Patients with Parkinson's disease show a gait disturbance which is considered as one of the most disabling aspect of the disease that strongly impacts on patients' autonomy and quality of life. The mechanism underlying gait impairment is multi-factorial, reflects the global motor impairment of patients with PD and is mainly related to a neurotransmitter deficiency inducing bradykinesia, rigidity, abnormal trunk control and postural instability. For this reason, and considering the impact of social and economic costs, one of the main foci of intervention in patients with PD should be treating gait abnormalities. This need is further reinforced by the knowledge that gait outcomes are correlated with longevity, cognitive decline and adverse events.

Besides the shorten-step gait clinical description of the gait disorder in PD, in the last years, studies using modern 3D motion analysis systems have further detailed the gait pattern in PD disclosing abnormalities in cadence, stance duration, swing duration, double support duration, leg length, step length, velocity, hip, knee and ankle ROMs. Such abnormal gait parameters seem to correlate with the clinical outcomes of UPDRS score, H-Y stage and milliequivalents of levodopa taken. Importantly, gait parameters can either normalize or improve after several rehabilitative treatment strategies including physiotherapy, assistive equipment, sensory cueing, treadmill training, physical activity, home base exercises. However, none of the previous studies specifically investigated which biomechanical factor can be modified after rehabilitation and which clinical characteristic can predict the rehabilitation-induced gait improvement. This would be extremely important to typifying, grouping and selecting patients, optimizing the rehabilitative strategies and cost management.

The aims of the present study were to evaluate in a sample of patients with PD: i) which gait parameters can be modified after a short-term rehabilitation program; ii) which, if any, clinical variable can predict the improvement of the gait function after rehabilitation. At this aim we quantitatively evaluated the gait performance of PD patients by means of a 3-D motion analysis system.

Fifty out of 67 patients with idiopathic PD assessed for eligibility were recruited at Rehabilitation Unit of Department of Medical and Surgical Sciences and Biotechnologies, University of Rome, Sapienza, and at Rehabilitation Unit of Policlinico Italia Centre, Rome, Italy. Patients were admitted for outpatient rehabilitation between May 2014 and April 2017. The inclusion criteria were a diagnosis of idiopathic PD according to UK bank criteria and Hoehn and Yahr stages 1 to 3. All patients were in a stable drug program and had adapted to their current medications for at least 2 weeks. Exclusion criteria were: cognitive deficits (defined as scores of <26 on the Mini-Mental State Examination [MMSE]), moderate or severe depression (defined as scores of >17 on the Beck Depression Inventory [BDI]), and orthopedic and other gait-influencing diseases such as arthrosis or total hip joint replacement.

All participants could walk independently without walking devices. All patients were taking oral administrations of levodopa (18 patients), dopamine agonists (5 patients), or both (13 patients) and were recorded in on phase.

Severity of parkinsonism was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS-II and III) and the Hoehn and Yahr staging system.

The study complied with the Helsinki Declaration and received local ethics committee approval. Prior to taking part in the study, all the participants gave a written consent after a fully explanation of the experimental procedure.

Inclusion Criteria:

• Diagnosis of idiopathic PD according to UK bank criteria
• Hoehn and Yahr stages 1 to 3.
• All patients were in a stable drug program and had adapted to their current medications for at least 2 weeks

Exclusion Criteria:

• Cognitive deficits (defined as scores of <26 on the Mini-Mental State Examination [MMSE]),
• moderate or severe depression (defined as scores of >17 on the Beck Depression Inventory [BDI]), -. orthopedic and other gait-influencing diseases such as arthrosis or total hip joint replacement.

Fifty out of 67 patients with idiopathic PD assessed for eligibility were recruited at Rehabilitation Unit of Department of Medical and Surgical Sciences and Biotechnologies, University of Rome, Sapienza, and at Rehabilitation Unit of Policlinico Italia Centre, Rome, Italy. Patients were admitted for outpatient rehabilitation between May 2014 and April 2017. All patients were in a stable drug program and had adapted to their current medications for at least 2 weeks.

All participants could walk independently without walking devices. All patients were taking oral administrations of levodopa (18 patients), dopamine agonists (5 patients), or both (13 patients) and were recorded in on phase. Patients' clinical and anthropometric characteristics.

Severity of parkinsonism was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS-II and III) and the Hoehn and Yahr staging system.