Neurophysiological biomarkers for neurodegenerative disorders
The present disclosure provides methods for diagnosing and determining the disease progression of neurodegenerative disorders in patients using neurophysiological biomarkers.
1. A method for diagnosing a neurodegenerative disorder in a subject, the method comprising:
i) obtaining surface electromyographic (EMG) signal data from a pair of muscles in the subject at a specific frequency, wherein the EMG signal data comprises one EMG signal per each muscle at the specific frequency;
ii) processing the EMG signal data to determine an intermuscular coherence (IMC) phase of response between the pair of muscles at the specific frequency;
iii) repeating steps i) and ii) across a frequency range; and
iv) analyzing variability of the IMC phase of response between the pair of muscles across the frequency range to determine a phase variance value,
wherein the phase variance value is calculated as the standard deviation of an average phase difference between EMG signals per frequency across the frequency range, and
wherein the phase variance value indicates that the subject suffers from the neurodegenerative disorder.
2. The method of claim 1 , wherein the frequency range is about 5 Hz to about 80 Hz.
3. The method of claim 1 , wherein the phase variance value and an IMC value indicate that the subject suffers from the neurodegenerative disorder.
4. The method of claim 3 further comprising causing a display interface to display the phase variance value plotted against the IMC value.
5. The method of claim 4 , wherein the phase variance value of between about 0.2 to about 1.2 and the IMC value of equal to or less than about 0.023 indicates that the subject suffers from the neurodegenerative disorder.
6. The method of claim 4 , wherein the phase variance value of between about 0 to about 0.6 and the IMC value of greater than about 0.023 indicates that the subject does not suffer from the neurodegenerative disorder.
7. The method of claim 5 , wherein the phase variance value directly correlates to a severity of disease progression.
8. The method of claim 1 , wherein the neurodegenerative disorder is amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia, fronto-temporal dementia, or primary lateral sclerosis.
9. The method of claim 1 , wherein the pair of muscles includes arm muscles, hand muscles, leg muscles, or respiratory muscles.
10. The method of claim 9 , wherein the pair of arm muscles is a brachioradialis muscle and a bicep muscle.
11. The method of claim 1 further comprising causing a display interface to display a plot of the IMC phase of the response between the pair of muscles across the frequency range.
12. The method of claim 1 further comprising causing a display interface to display the phase variance value and an indication when the phase variance value exceeds a predetermined threshold value.