A case of percutaneous septal myocardial ablation in a patient with obstructive hypertrophic cardiomyopathy with accessory mitral valve tissue.

Accessory mitral valve tissue (AMVT) is a rare congenital anomaly that sometimes causes left ventricular outflow tract (LVOT) obstruction. We report the case of a 72-year-old woman with hypertrophic obstructive cardiomyopathy (HOCM) complicated by AMVT. The patient presented at our hospital with palpitations and shortness of breath. Transthoracic echocardiography revealed a diagnosis of HOCM and an abnormal structure inside the LVOT. Transesophageal echocardiography revealed an AMVT. We initially treated the patient with oral medication, but due to side effects, the patient could not take the target dose and her symptoms did not improve. We suggested surgical treatment, but the patient refused. By evaluating the relationship between AMVT and the surrounding tissues using three-dimensional transesophageal echocardiography, we determined that percutaneous septal myocardial ablation (PTSMA) might be successful. The first PTSMA was not effective, but the second procedure showed significant improvement in the pressure gradient and symptoms. The patient with HOCM and concomitant AMVT had a severe LVOT pressure gradient, and PTSMA was performed with excellent results. Since we experienced a rare case and were able to treat it percutaneously, we report our findings in relation to the literature. Learning objective: This case study highlights successful use of percutaneous septal myocardial ablation (PTSMA) in treating a patient with hypertrophic obstructive cardiomyopathy (HOCM) and accessory mitral valve tissue (AMVT). The key objective is to understand PTSMA can be an effective treatment option for HOCM with Type IIa AMVT, characterized by the attachment only to the mitral leaflets, when surgical intervention is not preferred, enhancing management of this rare condition.

Association of cholesterol uptake capacity, a novel indicator for HDL functionality, and coronary plaque properties: An optical coherence tomography-based observational study.

BACKGROUND: Cholesterol efflux from atherosclerotic lesion is a key function of high-density lipoprotein (HDL). Recently, we established a simple, high-throughput, cell-free assay to evaluate the capacity of HDL to accept additional cholesterol, which is herein referred to as "cholesterol uptake capacity (CUC)". OBJECTIVE: To clarify the cross-sectional relationship between CUC and coronary plaque properties. METHODS: We enrolled 135 patients to measure CUC and assess the morphological features of angiographic stenosis by optical coherence tomography (OCT). We estimated the extent of the lipid-rich plaque by multiplying the mean lipid arc by lipid length (lipid index). The extent of the OCT-detected macrophage accumulation in the target plaque was semi-quantitatively estimated using a grading system. RESULTS: Lipid-rich plaque lesions were identified in 125 patients (92.6%). CUC was inversely associated with the lipid index (R = -0.348, P < 0.0001). In addition, CUC was also inversely associated with macrophage score (R = -0.327, P < 0.0001). Conversely, neither circulating levels of HDL cholesterol nor apoA1 showed a similar relationship. CONCLUSIONS: We demonstrated that CUC was inversely related to lipid-rich plaque burden and the extent of macrophage accumulation, suggesting that CUC could be useful for cardiovascular risk stratification.

Comparison of plasma fatty acid binding protein 4 concentration in venous and capillary blood.

Circulating fatty acid binding protein 4 (FABP4) is associated with various diseases and simple and less invasive techniques for assessment of FABP4 concentration are required in clinical research setting. The purpose of the present study was to assess the correlation of plasma FABP4 concentration between venous and capillary blood in healthy young adults. Twenty-eight healthy young adults aged from 20 to 26 years (mean age, 22.2 ± 1.4 years, 14 males and 14 females) were included. Paired resting blood samples were taken from the cubital vein (venous) and fingertip (capillary) blood. Plasma FABP4 concentration in both blood was analyzed by enzyme-linked Immunosorbent assay. Plasma FABP4 concentration did not differ significantly between venous and capillary blood (-0.11± 0.75 ng/mL, p = 0.447, 95%CI: -0.402-0.182). Pearson's correlation coefficient for plasma FABP4 concentration between venous and capillary blood samples suggests strong correlation (r = 0.961, p < 0.001). The Bland & Altman plot showed a non-significant bias (-0.11 ± 0.75 ng/mL, p = 0.684) and the 95% limits of agreement ranged from -1.59 to 1.37 ng/mL. FABP4 concentration in both venous and capillary blood was significantly higher in females than in males (venous blood: p = 0.041; capillary blood: p = 0.049). These results suggest that capillary blood sampling can detect gender difference and is useful for the assessment of FABP4 concentration.

