position reproduction task in controlled environment. The task was carried out in environment where participants sat on a chair and closed their eyes, and the horizontal experimental plane was adjusted at the shoulder height of participants. In the task, participants were asked to reproduce a target...

The present study attempted to demonstrate that the indicator arm influences end point distribution in contralateral multi-joint proprioceptive tasks and also that intrinsic physical characteristics of multi-joint arms (arm stiffness) may predict the error pattern. For this purpose, we carried out two types of contralateral localization tasks with...

The present study investigated the effects of two-dimensional arm stiffness and muscle effort required to maintain horizontal arm posture on position-reproduction errors. 12 participants performed a multi-joint position-reproduction task without visual feedback. They were required to indicate a proprioceptively remembered target position with the f...