Is it possible to use the Structural Dimension Analysis of Motor Memory (SDA-M) to investigate representations of motor actions in stroke patients?

OBJECTIVE

To determine the feasibility of the Structural Dimension Analysis of Motor Memory (SDA-M), a method derived from sports psychology, in establishing the mental representations of complex movements in patients after stroke.

DESIGN

Case series of patients, with age-matched healthy controls.

SETTING

A rehabilitation nursing home.

SUBJECTS

Sixteen patients 3-26 weeks after their stroke, and 16 controls.

INTERVENTION

Each control had the SDA-M performed within a 10-day period. Each stroke patient had the SDA-M performed once. In the SDA-M the subject was asked to state for each of 10 actions involved in drinking from a cup whether it is functionally close to each of the other nine or not.

MAIN MEASURES

The raw data from the SDA-M were transformed through cluster analysis into Euclidean distances and tree diagrams to illustrate the internal representation of the action.

RESULTS

All subjects were able to perform the assessment. Healthy controls all had a similar set of Euclidean distances and tree diagrams that were 'normal'. The tree diagrams remained very similar on the three occasions. Four stroke patients had tree diagrams that were 'normal'. The remaining twelve had tree diagrams that differed greatly both from the 'normal' and from each other, with much less clustering of actions. Patients with more severe stroke appeared to have more disordered tree diagrams.

CONCLUSION

The Structural Dimension Analysis of Motor Memory (SDA-M) is a feasible method for investigating the mental representation of internal motor action plans in stroke patients, giving similar data in stable healthy people and revealing abnormal patterns in patients after stroke.