Dual task interference on postural sway, postural transitions and gait in people with Parkinson's disease and freezing of gait.

The study used 30 people without freezing and 24 people with freezing, so the sample was not large. All Parkinson's testing was done after at least 12 hours without medication, so results may not apply to people taking medication. The paper reports 56 PD subjects recruited but then analyses 30 without freezing and 24 with freezing, and does not explain the difference. The 15 healthy older adults were used as a reference and were not statistically compared with the Parkinson's groups. Participants were not told which task to prioritize, and the counting task may not have been active during step initiation or turning. The examiner used the word 'Walk' to cue stepping, which may have changed the first-step response. Turning was tested only as a 180-degree turn, not a 360-degree turn.

OHSU and Dr. Horak have a significant financial interest in ADPM and are employees of ADPM, a company with a commercial interest in the results and technology. The disclosure says this was reviewed and managed by OHSU and the VA Portland Health Care System.

Do not read this as evidence that training with a second task improves walking. The study did not give a training programme or test change over time. It only compared how much movement changed when a counting task was added. Do not assume standing sway or turning will show the same extra cost.