The effect of tongue-to-palate on deep neck flexor activity.

Deep neck flexor (DNF) muscles contribute to cervical stability and proprioception. Reduced muscle strength and endurance lead to faulty movement patterns, muscle imbalances, and dysfunction. Potentially, the orofacial muscles contribute to cervical strength by providing stability through muscular connections. This study examined effects of tongue muscle activity on cervical spine muscular stiffness. Twenty-three healthy subjects assumed three supine positions [at rest (AR), chin tuck (CT), and head lift (HL)] with and without tongue-to-palate pressure. The DNF stiffness was measured using shear wave elastography. Without tongue-to-palate, stiffness increased with CT and HL compared to AR (p <0.001) but not between CT and HL (p = 0.22). Tongue-to-palate increased stiffness AR (p <0.001) but not during CT (p = 0.95) or HL (p = 0.67). Stiffness levels between the AR and HL conditions during tongue-to-palate performance did not differ (p = 0.734), but CT stiffness was significantly greater than AR (p = 0.029) with tongue-to-palate. Tongue-to-palate AR increases DNF stiffness to a similar level as HL with or without tongue-to-palate, while CT with or without tongue-to-palate resulted in the highest stiffness levels. Tongue-to-palate pressure AR or with CT performance may be alternatives to HL strengthening in healthy necks. This may be a useful strategy to increase cervical stability during loads on the cervical spine.