Prevalence and Clinical Associations of A-Waves in Routine Nerve Conduction Studies: A Retrospective Analysis

Area of Science:

• Neurophysiology
• Clinical Electrophysiology
• Neurology

Background:

• A-waves are late responses observed during motor nerve conduction studies (NCSs).
• Their prevalence and clinical associations in routine NCS evaluations are not well-defined.
• Understanding A-wave characteristics is crucial for interpreting NCS findings in neurological conditions.

Purpose of the Study:

• To determine the prevalence of A-waves in a cohort undergoing routine NCS.
• To investigate the clinical associations and diagnostic implications of A-waves.
• To explore A-wave presence in patients with normal NCS findings and various neuropathies.

Main Methods:

• Retrospective analysis of medical and electrophysiological data from 456 patients.
• Inclusion of 1197 nerves from 404 patients evaluated for routine NCS and F-wave studies.
• Data collected between January 2022 and December 2022 by a single examiner.

Main Results:

• A-waves were observed in 42.2% of individuals, including those with normal NCSs.
• A-waves were most prevalent in polyneuropathies, motor neuron disorders, radiculopathy, and myopathy.
• A-waves were more common in tibial nerves and older subjects, and frequently seen in normal NCSs (78/185 cases).

Conclusions:

• A-waves are frequently detected in subjects with normal NCSs, other than multiple A-waves.
• This study is the first to report A-waves in myopathy and neuromuscular junction disorders, though findings require cautious interpretation.
• A-waves provide valuable insights into nerve conduction abnormalities across a spectrum of neurological conditions.