Concentric Needle Jitter Measurements in Voluntarily Activated Deltoid Muscle in Healthy Control Subjects.

Area of Science:

• Neurology
• Electromyography
• Muscle Physiology

Background:

• The deltoid muscle is sensitive to neuromuscular abnormalities.
• Normative data for single-fiber electromyography (concentric needle jitter) in the deltoid muscle is currently unavailable.
• This gap hinders accurate diagnosis of conditions like myasthenia gravis.

Purpose of the Study:

• To establish normative electrophysiological data for concentric needle jitter in the deltoid muscle.
• To define reference values for mean consecutive difference (MCD) in healthy adults.
• To provide a baseline for diagnosing neuromuscular junction disorders affecting the deltoid muscle.

Main Methods:

• Assessed jitter using mean consecutive difference (MCD) in the voluntarily activated deltoid muscle of 32 healthy adults.
• Calculated the mean MCD of 20 pairs for each subject.
• Determined overall and individual jitter reference values (outliers) based on pooled data.

Main Results:

• Mean MCD values were 21.15 ± 3.42 μs for men and 19.50 ± 2.34 μs for women.
• Individual jitter reference (outlier) values were 27.84 ± 4.68 μs for men and 25.42 ± 3.19 μs for women.
• No prior deltoid muscle jitter values exist for comparison.

Conclusions:

• Proposed normal mean MCD reference values: <28 μs for men and <26 μs for women.
• Proposed normal outlier limits: <38 μs for men and <32 μs for women.
• These values provide essential benchmarks for clinical electrodiagnostic assessments.