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Flexible pulse-by-pulse regulation of sensorimotor synchronization is crucial for voluntarily showing rhythmic behaviors synchronously with external cueing; however, the underpinning neurophysiological mechanisms remain unclear. We hypothesized that the dorsal anterior cingulate cortex (dACC) plays a key role by coordinating both proactive and reactive motor outcomes based on contextual mental imagery. To test our hypothesis, a missing-oddball task in finger-tapping paradigms was conducted in 33 healthy young volunteers. The dynamic properties of the dACC were evaluated by event-related deep-brain activity (ER-DBA), supported by event-related potential (ERP) analysis and behavioral evaluation based on signal detection theory. We found that ER-DBA activation/deactivation reflected a strategic choice of motor control modality in accordance with mental imagery. Reverse ERP traces, as omission responses, confirmed that the imagery was contextual. We found that mental imagery was updated only by environmental changes via perceptual evidence and response-based abductive reasoning. Moreover, stable on-pulse tapping was achievable by maintaining proactive control while creating an imagery of syncopated rhythms from simple beat trains, whereas accuracy was degraded with frequent erroneous tapping for missing pulses. We conclude that the dACC voluntarily regulates rhythmic sensorimotor synchronization by utilizing contextual mental imagery based on experience and by creating novel rhythms.

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BACKGROUND: The influence of internal focus (IF) on postural balance needs to be determined when assessing fall risk in older adults. Moreover, the mechanism through which IF is triggered should be elucidated. RESEARCH QUESTION: Does fear unrelated to threats to postural balance modulate IF during postural control? METHODS: The participants were 16 community-dwelling older adults. We generated visual stimuli for neutral and fear conditions using the International Affective Picture System. Participants were assessed for postural control while standing on a stabilometer and looking at projected images. The IF allocated to postural control during task was assessed immediately after the task using the Conscious Movement Processing subscale of the Movement-Specific Reinvestment Scale (MSRS-CMP). Sympathetic activity was assessed using the mean low-frequency/high-frequency ratio (LF/HF), and posture was evaluated using the root mean square area (RMS-A), anteroposterior mean power frequency (MPF-AP), mediolateral MPF, and co-contraction index. Differences (Δ) in the MSRS-CMP, RMS-A and MPF between the neutral/fear conditions and control condition were calculated. Each index was also compared among the control, neutral, and fear conditions. The correlations between ΔMSRS-CMP and postural measures were evaluated. Equivalence tests were conducted to determine whether change of IF was different among conditions. RESULTS: The MSRS-CMP score did not differ significantly among conditions; equivalence was observed. The LF/HF and MPF-AP in the fear condition were higher than in the other conditions. The RMS-A in the fear condition was lower than in the neutral condition. ΔMSRS-CMP and ΔMPF-AP were significantly negatively correlated. SIGNIFICANCE: The results of this study suggest that feelings of fear affect postural control but not the IF of attention. Taken together with previous research, the findings of this study suggest that consideration of the fear-inducing context may be useful in assessments of, and interventions for, older adults with a fall risk.

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Introduction: The human brain can flexibly modify behavioral rules to optimize task performance (speed and accuracy) by minimizing cognitive load. To show this flexibility, we propose an action-rule-based cognitive control (ARC) model. The ARC model was based on a stochastic framework consistent with an active inference of the free energy principle, combined with schematic brain network systems regulated by the dorsal anterior cingulate cortex (dACC), to develop several hypotheses for demonstrating the validity of the ARC model. Methods: A step-motion Simon task was developed involving congruence or incongruence between important symbolic information (illustration of a foot labeled "L" or "R," where "L" requests left and "R" requests right foot movement) and irrelevant spatial information (whether the illustration is actually of a left or right foot). We made predictions for behavioral and brain responses to testify to the theoretical predictions. Results: Task responses combined with event-related deep-brain activity (ER-DBA) measures demonstrated a key contribution of the dACC in this process and provided evidence for the main prediction that the dACC could reduce the Shannon surprise term in the free energy formula by internally reversing the irrelevant rapid anticipatory postural adaptation. We also found sequential effects with modulated dip depths of ER-DBA waveforms that support the prediction that repeated stimuli with the same congruency can promote remodeling of the internal model through the information gain term while counterbalancing the surprise term. Discussion: Overall, our results were consistent with experimental predictions, which may support the validity of the ARC model. The sequential effect accompanied by dip modulation of ER-DBA waveforms suggests that cognitive cost is saved while maintaining cognitive performance in accordance with the framework of the ARC based on 1-bit congruency-dependent selective control.

