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Year : 2021  |  Volume : 69  |  Issue : 1  |  Page : 147--148

Simple Indigenous Two-Point Discrimination Testing Device

Pawan Agarwal1, Prachir Mukati2, Rajeev Kukrele1, Dhananjaya Sharma2,  
1 Plastic Surgery Unit, Department of Surgery, NSCB Government Medical College, Jabalpur, Madhya Pradesh, India
2 Department of Surgery, NSCB Government Medical College, Jabalpur, Madhya Pradesh, India

Correspondence Address:
Pawan Agarwal
292/293, Napier Town, Jabalpur, 482001, Madhya Pradesh
India

Abstract

Background: Measurement of two-point discrimination (2-PD) is used in clinical practice to evaluate the severity of nerve injuries, neuropathy, and recovery of patients following nerve repair. Commercially available 2-PD testing devices are costly and therefore not available everywhere. Methods and Material: We made an economical indigenous 2-PD testing device from off-the-shelf components and tested its efficacy in volunteers. Statistical Analysis: The data were analyzed using Minitab Statistical Software Version 17.0 and Kappa statistics were used in the assessment of agreement between two devices. Results: A total of 30 (23 men, 7 women) subjects were included in the study. There was good agreement between the measurements of static 2-PD with the two different test devices: from fair (Kappa = 0.408, P = 0.018) to strong (Kappa = 0.618–0.795, P = 0.000). Conclusions: This device is simple to make, very economical, and obtains accurate 2-PD measurements.



How to cite this article:
Agarwal P, Mukati P, Kukrele R, Sharma D. Simple Indigenous Two-Point Discrimination Testing Device.Neurol India 2021;69:147-148


How to cite this URL:
Agarwal P, Mukati P, Kukrele R, Sharma D. Simple Indigenous Two-Point Discrimination Testing Device. Neurol India [serial online] 2021 [cited 2021 May 12 ];69:147-148
Available from: https://www.neurologyindia.com/text.asp?2021/69/1/147/310095


Full Text



The two-point discrimination (2-PD) test described by Weber is one of the most frequently used sensory tests and it reflects the sensory density of an area of skin.[1] The cost of commercially available devices and problems of using a reshaped paper clip[2] prompted us to design a 2-PD disc device made from off-the-shelf components. The efficacy of this device was tested and compared with paper clips in the present study.

 Material and Methods



This prospective, observational study of static 2-PD was conducted in a tertiary teaching hospital in central India on 30 normal volunteers. Patients with any conditions which might affect the ability to sense light touch were excluded.

The indigenous device was made from soft board and office pins. The soft board was cut in the shape of octagonal and rounded tip office pins were inserted at the edge of the soft board at a measured distance [Figure 1]. Rounded tips of paper clips were spaced at standard testing intervals from 1 mm to 8 mm apart.{Figure 1}

The radial and ulnar sides of the index and the middle finger of the dominant hand were tested. The test was done first using a calibrated paper clip and then using the indigenously made device. A standardized set of testing began at 8 mm and proceeded, to 2 mm distances. A total of three predetermined stimuli were used and the mean was recorded. The comparison was made for agreement between 2-PD values measured by a paper clip and a new indigenous disc device. The data were analyzed using Minitab (17.0) and Kappa statistics was used in the assessment of agreement between two devices.

 Result



A total of 30 (23 men, 7 women) subjects were included in the study. The mean age of the test subjects was 33 years (range: 24–50 years). There was good agreement between the measurements of static 2-PD with the two different test devices: from fair (Kappa = 0.408, P = 0.018;) to strong (Kappa = 0.618–0.795, P = 0.000) [Table 1].{Table 1}

 Discussion



2-PD is used in clinical practice to evaluate the severity of peripheral nerve injuries, neuropathy, recovery following nerve repair/transfer/decompression, recovery of sensation in skin graft/flaps, and in parietal lobe disorders.[3],[4],[5],[6] The most common testing “instrument” for 2PD is a compass or reshaped paper clip; which is easily available, economical, simple, quick and requires minimal training. However; measuring 2-PD with these two devices is not user-friendly with a lack of a standard procedure and precision. Paper clips need to bend in the appropriate shape, becomes greasy and slippery. It does not have a scale; therefore, it needs to be calibrated before each test. Its internal memory leads to variable inter-prong distance and has significant variation in its tip geometry. The same problems are faced by using compasses.[2]

These problems are not present in the aesthesiometer or the disk-criminator. However; they are not easily available. The drawbacks of aesthesiometer are sharp tips that may cause pain; repeated change in the setting of the inter-prong distance is time-consuming, alters the rhythm of the test and gives cues to the patient as to what the next stimulus may be.[2] The disk-criminator permits a steady testing sequence with ease of rotation of the disk between one- and two-prong stimuli. The other advantage of disc-criminator is a measurement of moving 2-PD can be done.

The commercially available disk Discriminator costs 4,000–6,000 INR and therefore not available everywhere. Our indigenous device is inexpensive (cost: INR 100 only), can be easily made by off-the-shelf material, does not require any training to use and gives similar accuracy as modified paper clips.

 Conclusion



Our indigenous 2-PD disc device, made from off-the-shelf components is simple to make, inexpensive, user-friendly, and comparable to the paper clip for 2-PD testing.

Acknowledgment

We acknowledge the statistical analysis by P Kiran Rao, MBA, PGDC (clinical research) Assistant Manager Operations, Apollo Rajshree Hospital, Indore (MP) India.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1E.H. Weber, on the Tactile Senses. Edited by Ross HE, Murray DJ. 2nd Edition. Hove (UK): Taylor & Francis; 1834.
2Crosby PM, Dellon AL. Comparison of two-point discrimination testing devices. Microsurgery 1989;10:134-7.
3Shooter D. Use of two-point discrimination as a nerve repair assessment tool: Preliminary report. ANZ J Surg 2005;75:866-8.
4Agarwal P, Shukla P, Sharma D. Saphenous nerve transfer: A new approach to restore sensation of sole. J Plast Reconstr Aesthet Surg 2018;71:1704-10.
5Agarwal P, Sharma B, Sharma D. Tarsal tunnel release restores sensations in sole for diabetic sensorimotor polyneuropathy. JCOT article in press https://doi.org/10.1016/j.jcot. 2019.08.014
6Misra UK, Kalita J, Mittal BR, Das BK. Cortical sensory loss: is it always cortical? Neurol India 1997;45:101-4.