Using a Neurothesiometer in Diabetic Foot Assessment

An Essential Tool for Neuropathy Detection

Introduction

Diabetic foot complications are a significant concern in individuals with diabetes mellitus, often leading to severe consequences such as ulcers or even amputations. One of the primary contributors to these complications is diabetic peripheral neuropathy (DPN), a condition characterized by nerve damage caused by prolonged high blood sugar levels. Early detection of neuropathy is essential to prevent the progression of foot-related complications. The neurothesiometer, a diagnostic device, plays a pivotal role in assessing vibration perception thresholds (VPT) and is considered a reliable method for detecting neuropathy in diabetic patients.

What is a Neurothesiometer?

A neurothesiometer is a handheld device designed to measure vibration perception thresholds in patients. It consists of a probe that generates controlled vibrations of varying intensities, usually measured in volts. The device is applied to specific points on a patient’s skin, typically the soles of the feet or the big toe, to determine their sensitivity to vibrations.

How it Works

- The device delivers vibrations at adjustable intensities.

- These vibrations are gradually increased while the patient indicates when they first feel the sensation.

- The voltage reading at which the patient perceives the vibration is recorded as their vibration perception threshold.

Importance in Diabetic Foot Assessment

Peripheral neuropathy often diminishes a patient’s ability to sense vibrations, making them more susceptible to injuries and ulcers. The neurothesiometer provides an objective and quantifiable way to assess this sensory loss, enabling healthcare professionals to identify neuropathy at an early stage.

Benefits of Using a Neurothesiometer

·       Non-invasive: The test is painless and does not require any surgical or invasive procedures.

·       Quick and Efficient: The assessment takes only a few minutes per patient.

·       Quantifiable Results: The device offers precise measurements, aiding in tracking disease progression.

·       Preventive Potential: Early detection allows for timely interventions to manage or slow the progression of neuropathy.

Procedure for Using a Neurothesiometer

The neurothesiometer is straightforward to use, but specific steps must be followed to ensure accurate results:

Preparation

1. Ensure the device is calibrated and functioning correctly.

2. Explain the procedure to the patient to ensure cooperation and understanding.

3. Place the patient in a comfortable position with their feet properly exposed and clean.

Testing Process

1. Apply the neurothesiometer probe to the designated area, typically the big toe or the ball of the foot. Take care not to press the probe against the skin, it should rest against the skin surface.

2. Gradually increase the vibration intensity while instructing the patient to indicate when they first feel the sensation.

3. Record the voltage at the point of sensation awareness.

4. Repeat the process on both feet for comparison.

Interpreting Results

- A higher vibration perception threshold indicates reduced sensitivity, suggesting the presence of neuropathy.

- Patients with a VPT <15 V had a cumulative incidence of foot ulceration of 2.9% compared with 19.8% in patients with a VPT >25 V (Matthew J Young, John L Breddy, Aristidis Veves, Andrew J M Boulton; The Prediction of Diabetic Neuropathic Foot Ulceration Using Vibration Perception Thresholds: A prospective study. Diabetes Care 1 June 1994; 17 (6): 557–560. https://doi.org/10.2337/diacare.17.6.557)

Applications in Clinical Practice

The neurothesiometer is widely used in various healthcare settings, from primary care clinics to specialised diabetic foot clinics. Its primary applications include:

Screening for Neuropathy

Routine use of the neurothesiometer during annual diabetic check-ups helps identify patients at risk of developing foot ulcers.

Monitoring Disease Progression

By tracking changes in vibration perception thresholds over time, clinicians can assess the effectiveness of interventions and adjust treatment plans.

Risk Stratification

Patients with higher vibration perception thresholds may be categorized as high-risk and prioritised for preventive care, such as footwear modifications or specialised podiatric services.

Limitations and Considerations

While the neurothesiometer is an invaluable tool, it is essential to recognize its limitations:

- Subjectivity: The results depend on the patient’s ability to communicate their perception, which may vary.

- Operator Dependency: Accurate results require proper technique and consistent testing methods.

- Cost: The device may not be readily available in resource-limited settings.

Conclusion

The neurothesiometer is a useful instrument in the early detection and management of diabetic peripheral neuropathy. It is also used in research establishments working with new technologies in diabetic foot medicine.