Humans ; Touch ; Touch Perception

Touch ; Signal Transduction ; Receptors, G-Protein-Coupled ; Touch Perception

In this study, a recall experiment and a recognition experiment were designed to assess the human wrist's short-term memory characteristics of tactile perception on vibration intensity, by using a novel homemade vibrotactile display device based on the spatiotemporal combination vibration of multiple micro vibration motors as a test device. Based on the obtained experimental data, the short-term memory span, recognition accuracy and reaction time of vibration intensity were analyzed. From the experimental results, some important conclusions can be made: (1) The average short-term memory span of tactile perception on vibration intensity is 3 ± 1 items; (2) The greater difference between two adjacent discrete intensities of vibrotactile stimulation is defined, the better average short-term memory span human wrist gets; (3) There is an obvious difference of the average short-term memory span on vibration intensity between the male and female; (4) The mechanism of information extraction in short-term memory of vibrotactile display is to traverse the scanning process by comparison; (5) The recognition accuracy and reaction time performance of vibrotactile display compares unfavourably with that of visual and auditory. The results from this study are important for designing vibrotactile display coding scheme.
Female ; Humans ; Male ; Memory, Short-Term ; Reaction Time ; Touch ; Touch Perception ; Vibration ; Wrist

This paper discusses the short-term memory of vibro-tactile perception of human fingertips. By using a self-developed vibro-tactile expression device, a recall experiment was firstly carried out among 20 subjects aged 20-30 (10 males and 10 females) to discover the memory span about the vibro-tactile perception of human fingertips. Within this memory span, a cognitive experiment analyzing the recognition accuracy and the reaction time was carried out. The results showed: (1) The vibro-tactile memory span of human fingertip is 4 ± 1; (2) The vibro-tactile memory span increases as the discrete intensity between vibration stimuli increases; (3) Too long or too short vibration duration will reduce the vibro-tactile memory span, and the optimal vibration duration for men is 400 ms, for women is 300 ms; (4) The more the number of vibration stimuli is perceived by the human fingertip, the lower the recognition accuracy and the longer the reaction time it needs; (5) Compared with the vibration stimuli in disorder, people are more likely to remember the vibration stimuli in increasing/decreasing order; (6) The information extraction mechanism of the short-term memory about fingertip vibro-tactile perception bases a point to point scanning process among these stimuli. These results help to understand the human fingertip tactile characteristics and provide a physiological basis for the study of tactile feedback technologies.
Adult ; Female ; Fingers ; Humans ; Male ; Memory, Short-Term ; Touch ; Touch Perception ; Vibration ; Young Adult

Many applications in virtual reality and telerobot call for the implementation of displaying the human softness haptics on the object being touched. Although there are lots of literatures on discrimination threshold for displacement, force magnitude, shape and viscosity, there is still a lack of research on remembrance of softness haptic perception in human fingertips. Such research is needed in designing haptic rendering and display system. In this paper, a novel softness haptic display device based on deformable length of elastic element control was adopted as a test device to study the human fingertip's ability of remembrance of softness haptic perception. According to the recall experiment and recognition experiment, the softness haptic memory span and reaction time were discussed. From the experimental results, some important conclusions have been obtained: (1) human softness haptic memory span is 3 to 4 items, which is smaller than visual memory span and auditory memory span; (2) it is more difficult for people to remember hard objects than soft objects.
Adult ; Female ; Form Perception ; physiology ; Humans ; Male ; Mental Recall ; Touch ; physiology ; Visual Perception

BACKGROUNDThe ability of patients to discriminate thickness can change with time after the insertion of new complete dentures, and this adaptation may differ according to the experiences of the patients. If so, an education program to reinforce the oral functions may be needed. This study was to evaluate patients' ability to discriminate thickness by comparing experienced and non-experienced denture wearers after the insertion of new complete dentures.

METHODSForty edentulous patients with a skeletal Class I jaw relationship without any temporomandibular disturbances were in the study. After insertion of new complete dentures, all patients were tested for discrimination threshold for interocclusal thickness. The thickness perception test was repeated on days 1, 7, and 30 after the insertion of new dentures. The discriminatory ability was assessed with steel and aluminium foils placed between the upper and lower central incisor teeth. The records included the duration of wearing dentures. The data were subjected to statistical analysis of two-way ANOVA, multiple comparison test and Student's t test.

RESULTSDiscrimination of tactile ability significantly increased over 30 days in experienced denture wearers as compared with non-experienced patients (P < 0.001). The difference in thickness perception threshold was statistically significant between the two groups (P < 0.001).

CONCLUSIONAdaptation and denture experience can affect thickness discrimination of complete denture wearers.

