Autonomic function in chronic fatigue syndrome with and without painful temporomandibular disorder

Abstract

Background: Chronic fatigue syndrome (CFS) is heterogeneous in nature, yet no clear subclassifications currently exist. There is evidence of dysautonomia in almost 90% of patients and CFS is often co-morbid with conditions associated with autonomic nervous system (ANS) dysfunction, such as temporomandibular disorders (TMD). The present study examined the point prevalence of TMD in a sample of people with CFS and explored whether co-morbidity between the conditions is associated with greater ANS dysfunction than CFS alone. Method: Fifty-one patients and 10 controls underwent screening for TMD. They completed a self-report measure of ANS function (COMPASS-31) and objective assessment of heart rate variability during rest and standing (derived using spectral analysis). Frequency densities in the high-frequency (HF) and low-frequency (LF) band were calculated. Results: Patients with CFS were divided into those who screened positive for TMD (n = 16, 31%; CFS + TMD) and those who did not (n = 35, 69%; CFS − TMD). Both CFS groups had significantly higher self-rated ANS dysfunction than controls. CFS + TMD scored higher than CFS − TMD on the orthostatic and vasomotor subscales. The CFS + TMD group had significantly higher HF and significantly lower LF at rest than the other two groups. In discriminant function analysis, self-report orthostatic intolerance and HF units correctly classified 75% of participants. Conclusions: Almost one-third of CFS patients screened positive for TMD and this was associated with greater evidence of parasympathetic dysfunction. The presence of TMD shows potential as an effective screen for patients with CFS showing an autonomic profile and could help identify subgroups to target for treatment.