Left Ventricular Diastolic Function During the Normal Peripartum Period.

BACKGROUND: Because cardiovascular function and hemodynamics markedly change during pregnancy, our aim was to elucidate left ventricular (LV) diastolic function in pregnant women.Methods and Results:We prospectively collected the data of 397 pregnant women treated between 2012 and 2013. We evaluated their LV systolic and diastolic functions via echocardiography during the 3rd trimester (28-30 weeks' gestation) and within 4 days of delivery. Additionally, we analyzed the cardiac geometry: relative wall thickness and LV mass index (LVMI). Diastolic dysfunction was defined as early diastolic mitral annulus velocity (e') <7 cm/s and peak early filling velocity (E)/e' ratio >15. The pregnant women were 33.7±5.0 years old and the prevalence of hypertensive disorders in pregnancy (HDP) was 4.0%. LV systolic function was preserved in all pregnant women. However, diastolic function significantly decreased after delivery (mean e': 12.6 vs. 11.6 cm/s, P<0.0001; median E/e' ratio: 6.4 vs. 7.3, P<0.0001). Diastolic function after delivery was associated with the prevalence of HDP (P=0.035) and was correlated with age (R=-0.17, P=0.0009) and LVMI (R=-0.30, P<0.0001). However, these changes in diastolic function remained within the normal range and only 1 woman (1/397, 0.3%) had LV diastolic dysfunction after delivery. CONCLUSIONS: LV diastolic function decreased after delivery in pregnant women but was within the normal range.

Factors associated with increased levels of brain natriuretic peptide and cardiac troponin I during the peripartum period.

BACKGROUND: We aimed to investigate the values and the changes of brain natriuretic peptide (BNP) and cardiac troponin in pregnant women. METHODS AND RESULTS: We prospectively collected the data of 405 pregnant women who were treated at Japanese general hospital between 2012 and 2013. We analyzed their laboratory data and echocardiographic findings during the third trimester (28-30 weeks' gestation) and within 4 days of delivery. In addition, we evaluated the factors associated with elevation of BNP and cardiac troponin I (cTnI) levels. The pregnant women were 33.8 ± 5.0 years old and the prevalence of pregnancy induced hypertension (PIH) and placental abnormality was 4.2% and 2.5%, respectively. BNP levels increased after delivery (13.2 pg/mL vs. 23.5 pg/mL; P <0.001), correlated with increased left ventricular diastolic dimension (P = 0.035), left atrial dimension (P <0.001), and decreased hemoglobin (P <0.001). Moreover, cTnI levels increased to over 0.015 ng/mL after delivery in 4.0% of pregnant women. In multivariate analysis, PIH (OR: 18.71, P = 0.003), placental abnormality (OR: 26.78, P = 0.007), and decreased hemoglobin after delivery (OR: 2.59, P <0.001) were the factors associated with elevated cTnI. CONCLUSIONS: BNP levels increased in association with cardiac chamber enlargement and decreased hemoglobin after delivery. Additionally, the factors affecting elevated cTnI levels were related to labor and delivery.

Peri-strut low-intensity area assessed by midterm follow-up optical coherence tomography may predict target lesion revascularisation after everolimus-eluting stent implantation.

AIMS: Peri-strut low-intensity area (PLIA) assessed by optical coherence tomography (OCT) has been reported as a potential marker of abnormal neointimal healing. We aimed to evaluate the impact of PLIA on clinical events and its risk factors. METHODS AND RESULTS: We enrolled 264 consecutive patients treated with an everolimus-eluting stent (EES) who underwent follow-up OCT six to 12 months after stenting. Target lesion revascularisation (TLR) was evaluated at a mean 42.6 months after stenting. PLIA was identified in 102 patients; 162 patients did not exhibit PLIA. Multivariate Cox hazard regression analysis indicated that the presence of PLIA (PLIA+) was an independent risk factor for an increased incidence of TLR (hazard ratio [HR]: 4.608, p=0.003). In both the early (<1 year) and late (>1 year) phases, the incidence of TLR was significantly higher in the PLIA+ group (p<0.001 and p<0.001, respectively). In the Cox hazard regression analysis, current smoking and increased C-reactive protein level were independently associated with PLIA+ (HR: 1.737, p=0.009; HR: 2.435, p=0.008, respectively). CONCLUSIONS: The presence of PLIA on midterm OCT was associated with TLR after EES implantation. Detailed stent assessment by midterm OCT may help to predict stent failure in patients treated with EES.

