Far-Infrared Socks for Neuropathic Pain and Nerve Function in Diabetic Patients

The Leeds Neuropathic Symptoms and Signs Assessment Scale (LANSS) was developed by Bennett (2001) and its Turkish validity and reliability study was conducted by Yücel et al. (2004). It is used clinically to differentiate neuropathic pain from nociceptive pain and consists of a five-item pain questionnaire (max: 16 points) and a two-item sensory assessment (max: 24 points). The pain questionnaire evaluates symptoms like tingling, paresthesia, skin color changes, electric shock sensations, and burning pain. The sensory section includes Allodynia and Pinprick tests; in the Allodynia test, a cotton wisp is applied to painful and non-painful areas-if discomfort is reported in the affected region, allodynia is considered present. If the total score is ≥12, pain is classified as neuropathic, while a score <12 indicates nociceptive pain. The scale has 82-91% sensitivity and 80-94% specificity when compared to clinical diagnosis.

The Neuropathic Pain Impact on Quality of Life Questionnaire (NePIQoL) was developed by Poole et al. (2009) to assess the impact of neuropathic pain on quality of life. The Turkish validity and reliability study was conducted by Acar et al. (2016) (Acar et al., 2016; Poole et al., 2009). In the original study, the internal consistency of the total NePIQoL was reported as 0.86, while in the validity and reliability study, it was found to be 0.99. The scale consists of five subdimensions: pain and other symptoms, relationships, daily activities, emotional impact of pain, and personal/self-care. It is a 42-item, 5-point Likert-type scale. The minimum possible score on the questionnaire is 42, while the maximum is 210. A score closer to 210 indicates a greater negative impact of neuropathic pain on quality of life. Conversely, lower scores reflect a better quality of life with less impact from neuropathic pain.

Electroneuromyography (ENMG) assesses nerve, muscle, and motor neuron functions by converting electrical signals into interpretable data (Rabbi et al., 2019). Used in diabetic patients for over 50 years, ENMG evaluates compound muscle action potential (CMAP) and sensory nerve action potential (SNAP), mainly for diabetic neuropathy (Najafi et al., 2018). This study will assess motor conduction in the lower extremities by recording from the abductor hallucis and extensor digitorum brevis muscles via tibial and common peroneal nerve stimulation, measuring distal latency, CMAP amplitude, and conduction velocity. Sensory conduction will be tested by stimulating sural nerves 12 cm proximally from the lateral malleolus using surface (motor) and ring (sensory) electrodes (Erbas et al., 2011; Ovayolu et al., 2008; Sarılar & Gök, 2021). ENMG will be performed at room temperature with a Medelec Synergy EMG system, ensuring skin temperature >31°C, at baseline and three months later.

Clothing comfort is crucial for both manufacturers and users (Bertaux et al., 2010), with garments needing to avoid discomfort. Comfort involves various sensory aspects: visual (aesthetic), thermal (cold/heat), pain (tingling/itching), and tactile (smooth/rough, soft/hard) (Malik & Sinha, 2012; Soroka et al., 2019). Studies use objective methods (Herbaut et al., 2016; Teyeme et al., 2021) and subjective scales (Matthias et al., 2021; Mills et al., 2011). We will assess sock comfort using a Visual Analog Scale (VAS), ranging from "Very Comfortable" (10) to "Very Uncomfortable" (0). The VAS will be collected at each follow-up, with prior instructions given. Participants will consider visual, thermal, pain, and tactile properties while rating their experience.