Prevalence of cognitive complaints and impairment in patients with Chronic Subdural Hematoma and recovery after treatment

Chronic subdural hematoma (CSDH) is a frequently occurring neurological disease associated with older age and use of anticoagulants. Symptoms vary from headaches to coma, but cognitive deficits can also be present. However, exact prevalence and severity of cognitive deficits in CSDH are still unknown. In this systematic review, we aim to assess cognitive status of patients with CSDH, at presentation and after treatment. PubMed, Embase and PsycInfo were searched for articles concerning cognition in CSDH. We divided cognitive changes into subjective cognitive deficit (cognitive complaints [CC]) and objective cognitive deficit (cognitive impairment [CI]). Two reviewers independently selected studies for inclusion and subsequently extracted data. Quality assessment was done by means of the Newcastle-Ottawa Scale. Reported prevalence of CC and CI was pooled with random effects meta-analysis. Out of 799 identified references, 22 met inclusion criteria. Twenty-one articles reported on prevalence of CC/CI and one study reported solely on CSDH patients with cognitive deficit. Estimated pooled prevalence of both CC and CI in CSDH at presentation was 45% (95% confidence interval [CI]: 36-54%). Four studies concerned a prospective evaluation of the effect of surgical treatment on cognition. These proved to be of fair to good quality after quality assessment. The estimated pre-treatment prevalence of objectified cognitive impairment was 61% (95% CI: 51-70%) decreasing to 18% (95% CI: 8-32%) post-surgery. From this review it can be concluded that CC and CI are very common in CSDH, with a tendency to improve after treatment. Therefore, we underline the importance of increased attention to cognitive status of these patients, with proper testing methods and treatment-testing intervals.