| Human recognizes the shape,material,temperature and roughness of objects through touch.Tactile motion perception plays an important role in recognizing and grasping objects that allows human clearly perceive hand-object interactive movement.To study how tactile motion information forms and quantifies subjective perception is important to understand the tactile perception system.In addition,the influence of age and disease on tactile motion perception remains unknown.Previous studies indicated that patients with Parkinson’s disease(PD)have not only motor impairment but also tactile sensation impairment.As to our knowledge,there is no systematic investigation on the quantitative evaluation method for impaired tactile function in PD.The goal of this study is to develop a reliable tactile stimulator and to systematically evaluate the tactile perception with the factors of age and PD.The tactile stimulator is an essential tool for exploring tactile perception.In this study,a square-wave ball tactile stimulator has been developed with small size,convenient carry,and accurate adjustment of depth.In addition,it can conduct a 360-degree range of stimulus directions and a wide range of stimulus speeds to provide a variety of stimulus modes.We developed a control system for the stimulator,including the motor control program,the circuit board and the software interface of the control system.In addition,we performed a series of psychophysical experiments to reveal the influence of stimulus parameters in tactile motion perception.The results showed the tactile direction perception of healthy young subjects didn’t affected by stimulus speed and maintained consistent bias under different stimulus directions.In terms of stimulus frequency lower than 40 Hz,the perceived speed of healthy positively linearly correlated with the stimulus frequency.As the stimulus frequency higher than 40 Hz,the perceived speed positively correlated with the stimulus frequency(the growth rate is very low)and negatively correlated with the stimulus wavelength of ball.Comparing the tactile motion perception among Parkinson’s patients(58.3±6.96y),healthy old people(55.58±4.04y)and healthy young people(24.53±3.02y),we found that Parkinson’s patients had sensory confusion in direction perception and the sensitivity of speed perception was significantly decrease.These findings will provide a reference for exploring the mechanism of tactile defect in Parkinson’s patients.The proposed tactile stimulator provides a efficient tool to evaluate and quantify tactile sensation for clinical and neuroscience studies. |