Data on impact of monocytes and glucose fluctuation on plaque vulnerability in patients with coronary artery disease.

Data presented in this article are supplementary material to our research article entitled "Impact of CD14++CD16+ monocytes on coronary plaque vulnerability assessed by optical coherence tomography in coronary artery disease patients" [1]. This article contains the data of study population, diagnostic ability of CD14++CD16+ monocytes to identify thin-cap fibroatheromas, and association between laboratory variables and plaque properties.

Impact of CD14++CD16+ monocytes on coronary plaque vulnerability assessed by optical coherence tomography in coronary artery disease patients.

BACKGROUND AND AIMS: This study examined the impact of CD14++CD16+ monocytes on coronary plaque vulnerability, as assessed by optical coherence tomography (OCT), and investigated their association with daily glucose fluctuation. Although increased CD14++CD16+ monocyte levels have been reported to increase cardiovascular events, their impact on coronary plaque vulnerability in coronary artery disease (CAD) patients with or without diabetes mellitus (DM) remains unclear. METHODS: This prospective observational study included 50 consecutive patients with CAD, receiving lipid-lowering therapy and undergoing coronary angiography and OCT. Patients were divided into 3 tertiles according to the CD14++CD16+ monocyte percentages assessed by flow cytometry. Standard OCT parameters were assessed for 97 angiographically intermediate lesions (diameter stenosis: 30-70%). Daily glucose fluctuation was analyzed by measuring the mean amplitude of glycemic excursion (MAGE). RESULTS: CD14++CD16+ monocytes negatively correlated with fibrous cap thickness (r = -0.508, p < 0.01). The presence of thin-cap fibroatheroma (TCFA) was increased stepwise according to the tertile of CD14++CD16+ monocytes (0 [tertile 1] vs. 5 [tertile 2] vs. 10 [tertile 3], p < 0.01). CD14++CD16+ monocytes were a significant determinant of TCFA (OR 1.279, p = 0.001). In non-DM patients, a significant relationship was found between CD14++CD16+ monocytes and MAGE (r = 0.477, p = 0.018). CONCLUSIONS: CD14++CD16+ monocytes were associated with coronary plaque vulnerability in CAD patients with well-regulated lipid levels both in DM and non-DM patients. Cross-talk between glucose fluctuation and CD14++CD16+ monocytes may enhance plaque vulnerability, particularly in non-DM patients. CD14++CD16+ monocytes could be a possible therapeutic target for coronary plaque stabilization.

The impact of serum trans fatty acids concentration on plaque vulnerability in patients with coronary artery disease: Assessment via optical coherence tomography.

BACKGROUND AND AIMS: Recent epidemiological studies have showed that excessive intake of trans fatty acids (TFA) can be a residual risk for the development of coronary artery disease (CAD) even under medical management, including statins. This study aimed at investigating the association between lipid profile, including serum TFA concentration, and plaque vulnerability using optical coherence tomography (OCT). METHODS: The level of serum elaidic acid, a major TFA component, was measured using gas chromatography in 161 consecutively enrolled patients with CAD under guideline-directed risk factor management. OCT was performed to evaluate morphological features of angiographic intermediate stenosis (30% < diameter of stenosis <70%). OCT data were also used to measure lipid index (LI), defined as mean lipid arc multiplied by lipid length, and determine the presence of thin-cap fibroatheroma (TCFA), defined as a lipid-rich plaque with the smallest fibrous cap thickness <65 µm and the maximal arc >90°. RESULTS: Among 190 lesions assessed using OCT, 49 TCFAs were detected. In patients with at least one TCFA lesion, levels of elaidic acid (12.9 ± 4.9 vs. 10.3 ± 4.3 µmol/L, p = 0.001), triglycerides (169 ± 81 vs. 130 ± 60 mg/dL, p = 0.005), and remnant-like particle cholesterol (10.4 ± 6.5 vs. 7.7 ± 4.7 mg/dL, p = 0.005) were higher than in those without TCFAs. Generalized estimating equations identified elaidic acid level as the independent risk factor of TCFA. LI had a positive correlation with elaidic acid level (r = 0.173, p = 0.025). CONCLUSIONS: TFA may affect plaque vulnerability in patients with CAD. Serum TFA concentration may represent another cardiovascular risk factor during conventional risk factor management.

Characteristics of the life habits of obese students at one of Japan's National Colleges of Technology.

