Assessing carpal tunnel syndrome with magnetoneurography. (July 2022)

• Record Type: Journal Article
• Authors: Sasaki, Toru; Kawabata, Shigenori; Hashimoto, Jun; Hoshino, Yuko; Sekihara, Kensuke; Adachi, Yoshiaki; Akaza, Miho; Fujita, Koji; Nimura, Akimoto; Yoshii, Toshitaka; Miyano, Yuki; Mitani, Yuki; Watanabe, Taishi; Sato, Shinji; Kim, Sukchan; Okawa, Atsushi
• Is Part Of: Clinical neurophysiology. Volume 139(2022)
• Page Start: 1
• Page End: 8
• Publication Date: 2022-07
• Subjects: Magnetoneurography -- Carpal tunnel syndrome -- Median nerve -- Digital nerve -- Conduction velocity -- Nerve conduction study; CSP common-mode subspace projection -- CTS carpal tunnel syndrome -- MNG magnetoneurography -- NCS nerve conduction study -- SQUID superconducting quantum interference device -- UGRENS unit gain constraint recursively applied null-steering spatial filtering; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2022.03.021
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Neural activity in carpal tunnel syndrome patients could be visualized using magnetoneurography. The lesion site could be visualized using the amplitude or nerve conduction velocity. Magnetoneurography could also visualize the improvement after surgery. Abstract: Objective: To measure the neuromagnetic fields of carpal tunnel syndrome patients after electrical digital nerve stimulation and evaluate median nerve function with high spatial resolution. Methods: A superconducting quantum interference device magnetometer system was used to record neuromagnetic fields at the carpal tunnel after electrical stimulation of the middle digital nerve in 10 hands of nine patients with carpal tunnel syndrome. The patients were diagnosed based on symptoms (numbness, tingling, and pain) supported by a positive Phalen or Tinel sign. A novel technique was applied to remove stimulus-induced artifacts, and current distributions were calculated using a spatial filter algorithm and superimposed on X-ray. Results: In 6 of the 10 hands, the amplitude of the inward current waveform attenuated to <70% or the nerve conduction velocity was <40 m/s. The results of conventional nerve conduction studies were normal for two of these six hands. All four hands that could not be diagnosed by magnetoneurography had severe carpal tunnel syndrome superimposed on peripheral neuropathy secondary to comorbidities. Conclusions: Technical improvements enabled magnetoneurography to noninvasively visualize the electrophysiological nerve activity in carpal tunnel syndrome patients. Significance: Magnetoneurography may have the potential to contribute to the detailed diagnosis of various peripheral nerve disorders.