Aged ; Denture, Complete ; Female ; Humans ; Male ; Middle Aged ; Perception ; Sensory Thresholds ; Touch

Haptic feedback plays a significant role in minimally invasive robotic surgery (MIRS). A major deficiency of the current MIRS is the lack of haptic perception for the surgeon, including the commercially available robot da Vinci surgical system. In this paper, a dynamics model of a haptic robot is established based on Newton-Euler method. Because it took some period of time in exact dynamics solution, we used a digital PID arithmetic dependent on robot dynamics to ensure real-time bilateral control, and it could improve tracking precision and real-time control efficiency. To prove the proposed method, an experimental system in which two Novint Falcon haptic devices acting as master-slave system has been developed. Simulations and experiments showed proposed methods could give instrument force feedbacks to operator, and bilateral control strategy is an effective method to master-slave MIRS. The proposed methods could be used to tele-robotic system.
Feedback ; Humans ; Minimally Invasive Surgical Procedures ; instrumentation ; Robotics ; instrumentation ; Surgery, Computer-Assisted ; instrumentation ; Touch Perception

This study examined the types of touch received by elderly patients from nurses, and explored the elderly patient' and nurses' perceptions of touch occurring during nursing activities. Non-participant observation and semi-structured interviews were the methods employed for data collection. The study subjects were composed of 24 nurses of the three medical wards, and their 83 elderly patients who were hospitalized at S Hospital in Seoul from February 15th to March 15th in 1996. The Observation Schedule, the Perception of Touch Instrument, and the Patient classification were study instruments. The most common types of touch occurring during the nurse-elderly patient interactions were : task touch(82.9%), caring touch(4.9%), and concurrent type of touch (12.2%). The mean score of the elderly patients' perception of touch was higher at 30.45(range 5-35)compared to the mean score of the nurses' perception of touch which was 23.01(range 5-35). Elderly patients received the nurses' touch much more positively than the nurses. But the two scores were not significantly correlated(r=.06, 29). The elderly patient's touch perception score was higher(p<.05) in the group that was touched upon approach than the group was touched later. Elderly patients preferred caring touch to task touch, but it was not significant. Nurses' touch perception scores were higher(p<.05) for female than male. Elderly patients felt most comfortable when the nurses administered the touch on their painful site.
Aged ; Appointments and Schedules ; Classification ; Data Collection ; Female ; Humans ; Male ; Nursing ; Seoul ; Touch Perception

OBJECTIVETo investigate the role of activated brain regions in Parkinson's disease (PD) during tactile stimulation.

METHODSTwenty-one patients with early PD[mean age (60.43 +/-9.65)y] and twenty-two age-matched healthy controls [mean age (59.23 +/-11.12)y] were enrolled in the study. All the patients were tested by the United Parkinson Disease Rating Scale (UPDRS) as the evaluation of the disease severity. A block design was used when the finger tactile stimulation was given to the subjects. The hypoactive and hyperactive regions of PD patients were confirmed first, which were identified as regions of interest (ROI). ROI analysis was performed to quantify BOLD signal changes when subjects were under tactile stimulation. The correlations of signal changes with disease severity, and correlations of hyperactive with hypoactive regions were analyzed.

RESULTSRight primary sensory and motor cortex, right supplementary motor area (SMA), bilateral caudates, bilateral precuneus, bilateral occipital visual cortex and left middle temporal gyrus were hypoactivated in PD, while right prefrontal cortex (PFC) and right caudate were hyperactivated. The hypoactivation of right SMA was negatively correlated with disease severity. All the hypoactive and hyperactive regions were positively correlated with activation of caudates. There was a positive correlation between hyperactive PFC and hypoactive regions.

CONCLUSIONSThe signal change of SMA is directly related to disease severity in early PD, and caudates may play a significant role in PD tactile processing. The hyperactivation of PFC may be not a compensation but a pathophysiological change related to PD neural dysfunction.

Aged ; Brain ; physiopathology ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Mechanoreceptors ; physiology ; Middle Aged ; Parkinson Disease ; physiopathology ; Severity of Illness Index ; Time Factors ; Touch ; physiology ; Touch Perception ; physiology

OBJECTIVE: To obtain normal data of quantitative sensory test (QST) in Korean adult. METHOD: The subjects were 85 normal adults aging from 30 to 69 years old, who had no abnormal sensory and neurologic problem. We performed following three QSTs on dominant side and one verbal questionnaire. 1) Semmes-Weinstein monofilament wire system (0.05 G, 0.2 G, 2 G, 4 G, 10 G, 300 G) for touch sensation, 2) Rydel-Seiffer Tuning Fork for vibration sensation, 3) TSA-2001 Thermal sensory analyser for thermal sensation, 4)University of Texas Subjective Peripheral Neuropathy verbal questionnaire. RESULTS: 1) Touch perception score measured with Semmes-Weinstein monofilament wire system, declined with age (p<0.01). 2) Vibration perception score measured with the tuning fork, declined with age in foot (p<0.01). 3) Warm sense and heat pain threshold measured with TSA-2001 thermal sensory analyser increased with age, and cold sense and cold pain threshold declined with age. 4) Weight showed negative correlation with vibration perception score in man's foot. CONCLUSION: Normal data of three sensory test obtained from this study could be used for the early detection of peripheral neuropathy or loss of "protective sensation".
Adult* ; Aged ; Aging ; Foot ; Hot Temperature ; Humans ; Pain Threshold ; Peripheral Nervous System Diseases ; Surveys and Questionnaires ; Sensation ; Texas ; Touch Perception ; Vibration