Diabetic Neuropathy refers to the condition where the nerves that take care of sensory functions in the body get damaged due to diabetes. Depending on where the damage occurs, neuropathy can be classified into four types:
- Peripheral neuropathy
- Autonomous neuropathy
- Focal neuropathy
- Proximal neuropathy
Of these, peripheral and autonomic neuropathies are the most frequently encountered. Peripheral neuropathy refers to damage in the extremities, mostly the foot and legs, while autonomic neuropathy refers to damage to nerves of the internal organs.
Peripheral Neuropathy affects the peripheral nerves, which are responsible for transmitting signals between the central nervous system and the rest of the body. Diagnosing peripheral neuropathy involves a combination of clinical evaluation, medical history, and various diagnostic tests.
Symptoms of peripheral neuropathy in the feet and legs include tingling, numbness, burning sensation, and pain. Diagnosis includes a thorough physical examination, medical history, and measurement of parameters such as vibration perception, and hot and cold perception. These values help evaluate the sensory status of the nerves. Biothesiometers are used to measure vibration perception threshold (VPT), an important indicator of sensory nerve function.
Kody Medical, the Chennai-based diabetic care equipment manufacturer, offers a range of digital biothesiometers such as BIOTHEZI-VPT, BIOTHEZI-VPT LITE, HCP-ELITE, and VPT ULTRA. The first two are lightweight economical models with manual control for the application of vibration. Vibration is applied to the foot of the patient from a low level and the value at which the patient starts to actually feel the vibration is noted. This is the vibration perception threshold of the patient. Based on the VPT values, the severity of peripheral neuropathy in the patient is determined.
HCP-ELITE is an instrument that helps determine the hot and cold perception thresholds of patients, along with the VPT. The instrument has a dual-colour display – red for the hot mode and green for the cool mode. The VPT ULTRA model helps determine VPT in larger nerve fibres and is used for vibration perception studies on both the hands and feet.
Sensory symptoms like pain, hyperesthesia, hyperalgesia and allodynia – that is contact pain are the first to appear. These occur due to abnormalities of C fibers, which are supposedly responsible for the early occurrence of symptoms.
Other somatic sensations of pressure, touch, vibration, and proprioception are likely as not, not affected at this stage. It is the warm, heat pain, cool and cool pain sensations that get affected first. Therefore, it makes more sense to detect HCP thresholds because they seem to be the first ones to get affected. HCP stands for Heat Cool and Pain
· The loss of nerve fiber in neuropathy is not uniform nor simultaneous.
· The damage to small thinly myelinated and unmyelinated nerve fiber is usually the beginning.
· This results in diminishing thermal and pain sensation along with autonomic decline.
· Sensitometer HCP helps detect Diabetic polyneuropathy at an early stage.
This is done by finding the raised or lowered thermal thresholds.
The Four Thresholds
Cool Detection threshold: ranging between 29 to 32 0C i.e. just below the neutral zone
Warm Detection threshold: ranging above neutral zone from 35 0C up to 38 0C
Heat Pain Detection threshold: ranging between 42 0C up to 45 0C
Cold Pain Detection threshold: ranging below 27 0C down to 27 0C
A neutral zone is around 32 0C to 34 0C
Absolute threshold is the transition point between no sensation to just the beginning of sensation. The cross-over point. Or a point at which one feels the sensation 50% of the time and no sensation 50% of the time. It is normally found by averaging several readings just above and below the threshold.
A vibratory perception threshold can be done with our device which measures vibratory sensation quantitatively. A probe was applied to the patient’s hand to explain the feel of vibration clearly. Then the patient is asked to concentrate on feet & tell as soon as he starts feeling the vibration and the value is noted. During recording, the voltage was increased from 0 to 50 volts. Grading of VPT was recorded as follows –
Normal VPT was from 0 to 15 volts,
Grade I was 16 to 25 volts and
26 to 50 volts was graded as grade II Diabetic large fiber neuropathy
Autonomic neuropathy, which involves damage to nerves of internal organs, affects 10–40% of hypertensive patients. Autonomic neuropathy can lead to problems with your heart rate and blood pressure, digestive system, bladder, sex organs, sweat glands, eyes, and the ability to sense hypoglycaemia.
KODYSCAN Cardiac Autonomic Neuropathy Analyzer helps determine parameters such as Heart Rate Variability (HRV), blood pressure analysis for a quantitative assessment of the Autonomic Nervous System (ANS), and Autonomic Balance (sympathetic and parasympathetic).
Heart rate variability (HRV) is an important non-invasive parameter that helps monitor autonomic dysfunctions. Computer analysis of HRV and other autonomic function assessments enable evaluation of the disease status in patients with diabetes.
A strong association exists between cardiovascular autonomic dysfunction and hypertension. Along with diabetes and heart disease, hypertension has contributed to the morbidities and mortalities in the general population.
Our Cardiac Autonomic Neuropathy analyser device provides the listed parameters.
i. Pulse rate/minute by palpatory method ( KODYS CAN using ECG signals for Pulse rate/minute)
ii. Postural Hypotension (Orthostatic) (Assessment of Blood Pressure)
iii. Sustained Handgrip (Assessment of Blood Pressure)
Heart rate variability (HRV) is one of the important non-invasive measures to monitor autonomic dysfunctions.
Judicious use of these instruments, along with a thorough clinical examination and medical history, can go a long way in the early diagnosis of diabetic neuropathy and improve the quality of life for patients.