  An over-reliance on the less-affected limb for functional tasks at the
expense of the paretic limb and in spite of recovered capacity is an
often-observed phenomenon in survivors of hemispheric stroke. The difference
between capacity for use and actual spontaneous use is referred to as arm
nonuse. Obtaining an ecologically valid evaluation of arm nonuse is challenging
because it requires the observation of spontaneous arm choice for different
tasks, which can easily be influenced by instructions, presumed expectations,
and awareness that one is being tested. To better quantify arm nonuse, we
developed the Bimanual Arm Reaching Test with a Robot (BARTR) for
quantitatively assessing arm nonuse in chronic stroke survivors. The BARTR is
an instrument that utilizes a robot arm as a means of remote and unbiased data
collection of nuanced spatial data for clinical evaluations of arm nonuse. This
approach shows promise for determining the efficacy of interventions designed
to reduce paretic arm nonuse and enhance functional recovery after stroke. We
show that the BARTR satisfies the criteria of an appropriate metric for
neurorehabilitative contexts: it is valid, reliable, and simple to use.