Aim This study clarified the characteristics of life habits of obese Japanese male students at the National Colleges of Technology, Japan. Materials and methods Healthy students aged 15-19 years answered a questionnaire containing 21 items on the following five categories of life habits: general exercise, meals, sleeping, leisure activity and illness or injury history. The subjects were divided into three groups based on the criteria of body mass index (BMI) and body fat percentage (%BF): non-obese (%BF < 20%, n = 420), overweight obese (%BF ≥ 20% and BMI ≥ 25, n = 99), and hidden obese (%BF ≥ 20% and BMI < 25, n = 60). The mean differences in waking time, bedtime and amount of time spent walking, sleeping and watching TV per day were examined using one-way analysis of variance (ANOVA) and chi-square tests for each item. Results The overweight obese and hidden obese groups engaged in less exercise time, were more likely to eat until they were full at meals and were less likely to eat between meals or late at night than the non-obese group. In addition, the non-obese group had significantly later waking times and significantly less TV-watching time than the overweight obese group. There were no significant differences with respect to leisure activity and illness or injury history among the three groups. Many students in all groups had regular waking times and were not performing any leisure activities. Conclusion The findings suggest that obese students may need further guidance to help them maintain a healthy life and appropriate weight.

Effects of daily glucose fluctuations on the healing response to everolimus-eluting stent implantation as assessed using continuous glucose monitoring and optical coherence tomography.

BACKGROUND: Several studies have revealed that glucose fluctuations provoke oxidative stress that leads to endothelial cell dysfunction, progression of coronary atherosclerosis, and plaque vulnerability. However, little is known regarding their effect on neointimal growth after stenting in patients with coronary artery disease (CAD). We aimed to investigate the effects of glucose fluctuations on neointimal growth after everolimus-eluting stent (EES) implantation. METHODS: This study examined 50 patients who underwent a 9-month follow-up using optical coherence tomography (OCT) after EES implantation. Glucose fluctuation was expressed as the mean amplitude of glycemic excursion (MAGE), and was determined via continuous glucose monitoring before stenting. At the OCT follow-up, we evaluated the percentage of uncovered struts and three-dimensional uniformity of neointimal distribution by calculating the mean neointimal thickness (NIT) within 360 equally-spaced radial sectors for every 1-mm cross-sectional OCT analysis, and assessed the incidence of major adverse cardiovascular events (MACE). RESULTS: We evaluated 60 lesions in 50 patients. Linear mixed effect models were used to explore the influence of different variables on variability in NIT and the percentage of uncovered struts and to adjust for covariates. Univariate analysis showed that MAGE was most strongly correlated with the previously mentioned OCT measurements (coefficient ß ± standard error = 0.267 ± 0.073 and 0.016 ± 0.003, t = 3.668 and 6.092, both P < 0.001, respectively). In multivariate analysis, MAGE had the strongest effect on variability in NIT (coefficient ß ± standard error = 0.239 ± 0.093, P = 0.014) and the percentage of uncovered struts (coefficient ß ± standard error = 0.019 ± 0.004, P < 0.001). Five lesions in four patients required target lesion revascularization (10.0 %) at a mean duration of 9 months after EES implantation. Compared to non-MACE cases, cases of MACE exhibited a significantly higher MAGE (99 vs. 68; P = 0.004), maximum NIT (580 vs. 330 µm; P = 0.002), and variability in NIT (100 vs. 65; P = 0.007), although there was no significant difference in these groups' HbA1c levels. CONCLUSIONS: Glucose fluctuation may affect vessel healing after EES implantation in patients with CAD who are receiving lipid-lowering therapy. Therefore, glucose fluctuations may be an important target for secondary prevention after coronary stenting, which is independent of dyslipidemia control.

Comparison of effects of α-Glucosidase inhibitors and glinide drugs on endothelial dysfunction in diabetic patients with coronary artery disease.

