V. B. Narayanamurthy

Bio: V. B. Narayanamurthy is an academic researcher from Sundaram Medical Foundation. The author has contributed to research in topics: Vibration perception. The author has an hindex of 2, co-authored 2 publications receiving 25 citations.

Correlation between two-point discrimination with other measures of sensory loss in diabetes mellitus patients

Abstract: Diabetic neuropathy is one of the most important factors for foot ulceration in diabetes mellitus (DM) patients. Among different sensibility measures of neuropathy, two-point discrimination (TPD) has been suggested as a reliable method; however, the correlation of TPD with other well-known measures is not known. We measured the loss of protective sensation using Semmes-Weinstein Monofilaments (SWMF), hardness of the foot sole using shore meter (sh), power ratio (PR) using pedopowergraph and TPD using esthesiometer in foot areas of both left and right legs in 14 DM subjects. We have found no correlation either between TPD and shore values (sh) or between TPD and PR. The SWMF (10 g) is found not to provide any additional value in measuring loss of sensation in comparison to TPD. The TPD appears to be measuring different property of the foot compared to other measures. The mechanism of this independence is not well understood and more investigation is required to understand the mechanism.

Peripheral neuropathy induced by drinking water contaminated with low-dose arsenic in Myanmar

Abstract: More than 140 million people drink arsenic-contaminated groundwater. It is unknown how much arsenic exposure is necessary to cause neurological impairment. Here, we evaluate the relationship between neurological impairments and the arsenic concentration in drinking water (ACDW). A cross-sectional study design was employed. We performed medical examinations of 1867 residents in seven villages in the Thabaung township in Myanmar. Medical examinations consisted of interviews regarding subjective neurological symptoms and objective neurological examinations of sensory disturbances. For subjective neurological symptoms, we ascertained the presence or absence of defects in smell, vision, taste, and hearing; the feeling of weakness; and chronic numbness or pain. For objective sensory disturbances, we examined defects in pain sensation, vibration sensation, and two-point discrimination. We analyzed the relationship between the subjective symptoms, objective sensory disturbances, and ACDW. Residents with ACDW ≥ 10 parts per billion (ppb) had experienced a “feeling of weakness” and “chronic numbness or pain” significantly more often than those with ACDW 50 ppb). These data suggest a threshold for the occurrence of peripheral neuropathy due to arsenic exposure, and indicate that the arsenic concentration in drinking water should be less than 10 ppb to ensure human health.

Two-point discrimination in diabetic patients (糖尿病患者的两点辨别力)

Abstract: Background Diabetes mellitus (DM) is a common cause of polyneuropathy. The aim of the present study was to evaluate two-point discrimination (TPD) compared with nerve conduction studies in the early stages of DM. Methods Forty-eight patients with early diagnosed (<5 years) type 2 DM and 17 healthy controls were evaluated. Of the patients with DM, 26 had neuropathic pain and 22 were asymptomatic. TPD and electrophysiological evaluations was obtained for all subjects. Results Nerve conduction studies in patients showed findings related to both demyelination and axonal damage. Patients with neuropathic pain had higher TPD values on the plantar surface of the foot and both groups of DM patients had higher TPD values on the outer lateral malleolus compared with the control group (P < 0.05). There was a correlation between TPD and axonal damage in patients with neuropathic pain (P < 0.05). In patients without neuropathic pain, there was a correlation between TPD values and distal latencies of motor or sensory nerves (P < 0.05). In the control group, only third digit TPD values were related to the distal motor latency of the median nerve (P < 0.05). Conclusion In conclusion, the TPD method is a less painful, practical, costeffective, and more easily applicable method that was completed in less timethan nerve conduction studies. Higher TPD values in the lower extremities indicate nerve damage in patients. These findings suggest that increased TPD values can easily determine neuropathy starting in the early stages of diabetes in patients with DM. 摘要 背景 糖尿病是多发性神经病变最常见的病因之一。本研究的目的是在处于早期阶段的糖尿病患者中比较测定两点辨别力（two-point discrimination, TPD）与神经传导研究。 方法 评估了48名早期（< 5年）诊断的2型糖尿病患者以及17名健康对照者。在糖尿病患者中，26名患者有神经性疼痛，22名患者无症状。所有的受试者都要进行TPD与电生理学评估。 结果 患者的神经传导研究结果显示与脱髓鞘以及轴突损害都有关系。与对照组相比较，有神经性疼痛的患者足底面的TPD值更高，并且两组糖尿病患者外踝面的TPD值都更高（P < 0.05）。在有神经性疼痛的患者中，TPD与轴突损害具有相关性（P < 0.05）。在没有神经性疼痛的患者中，TPD值与运动或者感觉神经的远端潜伏期具有相关性（P < 0.05）。在对照组中，只有第三指的TPD值与正中神经的远端运动潜伏期具有相关性（P < 0.05）。 结论 总之，与神经传导研究相比较，测定TPD的方法是一种痛苦少、成本效益高、更容易施行的方法，并且可以在更短的时间内完成。患者下肢TPD值更高意味着神经损害。这些研究结果提示，在处于早期阶段的糖尿病患者中，从升高的TPD值可以很容易地判定是否有神经病变。

Sensory changes after tongue reduction for macroglossia.

Abstract: We report sensory changes after tongue reduction by the Harada-Enomoto method for macroglossia in a 20-year-old woman with Beckwith-Wiedemann syndrome. Sensory tests were performed before surgery and 1 week and 2 months after surgery. We assessed the static tactile threshold, vibration sense, static 2-point discrimination, pain threshold, and taste. No sensory loss of any category tested was observed after tongue reduction.