AIMS Test · Abnormal Involuntary Movement Scale Scoring for Tardive Dyskinesia

The AIMS (Abnormal Involuntary Movement Scale) is a 12-item rating scale for dyskinetic movements, completed by a clinician after a short structured examination. It was developed by the Psychopharmacology Research Branch of the US National Institute of Mental Health and published in the 1976 ECDEU Assessment Manual for Psychopharmacology ¹.

What does the AIMS measure?

The AIMS records the occurrence and severity of involuntary movements during the examination ¹. It was published for people receiving neuroleptic (antipsychotic) drugs ¹, and it has become the widely accepted, easy-to-use measure for assessing the severity and extent of tardive dyskinesia, used both for routine monitoring and to standardize clinical trials ⁴.

The 12 items fall into four groups ¹:

• Facial and oral movements (items 1-4). Muscles of facial expression, lips and the area around the mouth, jaw, and tongue.
• Limb movements (items 5-6). Upper limbs (arms, wrists, hands, fingers) and lower limbs (legs, knees, ankles, toes). Tremor is not rated.
• Trunk movements (item 7). Neck, shoulders and hips.
• Global judgements (items 8-10). Overall severity, incapacitation, and the person's own awareness of and distress about the movements, rated from their report only.
• Dental status (items 11-12). Current problems with teeth or dentures, and whether dentures are usually worn.

The AIMS sits in the same 1976 manual as the BPRS and the CGI ¹.

Terms of use

The AIMS was published by the National Institute of Mental Health in the ECDEU Assessment Manual for Psychopharmacology, a US Department of Health, Education, and Welfare publication (DHEW Publication No. (ADM) 76-338). The manual states that the scale was made available "to the larger scientific community through the ECDEU Battery", and it carries no copyright notice for the AIMS ¹. This page describes the items by area and does not reproduce the form; the manual is available from the Internet Archive ¹.

How do you give the AIMS?

• Who gives it. A clinician trained in the examination. Rater experience affects agreement ⁵, and published guidance supports its use by a multidisciplinary team within an ongoing treatment program ².
• Observe at rest first. Before or after the structured examination, watch the person unobtrusively at rest, for example in a waiting room ¹.
• Setting. A hard, firm chair without arms ¹.
• The examination. The manual sets out 12 steps ¹. In summary:
  1. Ask the person to remove anything in their mouth, and ask about their teeth, dentures and any movements they notice and how much these bother them.
  2. Observe the whole body while the person sits with hands on knees and feet flat, then with hands hanging unsupported.
  3. Observe the tongue at rest in the open mouth, then protruded, twice each.
  4. Ask the person to tap the thumb against each finger quickly for 10 to 15 seconds with each hand, while observing the face and legs.
  5. Flex and extend each arm to check for rigidity (rated on a separate scale, not the AIMS).
  6. Observe the person standing in profile, with arms outstretched, and walking a few paces, turning and walking back, twice.
• Time window. Rate only what is seen during the examination period ¹.
• When. The manual called for one rating before treatment and at least one after ¹. Later guidance recommends regular screening throughout antipsychotic treatment and including the examination in the informed consent process ^{2 4}.

How do you score and interpret the AIMS?

Movement items (1-7). Rate the highest severity observed in each area ¹:

Movements that appear only on activation (during tasks such as finger tapping) are rated one point lower than the same movements seen spontaneously ¹.

Global items (8-10). Overall severity and incapacitation are rated from none (0) to severe (4). Awareness is rated from no awareness (0) to aware with severe distress (4), from the person's own report ¹.

Dental items (11-12). Recorded as no (0) or yes (1) ¹.

No total-score cut-off. The 1976 manual sets no total score or severity bands, which is why this page has no score interpreter ¹. Clinical trials report a total AIMS severity score and track change in it ⁴, but there is no universal cut-off.

Research criteria for tardive dyskinesia. The criteria most often used to standardize diagnosis in research, developed by Schooler and Kane, look at the pattern of movement ratings across body areas ^{3 4}:

A lower threshold suggested by Glazer and colleagues (a total of 3 with at least one area rated mild) did not gain wide use in research ⁴. In clinical practice, even mild movements in one area, such as lip smacking that the person notices and finds embarrassing, may be significant and enough for a diagnosis ⁴. The AIMS is not specific for tardive dyskinesia, so abnormal movements call for a clinical assessment of their cause ².

Psychometric properties

• No formal validation at release. The 1976 manual states that preliminary versions were used to rate video recordings with relatively good consensus, but no formal inter-rater reliability studies had been done, and the scale was released "despite the fact that it has not been validated using psychometric procedures" because of the need for an assessment in the field ¹.
• Rater experience. In 33 people with tardive dyskinesia rated independently by two experienced and two inexperienced raters over 10 months, experienced raters agreed more closely and were more consistent over time ⁵.
• Scoring conventions. Munetz and Benjamin expanded the original instructions and proposed conventions to make scoring more consistent ².
• Use in research. The AIMS is widely accepted for rating tardive dyskinesia, and the Schooler-Kane criteria based on it have standardized diagnosis across clinical and epidemiological studies ⁴.

Limitations

• Not a diagnosis. The AIMS records movements, not their cause; it is not specific for tardive dyskinesia ².
• No universal cut-off. The manual defines no total-score bands ¹, and different research thresholds classify the same ratings differently ⁴.
• Rater dependence. Agreement depends on rater experience, and the scale does not capture the quality, frequency and amplitude of movements separately ⁵. It also does not record the type of movement, such as dystonic versus stereotyped ⁴.
• Time. The full examination can be hard to fit into a busy clinic, and abridged screening approaches have been suggested for routine visits ⁴.
• Snapshot. It rates only the examination period ¹.