Associations between quantitative mobility measures derived from components of conventional mobility testing and Parkinsonian gait in older adults.
OBJECTIVE
To provide objective measures which characterize mobility in older adults assessed in the community setting and to examine the extent to which these measures are associated with parkinsonian gait.


METHODS
During conventional mobility testing in the community-setting, 351 ambulatory non-demented Memory and Aging Project participants wore a belt with a whole body sensor that recorded both acceleration and angular velocity in 3 directions. We used measures derived from these recordings to quantify 5 subtasks including a) walking, b) transition from sit to stand, c) transition from stand to sit, d) turning and e) standing posture. Parkinsonian gait and other mild parkinsonian signs were assessed with a modified version of the original Unified Parkinson's Disease Rating Scale (mUPDRS).


RESULTS
In a series of separate regression models which adjusted for age and sex, all 5 mobility subtask measures were associated with parkinsonian gait and accounted for 2% to 32% of its variance. When all 5 subtask measures were considered in a single model, backward elimination showed that measures of walking sit to stand and turning showed independent associations with parkinsonian gait and together accounted for more than 35% of its variance. Cross-validation using data from a 2(nd) group of 258 older adults showed similar results. In similar analyses, only walking was associated with bradykinesia and sway with tremor.


CONCLUSIONS
Quantitative mobility subtask measures vary in their associations with parkinsonian gait scores and other parkinsonian signs in older adults. Quantifying the different facets of mobility has the potential to facilitate the clinical characterization and understanding the biologic basis for impaired mobility in older adults.
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
Aron S
AS
Buchman
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
Sue E
SE
Leurgans
Laboratory for Gait and Neurodynamics, Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
Aner
A
Weiss
Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America ; Harvard Medical School, Boston, Massachusetts, United States of America.
Veronique
V
Vanderhorst
Laboratory for Gait and Neurodynamics, Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
Anat
A
Mirelman
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, Illinois, United States of America.
Robert
R
Dawe
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
Lisa L
LL
Barnes
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
Robert S
RS
Wilson
Laboratory for Gait and Neurodynamics, Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel ; Harvard Medical School, Boston, Massachusetts, United States of America ; Department of Physical Therapy, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.
Jeffrey M
JM
Hausdorff
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America ; Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, United States of America.
David A
DA
Bennett
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005684:Gait; D006801:Humans; D018476:Hypokinesia; D008124:Locomotion; D008297:Male; D009127:Muscle Rigidity; D010300:Parkinson Disease / Q000453:epidemiology* / Q000503:physiopathology*; D014202:Tremor