Age and sex impact resting-state EEG aperiodic activity beyond symptom associations in persistent post-concussive symptoms

Objective

to investigate whether resting-state EEG aperiodic parameters (i.e., offset and exponent) are associated with symptom burden and demographic factors in patients with persistent post-concussive symptoms (PPCS) and differ from healthy controls.

Methods

In this cross-sectional observational study, resting-state eye-closed high-density EEG was recorded in patients with PPCS and in age-matched healthy controls. Aperiodic parameters were extracted from EEG power spectra. In patients, hierarchical multiple linear regression models included age and sex as a base model, with additional demographic and clinical symptoms entered separately. Patient-control differences were assessed using multiple linear regression adjusted for age and sex.

Results

Seventy patients with PPCS (54 female; 39.57±12.21 y.; 109.5 [76.5; 196] days post-concussion) recruited from a concussion care pathway and 38 healthy controls (17 female; 39.61±13.57 y.) were included. In patients, younger age and male sex were associated with higher offset and exponent values (all p ≤.014). None of the additional demographic and clinical variables improved model fit beyond age and sex (all p ≥.143). After adjustment for age and sex, neither offset ( p =.898) nor exponent ( p =.100) differed between patients and controls.

Conclusion

Resting-state aperiodic EEG parameters were consistently associated with age and sex, but not with self-reported symptom burden or clinical characteristics in patients with PPCS. Not accounting for these factors may generate apparent group differences attributable, at least in part, to demographic variability.

Significance

Age and sex are important sources of inter-individual variability in resting-state aperiodic EEG activity and should be systematically considered when investigating such features.

Highlights

• Age and sex significantly impact resting-state EEG aperiodic activity.

• Aperiodic EEG parameters were not associated with symptom burden in persistent post-concussive symptoms.

• Aperiodic offset and exponent did not differ between patients with persistent post-concussive symptoms and healthy controls after adjustment for age and sex.