Patients’ clinical features.
FOG–P: Patients with freezing of gait (FOG) with little to no parkinsonism.
PD–FOG: Patients with Parkinson’s disease without FOG.
FOG onset: The time from symptom onset to FOG onset.
UPDRS: Unified Parkinson’s disease rating scale.
Axial: The total of standing, posture, gait and postural instability items.
Upper limb movement: The total of upper limb repetitive movement items.
Lower limb movement: The total of lower limb repetitive movement items.
Rigidity: The total rigidity score for the neck and limbs.
Tremor: The total tremor score for the neck and limbs.
NFOG-Q: New freezing of gait questionnaire.