Practising walking and thinking together or separately

Intervention: One hundred twenty subjects (sixty at each side) will receive a six week long therapy intervention program consisting of integrated dual task training,four times a week, for thirty minutes long. Twice a week this therapy will be guided by an especially trained therapist and the other two times, the patients have to practise by themselves. The consecutive dual task training group will receive the same amount of therapy however consisting of traditional gait training and separate training of cognitive tasks. Primary outcome: Primary outcome measure is Dual Task (DT) gait performance. DT gait performance will be evaluated by measuring gait speed at maximum levels while performing untrained cognitive tasks. At baseline, the appropriate cognitive task (sufficient level of cognitive challenge for each patient) will be determined Secondary outcome: • Cognitive performance during dual task walking; amount of errors are scored during the dual task assessment on the walkway. • Gait performance during the trained cognitive tasks; as measured by the GAITRite system. • Dual task interference outcomes; by comparing the gait performance on the single task and dual task assessment. • Single task gait performance: speed, stride length and cadence; as measured by the GAITRite system. • Single task cognitive performance (during sitting); amount of errors is scored during a single cognitive task which is similar to the cognitive task that is used in the dual task test session.