title: Poor trail making test performance is directly associated with altered dual task prioritization in the elderly--baseline results from the TREND study.
abstract: BACKGROUND
  Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance--which specifically measures cognitive flexibility and working memory--and dual task costs, a measure of prioritization.
  
  
  RESULTS
  Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders), 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A). The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range -6 to 58%) compared to the good performers (17%; -16 to 43%; p<0.001). To the contrary, the proportion of the poor TMT performance group that made calculation errors under the dual tasking situation was lower than under the single task situation, but higher in the good TMT performance group (poor performers, -1.6%; good performers, +3%; p = 0.035).
  
  
  CONCLUSIONS
  Under most challenging conditions, the elderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive flexibility and working memory are directly associated with altered prioritization.
authors: Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, Center of Neurology, University of Tuebingen, Tuebingen, Germany.
authors: Markus A
authors: MA
authors: Hobert
authors: Raphael
authors: R
authors: Niebler
authors: Sinja I
authors: SI
authors: Meyer
authors: Kathrin
authors: K
authors: Brockmann
authors: Clemens
authors: C
authors: Becker
authors: Heiko
authors: H
authors: Huber
authors: Alexandra
authors: A
authors: Gaenslen
authors: Jana
authors: J
authors: Godau
authors: Gerhard W
authors: GW
authors: Eschweiler
authors: Daniela
authors: D
authors: Berg
authors: Walter
authors: W
authors: Maetzler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003071:Cognition; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000175:diagnosis; D011597:Psychomotor Performance; D013647:Task Performance and Analysis; D014145:Trail Making Test; D016138:Walking / Q000502:physiology