State-of-the-Art: Cognitive decline is a major health concern and is closely related to postural and locomotion deficits in older adults. Gait initiation combines motor and cognitive components of movement preparation, and is therefore particularly affected by age-associated deficits in motor control. We have recently shown that this task is also affected by attention. Dual-task interference during gait initiation (i.e. the deficit due to interaction of attention and motor control) can have deleterious consequences, such as falls. At present, only a few drugs (cholinesterase inhibitors and an anti-glutamatergic compound) have shown a small benefit with respect to general cognitive deficits, and there is an urgent need for more specific drugs that have, eg, an effect on dual-task interference. Methylphenidate is a promising candidate for this effect: it is well-known for its positive effect on attention and we have recently shown that it improves axial symptoms in PD patients.

Approach: The aim of this 6-week proof-of-concept, placebo-controlled case-control study is to evaluate the effect of methylphenidate in community-dwelling older adults on dual-task interference during gait initiation. In more detail, we will test the effect of methylphenidate alone (low regimen of 0.3 mg/kg), cognitive training alone, both treatments and placebo, to reduce dual-task interference during gait initiation. Participants will initiate gait while performing a modified version of the Attention Network Test. This test evaluates alertness, orientation and conflict resolution on gait initiation by varying cues of the imperative stimulus that will trigger the step. The primary endpoint - modification of the reaction time to prepare and execute a step – will be measured with force-plates and video-based motion analysis.