Background Altered consciousness is an important symptom of acute stroke but assessment may be challenging when cognitive or language deficits are present. Callers are routinely questioned about conscious level by emergency medical services (EMS) call handlers for any presenting problem.

Objective This study aimed to identify and compare how patients' conscious level was questioned, described and interpreted by callers and call handlers during acute stroke calls.

Method Audio recordings of 643 EMS calls for patients with suspected or confirmed acute stroke, admitted to one hospital in North West England over a 12-month period were retrieved from EMS recordings. Calls from primary care physicians were excluded. The caller's response to two standard questions was coded: ‘Is the patient conscious?’ and ‘Is he/she completely awake?’, and other relevant dialogue. Responses which suggested misinterpretation of terms relating to conscious level, or where the call handler used additional clarifying questions, were analysed in detail.

Results 109/643 (17%) of the calls had an altered level of consciousness recorded on the ambulance report form. Calls often contained unscripted, protracted dialogue about conscious level. Conscious level was difficult for the caller to determine, miscommunicated, or conflated with breathing difficulties.

Conclusion Ambiguities and contradictions in dialogue about conscious level arise during ambulance calls for suspected and confirmed stroke. Further study is needed to identify whether these issues also arise in non-stroke calls, and which terms are best understood by the public in describing conscious level.