Seizures, CSF neurofilament light and tau in patients with subarachnoid haemorrhage

Objectives Patients with severe subarachnoid haemorrhage ( SAH ) often suffer from complications with delayed cerebral ischaemia ( DCI ) due to vasospasm that is difficult to identify by clinical examination. The purpose of this study was to monitor seizures and to measure cerebrospinal fluid ( CSF ) concentrations of neurofilament light ( NFL ) and tau, and to see whether they could be used for predicting preclinical DCI . Methods We prospectively studied 19 patients with aneurysmal SAH who underwent treatment with endovascular coiling. The patients were monitored with continuous EEG ( cEEG ) and received external ventricular drainage ( EVD ). CSF samples of neurofilament light ( NLF ) and total tau (T‐tau) protein were collected at day 4 and day 10. Cox regression analysis was applied to evaluate whether seizures and protein biomarkers were associated with DCI and poor outcome. Results Seven patients developed DCI (37%), and 4 patients (21%) died within the first 2 months. Six patients (32%) had clinical seizures, and electrographic seizures were noted in one additional patient (4.5%). Increased tau ratio (proportion tau10/tau4) was significantly associated with DCI and hazard ratio [ HR =1.33, 95% confidence interval ( CI ) 1.055‐1.680. P  = .016]. Conclusion Acute symptomatic seizures are common in SAH , but their presence is not predictive of DCI . High values of the tau ratio in the CSF may be associated with development of DCI .