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Gazing at objects at a near distance (small eye-object distance) can reduce body sway. However, whether body sway is regulated by movement in the mediolateral or anteroposterior direction remains unclear. Galvanic vestibular stimulation (GVS) can induce body tilting in the mediolateral or anteroposterior direction. This study examined the directionality of the eye-object distance effect, using body-tilting GVS manipulations. Ten healthy subjects (aged 21.1 ± 0.3 years) stood on a force plate covered with a piece of foamed rubber and either closed their eyes or gazed at a marker located 0.5 m, 1.0 m, or 1.5 m in front of them. The GVS polarities were set to evoke rightward, forward, and backward body tilts. To compare the effects of eye-object distance in the mediolateral and anteroposterior directions, the root mean square (RMS) of the center of pressure (COP) without GVS was subtracted from the COP RMS during GVS. For swaying in the mediolateral direction, significant visual condition-related differences were found during rightward and forward GVS (p < 0.05). Thus, reductions in mediolateral body sway are more evident for smaller eye-object distances during rightward GVS. It would be appropriate to use body-tilting GVS to detect the directionality of the eye-object distance effect.

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[Purpose] This study aimed to compare physical activities between junior high school and high school female football players in order to explain the factors that predispose to a higher incidence of sports injuries in high school female football players. [Subjects and Methods] Twenty-nine female football players participated. Finger floor distance, the center of pressure during single limb stance with eyes open and closed, the 40-m linear sprint time, hip abduction and extension muscle strength and isokinetic knee flexion and extension peak torque were measured. The modified Star Excursion Balance Test, the three-steps bounding test and three-steps hopping tests, agility test 1 (Step 50), agility test 2 (Forward run), curl-up test for 30 seconds and the Yo-Yo intermittent recovery test were performed. [Results] The high school group was only significantly faster than the junior high school group in the 40-m linear sprint time and in the agility tests. The distance of the bounding test in the high school group was longer than that in the junior high school group. [Conclusion] Agility and speed increase with growth; however, muscle strength and balance do not develop alongside. This unbalanced development may cause a higher incidence of sports injuries in high school football players.

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Downward gazing is commonly observed among patients after a stroke during standing or walking as they struggle to maintain equilibrium. In this study, we aimed to evaluate the effects of fixed gazing and downward gazing on trunk control ability during gait. Sixteen subjects after a stroke (age: 51.3±4.9years) and seven healthy subjects (age: 65.1±3.4years) participated in this study. Participants walked 10m at a comfortable speed while they faced forward (no gaze point), gazed forward (with a fixed gaze point), gazed downward, and gazed downward while concealing their legs. Trunk acceleration was measured using tri-axial accelerometers attached to the back of the upper (C7 spinous process) and lower (L3 spinous process) trunk. The coefficient of attenuation (CoA) of acceleration at the trunk was computed to assess trunk control ability. Results in the stroke group showed that the CoA during fixed-point and downward gazing was better than that while facing forward with no gaze point (p<0.001). In the stroke group, the CoA during gazing downward with their legs concealed was worse than that during downward gazing. Our findings indicate that patients after a stroke might use visual information for reducing their neck oscillation (C7) during fixed-point and downward gazing. Our results indicate that the visual information during downward gazing might work the same as during fixed-point gazing.

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[Purpose] This study aimed to examine whether motor abilities of children with cerebral palsy are related to their problematic behaviors. [Subjects] The subjects were children with mental retardation who were undergoing physical therapy. [Methods] Twenty-one examiners, 13 physical therapists, and 8 occupational therapists treated and examined the subjects by using the Japanese version of the Aberrant Behavior Checklist. The Japanese version of the Aberrant Behavior Checklist scores were compared between the Gross Motor Function Classification System I to III (12 subjects) and Gross Motor Function Classification System IV and V groups (17 subjects). [Results] Lethargy and stereotypy scores significantly differed between the groups, proving that patients with Gross Motor Function Classification System levels IV and V have more severe problematic behaviors. [Conclusion] In this study, only five types of problematic behaviors, namely irritability, lethargy, stereotypy, hyperactivity, and inappropriate speech, were examined. Despite this limitation, the study clarifies that problematic behaviors of children with cerebral palsy, except lethargy and stereotypy, have little relationship with their motor abilities.

