The Abnormal Involuntary Movement Scale (AIMS) is a standardized, quantifiable assessment tool designed to detect and track tardive dyskinesia (TD). TD is a neurological disorder characterized by abnormal, involuntary movements of the face, mouth, trunk, or limbs, often developing after long-term treatment with neuroleptic (antipsychotic) medications. The AIMS test provides a consistent method for clinical professionals to monitor the severity of these movements over time. By systematically assessing different body regions, the scale serves as a valuable instrument for monitoring the effects of long-term medication use and guiding treatment decisions.
Preparing for the Assessment
Before beginning the formal procedure, the clinician should ensure the patient is in an optimal environment for accurate observation. The examination should ideally take place in a quiet, private room with a hard, firm chair that does not have armrests. The patient should be asked to remove any items from their mouth, such as gum or candy, and, for a thorough examination of the feet, shoes and socks should also be removed.
Before starting the movement tasks, the clinician must establish baseline information. This involves asking the patient about the current condition of their teeth, whether they wear dentures, and if they are experiencing any dental discomfort.
The patient is also asked if they have noticed any unusual movements in their mouth, face, hands, or feet, and to what extent these movements interfere with their daily life. Unobtrusive observation of the patient, perhaps while they are seated in the waiting room or as they enter the examination space, can provide initial data on their movements at rest.
Standardized Test Administration Procedure
The AIMS procedure involves a series of specific instructions designed to activate or reveal involuntary movements across different body areas. The clinician first observes the patient sitting with their hands resting on their knees, legs slightly apart, and feet flat on the floor, looking for movements across the entire body. The patient is next asked to let their hands hang unsupported, either between their legs or over their knees, which allows for closer observation of the hands and fingers.
The clinician then focuses on the facial and oral region. The patient is asked to open their mouth so the tongue can be observed at rest, a step typically performed twice. Following this, the patient is instructed to protrude their tongue, and the clinician observes for any abnormalities in its movement, also performed twice. To activate movements in the extremities, the patient taps their thumb rapidly against each finger for ten to fifteen seconds, first with one hand and then the other, while the clinician watches the face and legs for any induced movements.
For further assessment of the limbs and trunk, the patient is asked to stand up, allowing the clinician to observe their body in profile, including the hips. The patient is then asked to extend both arms straight out in front of them with the palms facing downward, which is an activation technique used to reveal movements in the trunk, legs, and mouth. The procedure concludes with the patient walking a few paces, turning, and walking back to the chair, which is done twice to observe the gait and hands. The examiner may also gently flex and extend the patient’s arms one at a time to check for rigidity.
Quantifying Observations and Scoring
The AIMS test uses a five-point severity scale (0 to 4) to quantify observed movements, where 0 indicates no abnormal movements and 4 indicates severe movements. The clinician rates the first seven items, which correspond to movements in the facial, oral, extremity, and truncal regions, by recording the highest severity observed for each body area. When assigning a score, the clinician considers the amplitude (size) and the frequency (rate) of the involuntary movements.
Items 1 through 7 are the primary movement ratings used to calculate the total score. The remaining items cover global judgments, such as the overall severity of the abnormal movements, resulting incapacitation, and the patient’s awareness of the movements. The final two items are dedicated to documenting the patient’s dental status, including current issues with teeth or dentures. Accurate documentation includes noting any instances where a specific body part could not be assessed due to patient limitations or external factors.
Interpreting Results and Clinical Application
The quantified AIMS result provides clinicians with the necessary data to make informed decisions regarding the patient’s care. A positive AIMS examination is generally recognized as a score of 2 in two or more of the movement areas, or a score of 3 or 4 in a single movement area. These threshold scores often indicate the presence of tardive dyskinesia and warrant a clinical discussion about potential intervention.
The resulting score guides treatment adjustments, such as reducing the dosage of the current antipsychotic medication or switching therapeutic agents. Given the risk of TD with long-term neuroleptic use, the AIMS test is recommended for regular screening, often performed at baseline and then quarterly or biannually, especially for patients on high-risk medications. The scale is an established tool for monitoring the progression or improvement of dyskinesia over time, making it an indispensable part of routine clinical evaluations.