title: Effects of freezing of gait on postural motor learning in people with Parkinson's disease.
abstract: Protective postural responses, including stepping, to recover equilibrium are critical for fall prevention and are impaired in people with Parkinson's disease (PD) with freezing of gait (FoG). Improving protective postural responses through training may reduce falls in this population. However, motor learning, the basis of neurorehabilitation, is also impaired in people with PD and, in particular, people with PD who experience freezing. It is unknown whether people with PD who freeze can improve protective postural responses, and whether these improvements are similar to nonfreezers. Our goal was to assess whether people with freezing can improve protective postural responses and retain these improvements similarly to nonfreezers. Twenty-eight people with PD (13 freezers, 15 nonfreezers) were enrolled. Improvement in protective postural responses was assessed over the course of 25 forward and 25 backward support surface translations (delivered in pseudo-random order). Postural responses were re-assessed 24h later to determine whether improvements were retained. People who freeze did not improve or retain improvement in protective postural responses as well as nonfreezers in our primary outcome variable, center of mass (COM) displacement after perturbations (post hoc across group assessments: freezers- p=0.14 and nonfreezers- p=0.001, respectively). However, other protective stepping outcomes, including margin of stability, step length, and step time, improved similarly across groups. Significant improvements were retained in both groups. In conclusion, people with PD who freeze exhibited reduced ability to improve protective postural responses in some, but not all, outcome variables. Additional training may be necessary to improve protective postural responses in people with PD who freeze.
authors.affiliation: Veterans Affairs Salt Lake City Health Care System (VAPORHCS), Salt Lake City, UT, United States; Arizona State University, Program in Exercise Science and Health Promotion, Phoenix, AZ, United States. Electronic address: dspeterson8@gmail.com.
authors.forename: D S
authors.initials: DS
authors.lastname: Peterson
authors.affiliation: Veterans Affairs Portland Health Care System (VAPORHCS), Portland, OR, United States; Oregon Health & Science University, Department of Neurology, Portland, OR, United States.
authors.forename: F B
authors.initials: FB
authors.lastname: Horak
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D020233:Gait Disorders, Neurologic / Q000150:complications / Q000503:physiopathology* / Q000523:psychology* / Q000534:rehabilitation; D006801:Humans; D007858:Learning; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008568:Memory; D009043:Motor Activity; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000523:psychology* / Q000534:rehabilitation; D011187:Posture
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Parkinson’s disease; freezing of gait; motor learning; posture; stepping