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[Purpose] This study explored the roles of physical therapists (PTs) in introducing assistive products, which are essential for living securely and stably at home, and examined how PTs can fulfill these roles more efficiently and effectively. [Subjects and Methods] A questionnaire on introducing assistive products was administered to PTs working at randomly selected hospitals, health-care facilities for the elderly requiring long-term care, home-visit nursing stations, and other such facilities and to PTs providing physical therapy directly to the home-bound elderly disabled. The subjects of the study were 77 PTs who returned valid responses. [Results] For awareness of systems for assistive product's introduction, PTs were more aware of the system based on the Long-Term Care (LTC) Insurance Act than the system based on the Act on Welfare for the Home-Bound Elderly Disabled. For PTs handling assistive product's introduction for the home-bound elderly disabled, approximately 91% of the respondents answered that they had handled some cases of assistive product's introduction, and PTs with longer clinical experience had handled more assistive product's introduction cases. [Conclusion] The results demonstrated that PTs understand the work involved in introducing assistive products work well and that they handle it. The results, however, also suggested that educational and operational improvements are urgently required for PTs introducing assistive products essential for the lives of the home-bound elderly disabled.

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[Purpose] In this study, we examined problematic behaviors of independent-walking and non-independent-walking handicapped children in the infant, school child and adolescent development phases, using the Japanese version of the Aberrant Behavior Checklist (ABC-J) to determine if such behaviors relate to their gross motor abilities. [Subjects and Methods] The subjects were 86 handicapped children who were receiving physical therapy. The subjects were classified into three groups by age. Using the Gross Motor Function Classification System (GMFCS), each group was further divided into an independent-walking group and non-independent-walking group. Thirteen physical therapists and 8 occupational therapists, who were treating the subject children, rated the subjects using the ABC-J. [Results] Significant differences were observed between the independent-walking and the non-independent-walking groups in the stereotypy and lethargy scores of infants. [Conclusion] For schoolchildren and adolescents, no significant differences were observed between the independent-walking and the non-independent-walking groups in their problematic behavior scores.

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Gaze distance and head flexion suppress postural sway in healthy subjects. However, the effects of these factors on stroke patients have not been fully elucidated. In this study, we aimed to evaluate the effects of gaze distance and downward gazing on postural sway in stroke patients. We examined 15 stroke patients and 14 elderly controls. Postural sway was measured in the subjects under the following 5 conditions: eyes fixed forward on a marker located 600 cm ahead (600-cm condition); eyes fixed forward on a marker located 150 cm ahead (150-cm condition); eyes fixed downward (downward condition); the subject facing straight ahead but with eyes closed (closed-forward condition); and the subject facing downward but with eyes closed (closed-downward condition). The root mean squares of the anteroposterior (A-P RMS) and the mediolateral (M-L RMS) directions were determined. The results showed that the short gaze distance decreased the M-L RMS in both the stroke patients and controls (p < 0.001, r = 0.66; p = 0.024, r = 0.43, respectively). In the control group, the downward condition increased the M-L RMS when compared with the 600-cm condition (p = 0.011, r = 0.48). The downward condition decreased the A-P and M-L RMS in the stroke patients when compared with the 600-cm condition (A-P RMS: p < 0.001; r = 0.66, M-L RMS: p = 0.001; r = 0.59). Our results showed that the short gaze distance decreased postural sway in both groups, and downward gazing decreased it only in the stroke group.

