A quantitative skin impedance test to diagnose spinal cord injury

Eur Spine J, 2009 · DOI: 10.1007/s00586-009-0896-x · Published: March 20, 2009

Spinal Cord Injury Neurology Dermatology

Simple Explanation

This study explores using skin impedance measurements to diagnose spinal cord injuries, especially in patients who are unconscious or unable to cooperate during traditional neurological exams. Skin impedance was measured at sensory key points (dermatomes) in both SCI patients and a control group. An artificial neural network (ANN) was then used to analyze and classify these impedance values. The ANN was able to classify traumatic SCI patients with a success rate of 73%, suggesting that skin impedance testing could be a simple, objective, and non-invasive method for assessing SCI.

Study Duration

Not specified

Participants

15 traumatic SCI patients (13 paraplegics and 2 tetraplegics) and 15 control subjects

Evidence Level

Not specified

Key Findings

1
The artificial neural network (ANN) could classify traumatic SCI patients with a success rate of 73% when using skin impedance values.
2
Paraplegic patients showed an increasing inclination in skin impedance from the level of the SCI to the lower part of the body, while tetraplegic patients showed slight impedance value changes throughout all dermatomes.
3
Using AC current with a frequency of 200 Hz provided an accurate value of skin resistance, reducing errors in calculating the real skin resistance with respect to the measured value.

Research Summary

The study aimed to develop a quantitative skin impedance test to diagnose spinal cord injury (SCI), particularly in unconscious or non-cooperative patients. Skin impedance measurements were taken at sensory key points in 15 SCI patients and 15 control subjects. An artificial neural network (ANN) was employed to classify the impedance values. The ANN achieved a 73% success rate in classifying traumatic SCI patients, suggesting the proposed method could be a simple, objective, non-invasive, and inexpensive way to assess SCI.

Practical Implications

Diagnostic Tool

Skin impedance testing could serve as a diagnostic tool for SCI, especially in patients who cannot undergo traditional neurological examinations.

Objective Assessment

The quantitative nature of the test offers a more objective assessment of SCI compared to subjective clinical neurological examinations.

Monitoring Tool

The technique may be used for monitoring and research purposes to ﬁnd out any natural and/or interventional recovery or deterioration in SCI.

Study Limitations

1
The number of tetraplegic subjects was small, which may have affected the ANN's learning phase and overall accuracy.
2
Several factors such as environmental temperature, wetness, perspiration, and skin preparation can affect skin impedance measurements.
3
It is not well known whether the change occurred in the superﬁcial skin or deeper tissues yet.

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