BACKGROUND: Studies have shown that repeated post-prandial hyperglycemia may play an important role in the development of atherosclerosis by suppressing endothelial function. α-Glucosidase inhibitors (α-GIs), which reduce post-prandial hyperglycemia without stimulating insulin secretion, significantly reduce the risk of coronary artery disease (CAD), whereas glinides, which improve post-prandial hyperglycemia through post-prandial insulin secretion, do not appear to affect CAD. METHODS AND RESULTS: A total of 104 diabetic patients with CAD were randomly divided into 2 groups: those treated with miglitol (M-group; n=52) and those treated with nateglinide (N-group; n=52). After 4 months' treatment, although hemoglobin A1c and 1,5-anhydroglucitol were significantly improved in both groups, only the M-group had significant reductions in insulin resistance index and triglyceride/high-density lipoprotein cholesterol (TG/HDL-C; a beneficial index for assessing the presence of small dense low-density lipoprotein, and a marker of atherogenic dyslipidemia). Furthermore, only the M-group had improvement in percentage flow-mediated dilatation (%FMD) and reactive oxygen metabolites. In the M-group, multiple regression analysis showed that improvement in TG/HDL-C, in addition to 1,5-anhydroglucitol, was an independent predictor of improvement in %FMD. CONCLUSIONS: The ameliorating effect of α-GI on post-prandial hyperglycemia without stimulating insulin secretion may improve atherogenic dyslipidemia by reducing insulin resistance. These effects are associated with its beneficial impact on oxidative stress, consequently leading to an improvement in endothelial dysfunction.

Changes in the physical functions of pre-frail elderly women after participation in a 1-year preventative exercise program.

AIM: The present study clarifies the effects of participation in a preventative health classroom program (exercise program) for 1 year on the physical functions of pre-frail elderly individuals in comparison with healthy elderly individuals. METHODS: Participants in the study included 28 elderly pre-frail female participants and 28 elderly healthy female participants. Participants engaged in the exercise program for 1 year. There was no significant age or physical differences between both groups. Before and after the exercise program, the following physical function tests were carried out: grip strength, one-legged balance with eyes open, 5-m walking time and a timed up & go (TUG). RESULTS: The pre-frail elderly group tested significantly lower in the one-legged balance with eyes open test and the TUG test compared with the healthy elderly group. The 5-m walking time test improved significantly in both groups, but the TUG improved only in the pre-frail elderly group. Conversely, the grip strength and one-legged balance with eyes open tests remained unchanged. CONCLUSION: Improvements in the TUG and 5-m walking time tests were found in the pre-frail elderly group after the 1-year exercise program. Their results in the TUG test might be greater than those among the healthy elderly individuals.

Age differences between the controlled force exertion measured by a computer-generated sinusoidal and a bar chart display.

It is important to develop an accurate method of measuring controlled force exertion. This study examined the age differences between the controlled force exertion measured by a sinusoidal waveform and a bar chart display. The participants comprised 175 right-handed male adults aged 20-86 years. The participants were divided into three age groups: young (n=53), middle-aged (n=71), and elderly (n=51). They matched the submaximal grip strength exerted by their dominant hand to changing demand values displayed as either a sinusoidal waveform or a bar chart appearing on a personal computer screen. The participants performed the controlled force exertion test three times with a 1-min inter-trial interval using their dominant hand. The dependent variable was the total sum of the percentage values of the differences between the demand value and grip exertion value for more than 25s. The coefficient of variance had almost the same range in all age groups in both displays (CVSW=28.0-36.9, CVBC=29.1-32.6), but the elderly group showed a somewhat higher value with the sinusoidal waveform. Significant correlations were found between the scores with sinusoidal waveform and bar chart displays in the young, middle-aged, and elderly groups (r=0.47-0.68), but the correlations did not differ significantly between the age groups. Scores over 1500% in sinusoidal and bar chart display were found in one and two participants, respectively, in the middle-aged group and in 12% and 16% of the participants, respectively, in the elderly group. Furthermore, among all participants, only 8% of participants in the elderly group scored over 1500% in both displays. Scores over 1500% in both displays are considered to be considerably worse in controlled force exertion than lower scores.

Different gripping intervals in reproducibility of force-decreasing curve and muscle oxygenation kinetics during sustained maximal gripping.

The purpose was to examine the properties and reproducibility of the force-decreasing curve and muscle-oxygenation kinetics measured by near infrared spectroscopy in sustained isometric grip and rhythmic repeated grip measurements using various contraction intervals (2 to 5 sec.). 10 healthy young adults performed both grip tests for 6 min., during which muscle-oxygenation kinetics were measured. The intraclass correlation coefficients of the time to reach the minimum value for oxygenated hemoglobin and myoglobin tended to become lower with longer relaxation time, especially over a 3-sec. interval. Although blood-flow obstruction closely influences the initial decreasing grip force during both grip tests with a 2-sec. interval, the decreasing grip force during rhythmic repeated gripping with over a 3-sec. interval is low. Hence, the physiological mechanism related to rhythmic repeated grip with over a 3-sec. interval may differ from that related to sustained isometric grip and rhythmic repeated grip with a 2-sec. interval.

