Tsunetaka Matoba

The Japanese version of the Effort-Reward Imbalance Questionnaire: A study in dental technicians

To test the psychometric properties and criterion validity of the Japanese version of the EffortReward Imbalance (ERI) Questionnaire (Siegrist, 1996), a survey was conducted among 105 male dental technicians. The Japanese version of the questionnaire was developed through a backtranslation process. Internal consistency and factorial structure were tested and the criterion validity with respect to musculoskeletal symptoms was estimated with the help of a correlation matrix and logistic regression analysis. In psychometric terms, the factorial structure of the scales measuring the components of the theoretical concept was replicated satisfactorily, and internal consistencies of the scales measuring the extrinsic and intrinsic components of the model were appropriate. Significant associations between components of the ERI and musculoskeletal symptoms were found. Logistic regression analysis revealed a significantly elevated risk of musculoskeletal symptoms in participants scoring high on the scale measuring ...

Responsiveness of measures in the effort-reward imbalance questionnaire to organizational changes : a validation study

OBJECTIVE To examine the responsiveness of measures adopted in the effort-reward imbalance (ERI) questionnaire to organizational changes. METHOD For the employees who had been affected by restructuring of their company due to the economic hardship, two consecutive questionnaire surveys were conducted over a specific period. A total of 544 full-time employees responded to both surveys. Changes in four summary measures from the situation-specific model component and the person-specific component, and items/subscales that constitute the questionnaire were evaluated. RESULTS The summary measures on psychological deterioration in the total study population. The deterioration was prevalent in those employees who had presumably experienced the effects of stressful organizational changes related to the restructuring, while improvement in the summary measures was observed for those employees who were promoted during the period. On the whole, the measures for the items of the situation-specific component and subscales for the personal component changed in the expected direction. With regard to ERI, potentially stronger effects of multiple organizational changes on employees were indicated. CONCLUSION Measurements of ERI at work are valid in terms of responsiveness to organizational changes.

Further Observations of the Digital Plethysmography in Response to Auditory Stimuli and Its Clinical Applications

Further observations of the digital plethysmography with auditory stimuli and its clinical applications were performed in patients with vibration disease and heart diseases. The responsive pattern to the auditory stimuli in the digital plethysmogram could be faithfully reproducible if it elapses more than 5 minutes apart between the first stimulus and the second one. The responsive patterns were divided into four types: normal (N), hyperreactive (I and D) types and hyporeactive (P) type.1 The values of urinary catechol amine increased in parallel to the activity level of the autonomic nerve. The hyperreactive type (D) had the highest value of urinary catecholamine, and vice versa. With regard to the age, the elderly was prone to show hyporeactive (P) type, and the young tended to be hyperreactive (D) type. Psychologic factors were examined by Cornell medical index. Neurosis was not necessarily related to the hyperreactive type. In clinical applications, it was observed by this method that the autonomic imbalance in patients with vibration disease, angina pectoris, or hypertension was recovered by the treatment, and the abnormal types of the response recovered to N type. In conclusion, the digital plethysmography with auditory stimuli as one of the autonomic nerve function tests would be much useful and non-invasive method for observation of clinical course and decision of the severity.

Increased left ventricular function as an adaptive response in vibration disease

Vibration disease results from the long-term use of vibrating tools. Vibration, noise, and cold are stressors that impair the human body, inducing vibration disease. From echocardiographic methods, the left ventricular ejection fraction in vibration disease was 79 +/- 4%, a significantly higher value than that in control subjects (75 +/- 6%) (p less than 0.01). The increase in ejection fraction appeared to be due mainly to an increase in left ventricular end-diastolic dimension. The value of the ejection fraction was proportional to the activity of the autonomic nerves. The stroke volume index in patients with vibration disease was also significantly larger than that in the control subjects (p less than 0.001). Electrocardiograms revealed a significantly lower heart rate at rest and an increase in the ratio of T waves to R waves in precordial lead V6. These data suggest that the cardiovascular system in patients with vibration disease provides an adaptive response to the stressors.

The mechanism of a human reaction to vibration stress by palmar sweating in relation to autonomic nerve tone.

