Gait is specifically impaired in Parkinson's disease (PD). External auditory cue based on a binary rhythm tested in PD patients disappear when the stimulus is removed. Golden Ratio (GR)is intrinsic in the human gait, but in PD patients this GR has been found impaired. Aim of the study is the administration of an auditory external cue based on a personalized Golden Ratio-rhythm which could potentially assist people with PD to cope with the difficulties that they experience while walking, thus increasing their mobility and autonomy.

Gait is specifically impaired in Parkinson's disease (PD). External auditory cue based on a binary rhythm has been successfully used in people with PD to improve their gait quality, but the beneficial effects disappear when the stimulus is removed. Recent evidences have shown that, in healthy subjects, the structure of walking relies on a number, called Golden Ratio (GR), based on a perfect proportion between different gait phases. While GR is known to be impaired in people with PD, there are few evidences that a GR-based auditory stimulus could support people with PD in counteracting gait alterations. As hypothesis, an auditory external cue based on a personalized GR-rhythm could assist people with PD to cope with the difficulties that they experience while walking, thus increasing their mobility and autonomy, and that the nature of this GR-rhythm allows to maintain the beneficial effects in time. Two personalized auditory rhythms (a binary rhythm and a GR-rhythm) will be alternatively administered to each participant (see diagram below). Patient-specific rhythms will administered by a user-friendly ad-hoc app for smartphone. Two assessments will be performed during these 24 weeks, to assess treatment efficacy. At the end of the 24th week, half of patients will continue with the GR-rhythm and, in a final assessment, we will see if the effect lasts over time.

Inclusion Criteria:

• diagnosis of idiopathic PD, as proposed by the Brain Bank Criteria for PD, since at least 5 years
• suffered from a rigid akinetic form of bilateral Parkinson's Disease (Hoehn and Yahr: 2-3), according to current criteria
• to be on stable treatment regimen for at least the 3 months before the recruitment
• Mini Mental State Examination score >24
• Do not vary the pharmacological treatment during the entire duration of the study
• Be tested in "ON" medication state

Exclusion Criteria:

• inability to stand or walk without aids or supports
• factors affecting gait such as hip replacement, musculoskeletal disorders, uncorrected vision or vestibular problems;
• inability to follow instructions;
• severe dysautonomia with marked hypotension, major depression, dementia, pregnancy, or cardiac pacemaker