Examination of validity of fall risk assessment items for screening high fall risk elderly among the healthy community-dwelling Japanese population.

We aimed to examine the validity of fall risk assessment items for the healthy community-dwelling elderly Japanese population. Participants were 1122 healthy elderly individuals aged 60 years and over (380 males and 742 females). The percentage who had experienced a fall was 15.8%. This study used fall experience and 50 fall risk assessment items representing the five risk factors (symptoms of falling, physical function, disease and physical symptom, environment, and behavior and character), as we described before. The accuracy of predicting fall experience from the total score or each risk factor score was examined by discriminant analysis. The percentage correctly distinguishing the faller from the total score was 14.4%, and that from the five risk factor scores was 39.7%. This percentage, when using each risk factor score as an independent variable, was 42.5% (symptom of falling), 0.6% (physical function score), 0.6% (disease and physical symptoms score), 0.0% (environment score), and 1.1% (behavior and character score), respectively. The best predictor of fall experience of the community-dwelling elderly was the "symptom of falling" score. For fall risk assessment of the community-dwelling elderly, both of screening of fall risk level and assessing risk profile comprehensively is important.

Static one-legged balance in soccer players during use of a lifted leg.

The goal was to describe static one-legged balance during use of a lifted leg and to compare balance between the dominant and nondominant legs of soccer players. Participants were 17 male soccer players and 17 untrained male students (control). Balance ability was evaluated with four sway measures: sway velocity, anterior-posterior sway, medial-lateral sway, and high-frequency sway. Soccer players had smaller magnitude mean anterior-posterior and medial-lateral sway than untrained students. Although mean sway velocity and anterior-posterior sway were higher with the dominant leg than in the nondominant leg of the control group, there was no significant difference on any sway factor between the two legs of the soccer group. In conclusion, the soccer players were observed to have superior static one-legged balance during use of a lifted leg, and there is no difference in balance for the two legs in the soccer group.

Reproducibility of controlled force exertion measurements computed by a quasi-random target-pursuit system.

The reproducibility of measurements and measurement error of controlled force exertion was examined based on target-pursuit of quasi-random waveforms. 30 college students were required to match their grip strength to a changing demand value appearing on the display of a personal computer using visual images in the form of four different quasi-random waveforms. The variable was the sum of the differences over time between the demand value and produced grip strength. Intraclass correlation coefficients (ICCs) for measurements one day apart were low or moderate for quasi-random waveform displays, with mean frequencies of 0.01, 0.05, 0.07, and 0.09 Hz (ICCs= .37, .73, .57, and .57, respectively). Measurements at a 1-wk. interval showed statistically significant improvements in performance at all quasi-random waveform frequencies. The total error between test and retest, and the systematic error between tests, remained relatively small as mean frequency increased. Tests that use the quasi-random waveform displays of 0.05 Hz and over can be useful in documenting controlled force exertion.

Provisional norms by age group for Japanese women on the controlled force exertion test using a quasi-random display.

This study examined age group and individual differences in the controlled force exertion test using quasi-random display and proposed a provisional norm in 249 female participants who were right-handed and aged 15 to 84 years. The participants matched their submaximal grip strength exertions to changing demand values, appearing as a quasi-random wave on the display of a personal computer. The quasi-random waveform changed in pi with amplitude and in pi/2 with frequency (peak and mean frequency were 0.1 Hz in both waveforms). The participants performed the controlled force exertion test three times at 1-min. intervals (single trials were 40 sec.), after one practice trial using the dominant hand. The total sum of the percent of differences between the demand value and the grip exertion value for 25 sec. was used as an evaluation parameter. Measurements showed a right-skewed distribution, which was normal after logarithmic transformation. Analysis of variance showed significant differences in the means of each age group, and test performance decreased after 50 years of age. Norms for each age group were established. An individual's controlled force exertion by the provisional norm as devised in this study can be properly evaluated.

Influence of measurement order by dominant and nondominant hands on performance of a pursuit-rotor task.

This study examined the effect of bilateral transfer and performance variation on 10 trials of a pursuit-rotor task. 95 right-handed healthy men (M age = 21.0 yr., SD = 3.6) were randomly divided into Right-Left (R-L: n = 50) and Left-Right (L-R: n = 45) groups. The former performed the task with the right hand first and the latter group used the left hand first. Target contact times on the pursuit-rotor task improved at about the same rate. Contact times by the left hand after using the right hand were longer than those when the left hand was used first. Although variation of contact times converged with repeated trials, when the left hand was used first, the performance variation remained large for right-handed participants.