After a stroke, many people “cannot and do not” use their paretic upper limb. With recovery, some people “can but do not” use their paretic upper limb and this non-use should be counteracted with specific rehabilitation.

The aim of the study was to quantify one aspect of the non-use: proximal arm non-use when reaching within one’s arm length in 45 post-stroke and 45 age matched controls. Arm use refers to the contribution of the shoulder and elbow motion to the hand movement towards the target. Proximal arm non-use is calculated as the ratio of the difference between spontaneous arm use and maximal arm use.

We found that proximal arm non-use has very good test-retest reliability, does not depend on time since stroke, increases with impairment (Fugl-Meyer) and loss of function (Box & Block), and most importantly, that 61% of patients with lower impairment (Fugl-Meyer >28/42) exhibit proximal arm non-use.

We conclude that quantifying proximal arm non-use in post-stroke individuals provides novel information that complements routine clinical measures. It is likely that proximal arm non-use quantifies one aspect of the motor reserve that therapists can target in patient specific rehabilitation programs.