Traumatic brain injury (TBI) may afflict areas contributing to both cardiovascular-autonomic modulation and cognitive function. There may be links between cognitive and cardiovascular-autonomic dysfunction (Thayer et al., Ann Behav Med. 2009;37:141–53). To evaluate possible associations between both dysfunctions in patients with a history of TBI (post-TBI-patients), we determined correlations between cardiovascular-autonomic dysfunction and cognitive impairment in post-TBI-patients.Methods
In 86 mild to severe post-TBI-patients (33.13±10.84 years old, 22 women, 36.8±28.9 months after injury), we monitored RR-intervals (RRI), systolic, diastolic blood pressures (BPsys, BPdia), and respiration (RESP) at rest. We calculated parameters of total cardiac-autonomic modulation [RRI-standard-deviation (RRI-SD), RRI-coefficient-of-variation (RRI-CV), RRI-total-powers], sympathetic [RRI-low-frequency-powers (RRI-LF), BPsys-LF-powers] and parasympathetic cardiac modulation [Root-Mean-Square-of-Successive-RRI-Differences (RMSSD), RRI-high-frequency-powers (RRI-HF)], sympathetic-parasympathetic balance (RRI-LF/HF-ratios), and baroreflex-sensitivity (BRS). We assessed executive function using the standardised Trail-Making-Test (TMT) A assessing visuospatial abilities and TMT B assessing executive function, with higher TMT-values indicating poorer function, and calculated correlations between autonomic and cognitive parameters (Spearman-rank-correlation-test; significance: p<0.05).Results
TMT-A inversely correlated with RRI-HF-powers and BRS, TMT-B positively correlated with RRI-LFnu-powers, RRI-LF/HF-ratios, BPsys-LF-powers, but negatively with RRI-HFnu-powers.Conclusions
In post-TBI-patients, more severe cognitive dysfunction is associated with decreasing parasympathetic modulation and baroreflex sensitivity, and increasing sympathetic predominance, changes that increase long-term cardiovascular risk.