Objectives: To clarify the mechanism of a human reaction to vibration stress by palmar sweating in relation to the autonomic nerve tone. Methods: The autonomic nerve tone was divided into four types by using digital photoelectroplethysmography (PTG) with auditory stimuli: normal (N), hyperreactive (I and D), and hyporeactive (P) types. Palmar sweating and digital PTG were simultaneously measured on the right palm and middle finger, respectively, in 20 healthy men. The left hand gripping the handle with a grasp strength of 49 N was exposed to vibration at a frequency of 125 Hz and acceleration magnitudes of 0 m/s2 (as a control), 30 m/s2, or 50 m/s2 for 3 min. The volume of palmar sweating was recorded before, during, and 30 min after vibration load. Three kinds of drugs related to the autonomic nervous system were orally administered to the subjects. Then 80 min after administration, the experiments were repeated. Results: Of 20 subjects, 17 showed normal autonomic nerve tone (N type), and 3 hyperreactive (I type). The palmar sweating reaction to vibration in I-type subjects was greater and lasted longer than that in N-type subjects. Vibration with an acceleration of 50 m/s2 produced the greatest reaction which was about 7 times larger than that at 0 m/s2 and 2.5 times that at 30 m/s2 (P < 0.01). Sulpiride decreased palmar sweating during vibration, while prazosin and scopolamine inhibited it. Conclusions: The palmar sweating reaction to vibration stress was related to the background level of the autonomic nerve tone. The sweating volume was in direct proportion to the acceleration magnitude of vibration. The reaction of palmar sweating to vibration stress may be mediated through both the adrenergic and cholinergic fibers of the autonomic nervous system.

Cardiac hypertrophy accelerated by left cervical sympathectomy in spontaneously hypertensive rats

Cardiac hypertrophy in spontaneously hypertensive rats was accelerated by denervation of the left cervical sympathetic ganglia. Supersensitivity due to denervation may also exist in cardiac muscles.

Cardiac hypertrophy in surgically denervated dogs with aortic stenosis

Left ventricular cell hypertrophy in dogs with aortic stenosis was accelerated by surgical denervation of the left ventricle. We conclude that there are neural mechanisms which, when present, inhibit cardiac cell hypertrophy.

Human response to vibration stress in Japanese workers: lessons from our 35-year studies A narrative review

The occupational uses with vibratory tools or vehicles provoked health disorders of users. We reviewed narratively our articles of 35 yr studies and their related literatures, and considered the pathophysiology of the hand-arm vibration disorders. Concerning the risk factors of health impairments in workers with vibratory tools, there are two conflicting schools of the researchers: The peripheral school emphasizes that vibration only makes predominant impairments on hands and arms, showing typically Raynaud’s phenomenon in the fingers. In the systemic school, the health disorders are produced by combination with vibration, noise and working environment, namely vibratory work itself, leading to diversified symptoms and signs in relation to systemic impairments. Our 35 yr studies have evidently supported the systemic school, including disorders of the central and autonomic nervous systems. The genesis is vibratory work itself, including vibration, noise, cold working environment, ergonomic and biodynamic conditions, and emotional stress in work. Because the health disorders yield in the whole body, the following measures would contribute to the prevention of health impairments: the attenuation of vibration and noise generated form vibratory machines and the regulations on operating tool hours. In conclusion, this occupational disease results from systemic impairments due to long-term occupational work with vibratory tools.

Responses of Myocardial Blood Flows to Whole-Body Vibration in the Dog

Experimentally acute exposure to whole-body vibration resulted in changes in myocardial blood flows in the in vivo dog. Regional myocardial blood flows measured by a hydrogen gas clearance method were increased at a vibration frequency of 120 Hz and decreased at 50 Hz. No appreciable changes were found in presence of a beta-adrenergic blocker. The values of plasma cyclic nucleotides were increased at both frequencies of vibration, more at 50 Hz than at 120 Hz. No significant changes were observed in heart rates and arterial pressure during and after vibration load. These findings suggest that increased myocardial blood flows in response to vibration may be related more to the frequency of vibration than to beta-adrenergic actions.

Noninvasive assessment of the autonomic nervous tone in angina pectoris: an application of digital plethysmography with auditory stimuli.

To assess the relationship between autonomic nerve activity and the angi nal attack, we examined the daily variation of the autonomic tones employing digital plethysmography with auditory stimuli, and also tested the daily varia tion of exercise capacity. Thirteen of 45 cases (28.9%) of spontaneous angina, excluding Prinzmetals angina, complained of typical chest discomfort or pain especially in the morning. They manifested an augmented level of the au tonomic nerve activity and positive stress testing. The remainder did not demonstrate these abnormal findings in the morning. For the 13 cases, calcium antagonists were given orally immediately after awakening. This resulted in the complete relief from chest discomfort or pain. These findings suggest that an autonomic imbalance plays an important role in the pathogenesis of this type of anginal attack. Thus, the estimation of the daily variation of autonomic nerv ous tone would be valuable for the diagnosis and treatment of angina pectoris.