Chronic Headache: The Interplay of Muscle Tension, its Discrimination, and Body Awareness.

Background: Chronic pain patients often exhibit altered processing of internal bodily sensations, especially in the musculoskeletal domain, and impaired body awareness. This case-control study investigated the association between resting electromyographic (EMG) activity, musculoskeletal tension discrimination and body awareness in chronic headache (CH) patients compared to healthy controls (HC).

Methods: Twenty-one patients diagnosed with chronic headache and 22 matched healthy controls performed a muscle tension discrimination task while EMG was recorded from the frontalis (pain-related) and biceps brachii (pain-unrelated) muscles. Questionnaires assessed body awareness and pain-related cognitive and affective factors.

Results: Compared to HC, CH patients showed higher resting muscle activity (β = 1.32; p < 0.001) and lower discrimination (β = -0.12; p = 0.007) only in the pain site. CH patients exhibited reduced body awareness (η²p = 0.19; p = 0.003), higher anxiety (β = 3.10; p = 0.032), catastrophizing (η²p = 0.30; p < 0.001), and helplessness (η²p = 0.19; p = 0.004). Notably, lower muscle tension discrimination was associated with both higher resting frontalis EMG (ρs = -0.31; p = 0.043) and catastrophizing (ρs = -0.39; p = 0.009).

Conclusions: Patients with CH exhibit a site-specific deficit in muscle tension discrimination, accompanied by elevated resting pericranial muscle tension, reduced body awareness, and maladaptive cognitive coping strategies. The association between catastrophizing and impaired discrimination highlights the interplay between cognitive-affective factors and psychophysiological dysregulation in CH. These findings underscore the importance of multidimensional assessment in patients with CH in order to identify targeted psychophysiological treatment.