Time Is Brain: Improving Diagnosis Before Hospital Arrival
Nedim Leto will defend his PhD thesis at the University of Bergen on 28 August 2026. The thesis is entitled “Enhancing Prehospital Stroke Identification: Diagnostic Accuracy and System-of-Care Implications.”
Stroke is one of the leading causes of death and long-term disability in Norway. Approximately 85% of strokes are ischemic strokes (caused by a blood clot) and 15% are hemorrhagic strokes (caused by bleeding in the brain). During an acute stroke, brain cells die at a rapid rate. The principle “time is brain” reflects the fact that every minute without treatment results in the loss of millions of brain cells. Rapid diagnosis and treatment are therefore crucial for preserving brain function.
The doctoral thesis is based on three scientific papers and examines how accurately healthcare professionals identify stroke in the prehospital phase, that is, before the patient arrives at the hospital.
In the first paper, Leto and his co-authors found that the ambulance service’s screening test for large vessel occlusion stroke identified only 12% of patients who could potentially benefit from emergency clot removal treatment (thrombectomy).
In the second paper, the authors showed that when the Emergency Medical Communication Centre (EMCC) correctly identified an ischemic stroke, the entire treatment pathway became faster: less time was spent at the scene, thrombolytic treatment was administered more quickly, and patients were almost twice as likely to receive such acute treatment.
The third paper revealed that the EMCC also generated a substantial number of false alarms: only about one in seven ambulance dispatches for suspected stroke turned out to be an actual stroke. The remaining cases were stroke mimics, such as postictal paralysis following epilepsy or migraine-related neurological symptoms.
The consequences are twofold. Too few correct stroke alerts mean lost treatment time for stroke patients, while too many false alarms contribute to overcrowded emergency departments, potentially affecting the care of other critically ill patients.
The findings highlight the need for more accurate diagnostic tools and assessment methods in both ambulance services and Emergency Medical Communication Centres. Improved diagnostic accuracy could help ensure that more stroke patients receive timely acute treatment while healthcare resources are used more efficiently.
About the Candidate
Nedim Leto (born 1999) graduated with a medical degree (cand.med.) from the University of Bergen in 2025 and currently works as a medical intern (LIS1 physician) at Stavanger University Hospital (SUS). He completed the Medical Student Research Programme at the Faculty of Medicine, University of Bergen. The doctoral work was carried out at the Department of Clinical Medicine 1, University of Bergen, and the Regional Emergency Medical Services Competence Centre of Western Norway (RAKOS), Stavanger University Hospital. The principal supervisor was Associate Professor Thomas Werner Lindner, with Professor Elisabeth Farbu serving as co-supervisor.