Improving neurophysiological biomarkers for functional myoclonic movements

Area of Science:

• Neuroscience
• Clinical Neurology
• Biomarkers

Background:

• Differentiating functional jerks (FJ) from organic myoclonus presents diagnostic challenges.
• The Bereitschaftspotential (BP) is an existing biomarker for FJ, but its sensitivity and subjectivity limit its clinical utility.
• Event-related desynchronization (ERD) in the beta band has emerged as a potential complementary marker for FJ.

Purpose of the Study:

• To evaluate the diagnostic value of combining ERD with quantitative BP analysis in clinical practice for differentiating FJ from cortical myoclonus (CM).
• To assess the diagnostic gain, sensitivity, and specificity of individual and combined biomarkers.

Main Methods:

• Included 29 patients with FJ and 16 patients with CM.
• Utilized jerk-locked back-averaging for classical and quantified BP determination.
• Employed time-frequency decomposition for ERD analysis in the broad beta range (13-45 Hz).

Main Results:

• ERD in the beta band was significantly higher in FJ patients compared to CM patients (p < 0.001).
• Combining ERD with classical BP yielded an additional 53% diagnostic gain.
• Integrating ERD with both quantitative and classical BP achieved a 71% additional diagnostic gain without compromising specificity.

Conclusions:

• The study proposes using combined beta ERD assessment and quantitative BP analysis for patients with suspected FJ, particularly when the classical BP is negative.
• This combined approach offers improved diagnostic accuracy for functional jerks.