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LAMS score: Los Angeles Motor Scale (Llanes 2004)

The LAMS score, or Los Angeles Motor Scale, is a three-item motor score for suspected stroke in the field. Facial droop scores 0 or 1, arm drift 0 to 2 and grip 0 to 2, so the LAMS score runs from 0 to 5. Magent's calculator adds the three item scores you supply and returns the total.

Not a medical device. Not a diagnosis or dosing recommendation.

Use this calculator via API

What is the LAMS score?

Paramedics in Los Angeles already used the Los Angeles Prehospital Stroke Screen (LAPSS), which checks the face, arm and grip for one-sided weakness. Llanes and colleagues gave those three motor checks graded points, turning a yes/no screen into a severity number.

A higher total means more motor weakness on examination. Llanes 2004 didn't define a cut-off, risk class or probability for the total, and the calculator doesn't add one.

The LAMS score formula

LAMS = facial droop  (0 absent, 1 present)
     + arm drift     (0 absent, 1 drifts down, 2 falls rapidly)
     + grip          (0 normal, 1 weak, 2 no grip)

total 0 to 5

Exact expression the calculator uses:

LAMS = facial_droop (0 absent, 1 present) + arm_drift (0 absent, 1 drifts down, 2 falls rapidly) + grip (0 normal, 1 weak, 2 no grip); Llanes 2004 LAPSS motor items; max 5

Inputs

InputLevelsRange
facial_droop0 absent, 1 present0 to 1
arm_drift0 absent, 1 drifts down, 2 falls rapidly0 to 2
grip0 normal, 1 weak, 2 no grip0 to 2

All three are whole numbers you assign from the examination. The calculator doesn't examine anyone.

How the calculation works

  1. Face. Facial droop present scores 1.
  2. Arm. An arm that drifts down scores 1; one that falls rapidly scores 2.
  3. Grip. A weak grip scores 1; no grip scores 2.
  4. Add. The three scores give a total from 0 to 5. The calculator returns the items as well as the total.

Worked examples

These use Magent's own expected values for the calculator.

Example 1: no weakness

  1. Facial droop 0, arm drift 0, grip 0.
  2. Total 0 out of 5.

Example 2: facial droop alone

  1. Facial droop present (1), arm and grip normal.
  2. Total 1.

Example 3: an arm that falls rapidly

  1. Arm drift 2, face and grip normal.
  2. Total 2. An arm that drifts down without falling would give 1.

Example 4: no grip

  1. Grip 2, face and arm normal.
  2. Total 2. A weak grip would give 1.

History of the LAMS score

Llanes JN, Kidwell CS, Starkman S, Leary MC, Eckstein M and Saver JL described the scale in Prehospital Emergency Care in 2004, in "The Los Angeles Motor Scale (LAMS): a new measure to characterize stroke severity in the field". They built it from the motor items of the LAPSS. Thresholds for the total came from later studies, not from this paper.

When it's used

LAMS is scored when a stroke is suspected before hospital, to put a number on motor weakness that can be passed on to the receiving team.

Where it's used

Ambulances and other prehospital settings, and sometimes in emergency departments.

Who uses it

Paramedics and emergency medical technicians, and emergency and stroke teams reading their handover. The calculator adds the three items.

Limits of the calculation

  • It measures motor weakness on three items. It doesn't cover speech, vision, sensation or other stroke signs.
  • The calculator returns a number with no cut-off or class.
  • It doesn't say where a person should be taken or what should be done.
  • Other conditions can cause one-sided weakness.
  • This page doesn't say what a result means for a particular person.

Clinical decisions belong to a qualified clinician who knows the patient.

  • NIHSS is a much longer stroke examination covering many domains, usually done in hospital.
  • FAST-ED and RACE are other prehospital stroke scales with more items, including speech or gaze.
  • ABCD2 scores short-term stroke risk after a transient ischaemic attack.

Glossary

  • LAPSS: Los Angeles Prehospital Stroke Screen, the screen LAMS was built from.
  • Arm drift: an outstretched arm sinking when the person holds it up.
  • Prehospital: before arrival at hospital.
  • Motor weakness: reduced strength or control in the face or limbs.

Common mistakes

  • Giving facial droop 2 points. Face tops out at 1.
  • Going past the ranges. Arm drift and grip top out at 2.
  • Adding a cut-off. Llanes 2004 didn't publish one, and the calculator doesn't apply one.
  • Treating LAMS as a full stroke examination. It covers three motor items.

Source

Llanes JN, et al. The Los Angeles Motor Scale (LAMS): a new measure to characterize stroke severity in the field. Prehosp Emerg Care. 2004;8(1):46-50. DOI: 10.1080/312703002806. PMID: 14691787

Frequently asked questions

What is the highest LAMS score?

5: facial droop 1, arm drift 2 and grip 2.

What does LAMS stand for?

Los Angeles Motor Scale.

Does the calculator flag a large vessel occlusion?

No. Llanes 2004 didn't define a cut-off for that, and the calculator returns the total without one.

How long does LAMS take?

It uses three quick motor checks that are already part of the LAPSS, so it adds little time to a field assessment.

Is LAMS the same as LAPSS?

No. LAPSS is a yes/no screen. LAMS gives graded points to its three motor items.