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[Purpose] We compared problematic behaviors of children according to the severity of their mental retardation (MR) of intellect as categorized by the Ryouiku Techou in this study, to investigate the influence of MR of intellect on children's problematic behaviors. [Subjects] The subjects were 86 mentally retarded children undergoing physical therapy at hospitals and other facilities. [Methods] The examiners were 13 physical therapists and 8 occupational therapists who worked at the hospital and knew the children well. The examiners individually assessed the subjects using the Japanese version of the Aberrant Behavior Checklist. The subjects were divided into two groups (A and non-A) according to the Ryouiku Techou standard. [Results] No significant differences were observed between the groups except in the items of stereotypy and lethargy. [Conclusion] Problematic behaviors other than stereotypy and lethargy were not influenced by the Ryouiku Techou standard.

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A 52-year-old man was admitted with anemia and slight fever, which he had for the last 2 months. He had undergone replacement of the ascending aorta for acute aortic dissection 10 years previously. Echocardiography demonstrated a flailing thin structure in the anterior wall of the ascending aorta corresponding to the proximal portion of the prosthetic graft. This abnormal echocardiographic finding led us to repeat blood cultivation. We finally detected Enterococcus facium and Staphylococcus epidermidis in his blood sample. We diagnosed this as a graft infection and prepared for surgical re-replacement of the infected graft. While he was waiting for the operation, an infectious aneurysm of a tibialis posterior artery ruptured and an emergency operation was done. Replacement of the infected ascending aorta graft was done thereafter. In surgery, 2-cm-long vegetation was found. It stuck to the graft wall near the former hole used for air removal in the first surgery. The patient recovered fully and left our hospital after 3 months of postoperative antibiotics therapy. This rare case of aortic graft infection long after the original replacement surgery suggests the importance of thorough echocardiographic investigation of prosthetic graft infection as a possible cause of fever of unknown origin.

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An 84-year-old man was referred to the emergency department with severe dyspnea. Based on his physical findings, electrocardiogram, X-ray and echocardiographic findings, congestive heart failure was suspected and drip infusion of prophylactic heparin against intracardiac thrombosis was commenced together with dopamine, nitroglycerin and furosemide. Diuresis occurred and the pulmonary congestion ameliorated remarkably. Starting on the 20th hospital day, the platelet count was gradually reduced (from 256,000 to 55,000 /microl) and the fibrin degradation product concentration rose (27.6 microg/ml). However, prothrombin time was not prolonged (89%), the concentration of antithrombin III was low -normal (69%) and the fibrinogen concentration was high (650 mg/dl). Thus, heparin-induced thrombocytopenia (HIT), rather than disseminated intravascular coagulation (DIC), was suspected. Heparin was withdrawn on the 24th hospital day and replaced by nafamostat mesilate after which the platelet count was restored to 100,000 /microl. Enzyme-linked immunosorbent assay for HIT antibodies was positive. Unfortunately, the patient died from uncontrolled sepsis on the 29th hospital day. At autopsy, platelet-rich thrombi were found in the small pulmonary arteries and intestinal arteries. No evidence of DIC, such as fibrin-rich thrombosis, was observed. This is the first autopsy report of HIT in Japan.

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A 69-year-old man was transferred to our hospital because of severe general fatigue and progressive systemic muscle weakness. He had taken 300 mg/day of cibenzoline for his sustained ventricular tachycardia (VT) for years. At the end of June 2001 he began to feel general fatigue, which slowly progressed to systemic muscle weakness and walking disturbance. On 2nd July 2001, he finally could not stand up by himself. He also felt dyspnea. He was transferred to our emergency room, where he developed severe respiratory depression. Acute myocardial infarction was ruled out based on his ECG and blood chemistry data. Serum BUN and creatinine were elevated to 32 and 2.2 mg/dl, respectively, which returned to normal range 2 weeks later. What we did in our ICU were basically a replacement of cibenzoline with mexiletine and mechanical support of ventilation. As his renal function gradually improved, his spontaneous respiration and muscle power were slowly restored. He was discharged on foot after 1 month of hospitalization. His blood cibenzoline content taken 2 days after the cessation of cibenzoline was 959.6 mg/ml that was abnormally elevated. Considering metabolism and excretion for the 2 days between the cibenzoline cessation and the blood sample drawing, his cibenzoline level on the day of admission must have been extraordinary high. We should be aware of the possibility of abrupt overdosage of cibenzoline even in patients with normal kidney function in the event of a transient or an acute renal dysfunction.

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