1958 年 47 巻 8 号 p. 967-985
For a reliable measurement of vibratory sensation, the amplitude of the minimal perceptible vibration-the threshold values of the vibratory sensation-should be employed. Employing a moving coil type vibrator with a BaTi O3 ceramic element to determine the absolute values of amplitude, changes of vibratory sensation with advancing age and in diabetes mellitus were investigated.
The threshold value of vibratory sensation was expressed as the logarithm of the minimal perceptible vibration amplitude expressed in 10-4mm. Frequency of 150c/s was used because it was easily perceptible giving accurate results.
As an intimate correlation was found among volar sides of the tip of the first, second and fifth finger and among plantar sides of the tip of the first toe of right and left side, volar side of the tip of the right second finger and plantar side of the tip of the right first toe were selected for the test.
Among 2000 subjects between 10 and 82 years of age, the threshold values of finger tip were distributed between 0.1 (1.25×10-4mm) and 0.8 (6.31×10-4mm) in normal group and above 0.8 in abnormal group, which increased with advancing age. The threshold values of toe tip were distributed between 0.8 (6.31×10-4mm) and 1.9 (79.5×10-4mm) and values above 1.9 was observed in increasing frequency with advancing age.
Those who had high threshold values of vibratory sensation were found to have arteriosclerosis, abnormal tendon reflexes, and decreased mental activity in many cases.
In 93 diabetic subjects of less than 59 years of age, decreased vibratory sensation was observed more frequently than the non-diabetic group of similar age, while in persons of more than 60 years of age, such difference was not recognized between a group of 49 diabetics and non-diabetic control.