Diabetes mellitus (DM) is a syndrome of disorders characterized by hyperglycemia caused due to a relative or absolute deficiency of insulin, decreased glucose utilization, increased gluconeogenesis [1]. Diabetes mellitus is a global health problem, affecting more than 170 million individuals and all age groups worldwide. In more developed societies, the prevalence of diabetes mellitus has reached about 6 % [2]. Diabetes is defined as a state of chronic hyperglycemia and is classified into two major types, type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Type 1 diabetes mellitus is due to total failure of the pancreas to secrete insulin, autoimmune destruction of insulin-secreting cells in the islets of Langerhans and is also known as Insulin Dependent Diabetes mellitus (IDDM).

Type 2 DM or Non-Insulin Dependent Diabetes mellitus (NIDDM) is a heterogeneous, multifactorial, polygenic disease characterized by insulin secretion defects. It is associated with insulin resistance and qualitative and quantitative insulin deficiency caused by alterations in several gene products [3-4]. The presence of DM predisposes to increased risk of many complications such as cardiovascular diseases, peripheral vascular diseases, stroke, neuropathy, renal failure, retinopathy and blindness. Complications of Diabetes may be classified into macrovascular (coronary heart disease, cerebrovascular disease and peripheral vascular disease) and microvascular (retinopathy, nephropathy and neuropathy). The physiological properties of nerves and muscles are usually modified due to pathophysiological changes occurring from many diseases like diabetes.

Diabetes is fast becoming the epidemic of the 21^st century [5-6]. The physiological properties of nerves and muscles are usually modified due to pathophysiological changes resulting from many diseases like diabetes [7]. The number of people with diabetes has risen from 108 million in 1980 to 422 million in 2014. The global prevalence of diabetes among adults over 18 years has been increased from 4.7% in 1980 to 8.5% in 2014. Diabetes prevalence has been rising more rapidly in the middle- and low-income countries [8-10]. A healthy diet, regular physical activity, maintaining average body weight and avoiding tobacco use prevent or delay the onset of type 2 diabetes.

NCS/EMG establishes diagnosis quite early than other diagnostic procedures because of its sensitivity to detect the slowing of conduction of action potential in a nerve, which is an early indicator of peripheral neuropathy. Neurophysiologic studies supplemented the clinical examination by precisely localizing the lesion and characterizing the conduction abnormalities providing additional information, details and objectivity. They delineate a variety of conditions that may otherwise escape detection [19]. Primarily NCS determination is used compared to EMG to study diabetic neuropathy since it is non-invasive, can easily be reproduced, and is sensitive, which gives a clear recording with minimal disturbances. Early functional impairment of nerve in asymptomatic cases can be studied, i.e. disorder affecting the nerves is insufficient to produce clinical abnormality may be detected as a decrease in Sensory nerve conduction velocity. It is helpful as a diagnostic tool, prognostic and follows up the study of neuropathy [20]. Based on this background, we aimed to evaluate the comparative peripheral nerve conduction study of median and ulnar nerves in people with type-2 diabetes with symptoms of polyneuropathy with age and sex-matched normal subjects.

Settings: This study was conducted in the Department of Physiology and Medicine at JJM Medical college and Hospital, Davanagere, Karnataka.

Duration and Type of the Study: This is a case-control study conducted from April 2015-Nov 2019.

Sampling Methods: A total of 29 patients diagnosed with type 2 diabetes mellitus as per American Diabetes Association (ADA) criteria [21] attended to general medicine OPD atJJMMedicalcollege and hospital, Davanagere, Karnataka and also we included29 healthy volunteers (age and sex-matched) as controls.

Sample Size: Total 58 Subjects, 29 Cases and 29 Controls.

Inclusion Criteria: All the subjects aged between 30 to 70 years and patients diagnosed with type 2 Diabetes Mellitus with symptoms of polyneuropathy were included in the present study.

Exclusion Criteria: subjects whoever suffering from Type1 Diabetes Mellitus, Nephropathy, Kidney, Liver and Thyroid diseases, Urinary Tract Infections,

Median sensory nerve conduction: The recording electrode for orthodromic conduction is placed 3 cm proximal to the distal crease, and reference is placed at a distance of 3 cm proximally. For stimulation, ring electrodes are placed at the second or third digits. The cathode is placed at the first interphalangeal joint and anode 3 cm distal.

Ulnar sensory nerve conduction: The orthodromic conduction was done by stimulating the digital nerve by ring electrodes at the interphalangeal joint of the fifth digit.

Ethical Consideration and Permission: All the subjects were included after taking informed consent and approved by Institutional Ethics Committee (IEC).

Statistical analysis: The data were analyzed for the difference in the right and left median, and Ulnar Nerves Latency, Amplitude, CV and F minimum latency between cases and controls was analyzed using unpaired students T-Test. Statistical analysis was performed by using Microsoft Excel Spread Sheets. A p-Value <0.05 was considered statistically significant.

Figure 1- Shows the Mean values of Rt. & Lt Median motor nerve conduction.

Figure 1: Shows the right and left median motor nerve conduction in study subjects. There was a reduced amplitude, CV, and increased latency, and minimum latency was observed in cases compared to controls.

Figure 2: Shows the right and left ulnar motor nerve conduction in between cases and controls. A mild increase in motor latency was observed in both right and left ulnar nerve motor conduction in patients with type 2 diabetes mellitus with polyneuropathy compared to healthy controls. There is no change in Amplitude and CV in both right and left ulnar nerve conduction.

The NCV is gradually diminished by Diabetic Neuropathy, with an estimate of a loss of approximately 0.5m/s/year. A simple rule is that a 1% decrease in HbA1c improves the conduction velocity of about 1.3m/s (Arezzo,1997). Hyperglycemia correction in patients results in improvement of symptoms and nerve conduction abnormalities (Judzewitsch et al.,1983). Elizabeth et al. studied the neuropathy assessment in diabetic patients by analyzing the conduction velocity within the motor and sensory fibres. They concluded that the longer the duration of diabetes, certainty of changes in the motor and sensory responses of the individual is more. These studies were consistent with a previous similar survey done by Muthuselvi K et al. where the amplitude values of both sensory and motor nerve conduction studies were found to be significantly reduced in diabetic individuals than the non-diabetic control group with a significant' p' value. It was also seen that there was an inverse relationship on correlating the blood sugar values, with increasing blood sugar values, sensory nerve conduction velocities are correspondingly decreasing, and motor nerve conduction velocities reducing. However, there are some fluctuations [23-24]. But, in our study, the correlation of cases with blood sugars was not considered, although all the patients in our study mostly presented with blood sugar and higher HbA1c levels. These studies findings were also consistent with the previous study done by Olney, Richard K. The present study was comparable to the study done by Verma et al., who showed that amplitude and conduction velocity range is significantly decreased in diabetic patients in comparison to normal healthy volunteers, [25]. and the most affected nerve in the upper limb is the Median nerve, and the lower limb is a sural nerve which is also comparable with a study done by Zahed Ali et.al.[26]. The values of the F-wave parameters, which were recorded from the median and the ulnar nerves, were following those reported [27-29]. A study done by Xuan Kong et al. demonstrated that NCS did use computer-based electrodiagnostic equipment was a better tool for the diagnosis of Diabetic Polyneuropathy [30].

From our study, we conclude that increased distal motor latencies, the reduced amplitude of CMAP and motor conduction velocities in the Median nerve indicate involvement more of the median nerve in the cases referred compared to the age and sex-matched normal subjects.