Research has suggested that altering the perceived shape and size of the body image significantly affects perception of somatic events. The current study investigated how multisensory illusions applied to the body altered tactile perception using the somatic signal detection task. Thirty-one healthy volunteers were asked to report the presence or absence of near-threshold tactile stimuli delivered to the index finger under three multisensory illusion conditions: stretched finger, shrunken finger and detached finger, as well as a veridical baseline condition. Both stretching and shrinking the stimulated finger enhanced correct touch detections; however, the mechanisms underlying this increase were found to be different. In contrast, the detached appearance reduced false touch reports-possibly due to reduced tactile noise, as a result of attention being directed to the tip of the finger only. These findings suggest that distorted representations of the body could have different modulatory effects on attention to touch and provide a link between perceived body representation and somatosensory decision-making.
It has been postulated that subjects with high levels of oral sensory perception and motor ability are able to achieve higher standards of oral hygiene even under different dietary regimes. In this study, eleven dental personnel volunteers were started on a low-sucrose diet for one week, followed by a high-sucrose diet for another week, while eleven others followed a reverse-order dietary regime. Oral sensory perception and motor ability were assessed by the oral stereognosis test and a test for oral motor ability. There was a greater trend for subjects to have more plaque on their teeth when they were on the high-sucrose diet, even when normal oral hygiene procedures were taken. There were no significant correlations between the state of oral hygiene and levels of oral sensory perception and motor ability. These results do not support the hypothesis that subjects with high levels of oral sensory perception and motor ability are likely to achieve better oral hygiene.
The purpose of this paper is to clarify the reference vibrotactile perception thresholds (VPT) for healthy people in Malaysia. The measurement equipment standard, ISO 13091-1, of the vibrotactile perception thresholds for the assessment of nerve dysfunction and the analysis and interpretation of measurements at the fingertips standard, ISO 13091-2, were published in ISO/TC108/SC4/WG8 on 2001 and 2003 individually. In the ISO 13091-2 standard, the reference VPT data were obtained from few research papers. Malaysian people's VPT data don't include to this standard. In Malaysia, when the VPT is using to diagnose of the hand-arm vibration syndrome, the reference VPT data need to compare with the worker's ones. But, Malaysia does not have the reference VPT data yet. So, in this paper, the VPT was measured by using ISO 13091-1 standard equipment to obtain the reference data for Malaysian people. And these data were compared with the ISO reference data on the ISO 13091-2 standard. From the comparison of these data, it was clear that the Malaysian healthy people's VPT data were consistent with the reference data of the ISO 13091-2 standard.
A cross sectional study was conducted to investigate the effects of pesticide exposure (organophosphate and carbamate) using nerve conductive velocity, current perception threshold (CPT). Cluster random sampling was employed to recruit 64 paddy farmers and 22 fishermen in June 2006. The duration of pesticide exposure was between (5-20) years. The CPT values were measured using Neurometer CPT/Eagle, on the index finger and the great toe with three neuroselective frequencies range (2000, 250, and 5 Hz). The results showed that at the three different frequencies, the CPT values were significantly elevated among farmers on both the medial and peroneal nerves (P < .002). The measurement of CPT can be used as a biomarker to determine and monitor the effects of organophosphate and carbamate exposure among workers who may have been exposed.
PURPOSE: To determine the influence of age and gender on macular sensitivity to light in healthy subjects of 4 age groups using the MP-1 microperimeter.
METHODS: A prospective study was carried out on 50 healthy subjects (age range: 18-60 years) divided into 4 age groups; 18-30 years, 31-40 years, 41-50 years and 51-60 years. Full-threshold microperimetry of the central 10° of retina was performed utilizing 32 points with the MP-1. Macula area was divided into four quadrants, which were superior nasal (SN), inferior nasal (IN), inferior temporal (IT) and superior temporal (ST).
RESULTS: Total mean sensitivity at 10° for age groups 18-30 years, 31-40 years, 41-50 years and 51-60 years were 19.46 ± 0.30, 19.40 ± 0.39, 19.47 ± 0.35 and 18.73 ± 0.75 (dB), respectively. There was a significant difference in total mean retinal sensitivity at 10° and at the four quadrants with age but not for gender. The retinal sensitivity was highest in the IT quadrant and lowest in the SN quadrant for all age groups. The linear regression analysis revealed that there was a 0.019 dB, 0.016 dB, 0.022 dB, 0.029 dB and 0.029 dB per year age-related decline in mean macular sensitivity within the central 10° diameter in the SN, IN, IT and ST quadrants respectively.
CONCLUSION: Among normal healthy subjects, there was a linear decline in retinal light sensitivity with increasing age with the highest reduction in the superior nasal quadrant and lowest in the inferior temporal quadrant.