Each patient will have 2 visits :

• First visit in the "ON" state phase, i.e. when their oral treatment allows the maximum improvement of dopamine-responsive parkinsonian symptoms.
• A second visit in the "OFF" phase after having stopped taking their antiparkinsonian medications for at least 12 hours before the start of the visit, in order to promote episodes of FOG

For each visit, the patient will be asked to walk at a comfortable speed under the following 3 conditions:

• Normal condition without additional physical and verbal tasks
• Condition with added physical tasks: The physical task of holding a ball in the center of a tray.
• Condition with added verbal tasks: The verbal task of saying as many words as possible starting with a specific letter.

Conditions of passage are randomized per patient. Each subject will complete the course a maximum of 18 times in blocks of 3 conditions (normal, double physical task and double verbal task). A rest period will be observed.

Each patient will have 2 visits :

• First visit in the "ON" state phase, i.e. when their oral treatment allows the maximum improvement of dopamine-responsive parkinsonian symptoms.
• A second visit will be scheduled 15 +/- 7 days from the first. Patients will then be assessed in the "OFF" phase after having stopped taking their antiparkinsonian medications for at least 12 hours before the start of the visit, in order to promote episodes of FOG

For each visit, the patient will be asked to walk at a comfortable speed under the following 3 conditions:

• Normal condition without addition of additional physical and verbal tasks
• Condition with added physical tasks: The physical task of holding a ball in the center of a tray
• Condition with added verbal tasks: The verbal task of saying as many words as possible starting with a specific letter.

Conditions of passage are randomized per patient. Each subject will complete the course a maximum of 18 times in blocks of 3 conditions.

Every second of the course will be analyzed to define :

• the "true positive" time: FOG detected by the algorithm and the two experts
• True negative" time: FOG detected by neither the algorithm nor the two experts
• False positive" time: FOG detected by the algorithm but not by the two experts
• False negative" time: FOG not detected by the algorithm but detected by both experts For each course completed, accuracy will then be calculated as the ratio between the sum of the time spent in "true positive" and "true negative" divided by the time taken to complete the course.

The average of these ratios is then calculated to estimate the accuracy of all runs performed, i.e. taking into account all repetitions performed by patients, regardless of run type and ON/OFF status.

Sensitivity will be calculated as the ratio of time spent in "true positive" divided by the sum of time spent in "true positive" and "false negative". These ratios will then be averaged to estimate accuracy over all the runs performed, i.e. taking into account all the repetitions performed by patients, regardless of run type and ON/OFF status.

The ability to generate FOG episodes between different pathway modalities will be analyzed by comparing, for each pathway type, the percentage of time in FOG assessed by the experts using a mixed model (fixed effect on patients and random effect on pathway type).