title: Age effects on mediolateral balance control.
abstract: BACKGROUND
  Age-related balance impairments, particularly in mediolateral direction (ML) may cause falls. Sufficiently sensitive and reliable ML balance tests are, however, lacking. This study is aimed to determine (1) the effect of age on and (2) the reliability of ML balance performance using Center of Mass (CoM) tracking.
  
  
  METHODS
  Balance performance of 19 young (26±3 years) and 19 older (72±5 years) adults on ML-CoM tracking tasks was compared. Subjects tracked predictable and unpredictable target displacements at increasing frequencies with their CoM by shifting their weight sideward. Phase-shift (response delay) and gain (amplitude difference) between the CoM and target in the frequency domain were used to quantify performance. Thirteen older and all young adults were reassessed to determine reliability of balance performance measures. In addition, all older adults performed a series of clinical balance tests and conventional posturography was done in a sub-sample.
  
  
  RESULTS
  Phase-shift and gain dropped below pre-determined thresholds (-90 degrees and 0.5) at lower frequencies in the older adults and were even lower below these frequencies than in young adults. Performance measures showed good to excellent reliability in both groups. All clinical scores were close to the maximum and no age effect was found using posturography. ML balance performance measures exhibited small but systematic between-session differences indicative of learning.
  
  
  CONCLUSIONS
  The ability to accurately perform ML-CoM tracking deteriorates with age. ML-CoM tracking tasks form a reliable tool to assess ML balance in young and older adults and are more sensitive to age-related impairment than posturography and clinical tests.
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: L Eduardo
authors.initials: LE
authors.lastname: Cofré Lizama
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Pijnappels
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Gert H
authors.initials: GH
authors.lastname: Faber
authors.affiliation: College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Reeves
authors.affiliation: Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Sabine M
authors.initials: SM
authors.lastname: Verschueren
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieën
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D004856:Postural Balance; D013647:Task Performance and Analysis; D055815:Young Adult