title: Gait and balance disorders in Parkinson's disease: impaired active braking of the fall of centre of gravity.
abstract: Gait and balance disorders are common in Parkinson's disease (PD), but its pathophysiology is still poorly understood. Step length, antero-posterior, and vertical velocities of the center of gravity (CG) during gait initiation were analyzed in 32 controls and 32 PD patients, with and without levodopa, using a force platform. Brain volumes and mesencephalic surface area were measured in PD patients. During the swing limb period, controls showed a fall in the CG, which was reversed before foot-contact indicating active braking of the CG fall. In PD patients, without levodopa, step length and velocity were significantly reduced and no braking occurred before foot-contact in 22 patients. With levodopa, step length and velocity increased in all patients and 7 patients improved their braking capacity. PD patients with normal braking (n = 17) had significantly lower gait and balance disorder scores and higher normalized-mesencephalic surface areas compared to patients with impaired braking (n = 15). The decreased step length and velocity, characteristic of PD, mainly result from degeneration of central dopaminergic systems. The markedly decreased braking capacity observed in half the PD patients contributes to their gait disorders and postural instability, perhaps as a result of nondopaminergic lesions, possibly at the mesencephalic level.
authors.affiliation: Fédération des Maladies du Système Nerveux, Centre d'Investigation Clinique, Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Chastan
authors.forename: Manh Cuong
authors.initials: MC
authors.lastname: Do
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bonneville
authors.forename: Frédéric
authors.initials: F
authors.lastname: Torny
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bloch
authors.forename: G W Max
authors.initials: GW
authors.lastname: Westby
authors.forename: Didier
authors.initials: D
authors.lastname: Dormont
authors.forename: Yves
authors.initials: Y
authors.lastname: Agid
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Welter
mesh_terms: D000978:Antiparkinson Agents / Q000494:pharmacology / Q000627:therapeutic use; D001479:Basal Ganglia / Q000473:pathology / Q000503:physiopathology; D001696:Biomechanical Phenomena; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D004298:Dopamine / Q000502:physiology; D005260:Female; D020235:Gait Apraxia / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D006112:Gravitation; D006801:Humans; D007980:Levodopa / Q000494:pharmacology / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D009929:Organ Size; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology*; D004856:Postural Balance / Q000187:drug effects / Q000502:physiology*; D012678:Sensation Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa; D004298:Dopamine