Los Angeles Motor Scale (LAMS): Explanation and Clinical Context The Los Angeles Motor Scale (LAMS) is a rapid prehospital stroke assessment tool designed to predict the likelihood of a large vessel occlusion (LVO) in patients presenting with acute neurological deficits.
It evaluates three motor domains: facial droop, arm drift, and grip strength. Each domain is scored individually (Facial: 0–1; Arm: 0–2; Grip: 0–1), yielding a total score ranging from 0 to 5. Higher scores indicate more severe motor deficits and higher probability of LVO.
Clinically, LAMS is used by EMS to triage patients, determining whether they should be transported directly to a comprehensive stroke center capable of performing mechanical thrombectomy. LAMS has been validated to reliably predict anterior circulation LVO in the prehospital setting and helps reduce treatment delays.
Reference:
Gonzalez RG, et al. Los Angeles Motor Scale to identify large vessel occlusion strokes in the field. Stroke. 2008;39:2464-2468.
Hastrup S, et al. Prehospital prediction of large vessel occlusion stroke: a systematic review. Stroke. 2016;47:499-505.