title: Upper-Extremity Dual-Task Function: An Innovative Method to Assess Cognitive Impairment in Older Adults.
abstract: BACKGROUND
  Difficulties in orchestrating simultaneous tasks (i.e., dual-tasking) have been associated with cognitive impairments in older adults. Gait tests have been commonly used as the motor task component for dual-task assessments; however, many older adults have mobility impairments or there is a lack of space in busy clinical settings. We assessed an upper-extremity function (UEF) test as an alternative motor task to study the dual-task motor performance in older adults.
  
  
  METHODS
  Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal cognitive assessment (MoCA). Participants performed repetitive elbow flexion with their maximum pace, once single-task, and once while counting backward by one (dual-task). Single- and dual-task gait tests were also performed with normal speed. Three-dimensional kinematics was measured both from upper-extremity and lower-extremity using wearable sensors to determine UEF and gait parameters. Parameters were compared between the cognitively impaired and healthy groups using analysis of variance tests, while controlling for age, gender, and body mass index (BMI). Correlations between UEF and gait parameters for dual-task and dual-task cost were assessed using linear regression models.
  
  
  RESULTS
  Sixty-seven older adults were recruited (age = 83 ± 10 years). Based on MoCA, 10 (15%) were cognitively impaired. While no significant differences were observed in the single-task condition, within the dual-task condition, the cognitively impaired group showed significantly less arm flexion speed (62%, d = 1.51, p = 0.02) and range of motion (27%, d = 0.93, p = 0.04), and higher speed variability (88%, d = 1.82, p < 0.0001) compared to the cognitively intact group, when adjusted with age, gender, and BMI. Significant correlations were observed between UEF speed parameters and gait stride velocity for dual-task condition (r = 0.55, p < 0.0001) and dual-task cost (r = 0.28, p = 0.03).
  
  
  CONCLUSIONS
  We introduced a novel test for assessing dual-task performance in older adults that lasts 20 s and is based on upper-extremity function. Our results confirm significant associations between upper-extremity speed, range of motion, and speed variability with both the MoCA score and the gait performance within the dual-task condition.
authors.affiliation: Arizona Center on Aging, Department of Medicine, College of Medicine, University of Arizona, Tucson AZ, USA.
authors.forename: Nima
authors.initials: N
authors.lastname: Toosizadeh
authors.affiliation: Arizona Center on Aging, Department of Medicine, College of Medicine, University of Arizona, TucsonAZ, USA; Interdisciplinary Consortium on Advanced Motion Performance, Department of Surgery, College of Medicine, University of Arizona, TucsonAZ, USA; Department of Neurology, College of Medicine, University of Arizona, TucsonAZ, USA; Department of Biomedical Engineering, University of Arizona, TucsonAZ, USA.
authors.forename: Bijan
authors.initials: B
authors.lastname: Najafi
authors.affiliation: Department of Neurology, College of Medicine, University of Arizona, TucsonAZ, USA; Banner Sun Health Research Institute, Sun CityAZ, USA; Banner Alzheimer's Institute, University of Arizona, TucsonAZ, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Reiman
authors.affiliation: Department of Biomedical Engineering, University of Arizona, Tucson AZ, USA.
authors.forename: Reine M
authors.initials: RM
authors.lastname: Mager
authors.affiliation: Department of Biomedical Engineering, University of Arizona, Tucson AZ, USA.
authors.forename: Jaimeson K
authors.initials: JK
authors.lastname: Veldhuizen
authors.affiliation: Banner Sun Health Research Institute, Sun CityAZ, USA; Banner Alzheimer's Institute, University of Arizona, TucsonAZ, USA.
authors.forename: Kathy
authors.initials: K
authors.lastname: O'Connor
authors.affiliation: Banner Sun Health Research Institute, Sun CityAZ, USA; Banner Alzheimer's Institute, University of Arizona, TucsonAZ, USA; Department of Neurology, University of Utah, Salt Lake CityUT, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Zamrini
authors.affiliation: Arizona Center on Aging, Department of Medicine, College of Medicine, University of Arizona, TucsonAZ, USA; Interdisciplinary Consortium on Advanced Motion Performance, Department of Surgery, College of Medicine, University of Arizona, TucsonAZ, USA; Department of Biomedical Engineering, University of Arizona, TucsonAZ, USA; Banner Alzheimer's Institute, University of Arizona, TucsonAZ, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Mohler
keywords: Alzheimer’s disease; cognition; dual-task cost; mild cognitive impairment; upper-limb movements