Details

Autor(en) / Beteiligte

• Szelényi, Andrea
• Fava, Enrica

Titel

Long latency responses in tongue muscle elicited by various stimulation sites in anesthetized humans – New insights into tongue-related brainstem reflexes

Ist Teil von

• Brain stimulation, 2022-05, Vol.15 (3), p.566-575

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Electronic Journals Library - Freely accessible e-journals

Beschreibungen/Notizen

• Long Latency Responses (LLR) in tongue muscles are a scarcely described phenomenon, the physiology of which is uncertain. The aim of this exploratory, observational study was to describe tongue-LLR elicited by direct trigeminal nerve (DTNS), dorsal column (DoColS), transcranial electric (TES) and peripheral median nerve (MNS) stimulation in a total of 93 patients undergoing neurosurgical procedures under general anesthesia. Bilateral tongue responses were derived concurrently after each of the following stimulations: (1) DTNS applied with single monophasic or train-of-three pulses, ≤5 mA; (2) DoColS applied with a train-of-three pulses, ≤10 mA; (3) TES consisting of an anodal train-of-five stimulation, ≤250 mA; (4) MNS at wrist consisting of single or train-of-three monophasic pulses, ≤50 mA. Polyphasic tongue muscle responses exceeding the latencies of tongue compound muscle action potentials or motor evoked potentials were classified as LLR. Tongue-LLR were evoked from all stimulation sites, with latencies as follows: (1) DTNS: solely ipsilateral 20.2 ± 3.3 msec; (2) DoColS: ipsilateral 25.9 ± 1.6 msec, contralateral 25.1 ± 4.2 msec; (3) TES: contralateral 55.3 ± 10.2 msec, ipsilateral 54.9 ± 12.0 msec; (4) MNS: ipsilateral 37.8 ± 4.7 msec and contralateral 40.3 ± 3.5 msec. The tongue muscles are a common efferent in brainstem pathways targeted by trigeminal and cervical sensory fibers. DTNS can elicit the “trigemino-hypoglossal-reflex”. For the MNS elicited tongue-LLR, we propose the term “somatosensory-evoked tongue-reflex”. Although the origin of the TES related tongue-LLR remains unclear, these data will help to interpret intraoperative tongue recordings. •Intraoperatively, various stimulation sites elicit tongue-long latency responses.•Median nerve and cuneate fascicle stimulations evoke tongue-long latency responses.•The “somatosensory evoked tongue reflex” is a newly described tongue long latency response.•Transcranial electrical stimulation elicits tongue-long latency responses.•Direct trigeminal nerve stimulation elicits the trigemino-hypoglossal reflex.