Behavioral and neural correlates of imagined walking and walking-while-talking in the elderly

Human Brain Mapping

Volumn 35, Issue 8, 2014, Pages 4090-4104

  Blumen, Helena M ^a   Holtzer, Roee ^a,b   Brown, Lucy L ^a   Gazes, Yunglin ^c   Verghese, Joe ^a  

^a ALBERT EINSTEIN COLLEGE OF MEDICINE   (United States)

^b YESHIVA UNIVERSITY   (United States)

^c NewYork Presbyterian Hospital   (United States)

Author keywords

Dual task; FMRI and aging; Gait; Imagery

Indexed keywords

ADULT; AGED; ARTICLE; CEREBELLUM; CINGULATE GYRUS; COGNITION; FEMALE; FUNCTIONAL MAGNETIC RESONANCE IMAGING; GAIT; HUMAN; IMAGERY; IMAGINED WALKING; IMAGINED WALKING WHILE TALKING; INFERIOR FRONTAL GYRUS; INSULA; MALE; MIDDLE FRONTAL GYRUS; MIDDLE TEMPORAL GYRUS; NORMAL HUMAN; OCCIPITAL GYRUS; POSTCENTRAL GYRUS; POSTERIOR CINGULATE; PRECUNEUS; PRIORITY JOURNAL; SUPERIOR FRONTAL GYRUS; THALAMUS; WALKING; AGING; BRAIN; BRAIN MAPPING; IMAGINATION; KINESTHESIA; NEUROPSYCHOLOGICAL TEST; NUCLEAR MAGNETIC RESONANCE IMAGING; PHYSIOLOGY; SPEECH; VERY ELDERLY; VISION;

AGED; AGED, 80 AND OVER; AGING; BRAIN; BRAIN MAPPING; FEMALE; HUMANS; IMAGINATION; KINESTHESIS; MAGNETIC RESONANCE IMAGING; MALE; NEUROPSYCHOLOGICAL TESTS; SPEECH; VISUAL PERCEPTION; WALKING;

EID: 84904004477     PISSN: 10659471     EISSN: 10970193     Source Type: Journal    
DOI: 10.1002/hbm.22461     Document Type: Article

References (120)

1. Anderson WS, Lenz FA (2011): Review of motor and phantom-related imagery. Neuroreport 22:939-942.
2. Atkinson HH, Rosano C, Simonsick EM, Williamson JD, Davis C, Ambrosius WT, Rapp SR, Cesari M, Newman AB, Harris TB, Rubin SM, Yaffe K, Satterfield S, Kritchevsky SB (2007): Cognitive function, gait speed decline, and comorbidities: The health, aging and body composition study. J Gerontol A Biol Sci Med Sci 62:844-850.
3. Baddeley A (1996): Exploring the central executive. Q J Exp Psychol A 49:5-28.
4. Baddeley A (2001): Is working memory still working? Am Psychol 56:851-864.
5. Bakker M, Lange FP, Stevens JA, Toni I, Bloem BR (2007): Motor imagery of gait: A quantitative approach. Exp Brain Res 179:497-504.
6. Beauchet O, Annweiler C, Assal F, Bridenbaugh S, Herrmann FR, Kressig RW, Allali G (2010): Imagined Timed Up & Go test: a new tool to assess higher-level gait and balance disorders in older adults? J Neurol Sci 294:102-106.
7. Beauchet O, Fantino B, Allali G, Muir SW, Montero-Odasso M, Annweiler C (2011): Timed up and go test and risk of falls in older adults: A systematic review. J Nutr Health Aging 15:933-938.
8. Beurskens R, Bock O (2012): Age-related deficits of dual-task walking: A review. Neural Plast 2012:131608.
9. Blumen HM, Gazes Y, Habeck C, Kumar A, Steffener J, Rakitin BC, Stern Y (2011): Neural networks associated with the speed-accuracy tradeoff: Evidence from the response signal method. Behav Brain Res 224:397-402.
10. Bridenbaugh S, Beauchet O, Annweiler C, Allali G, Herrmann F, Kressig R (2013): Association between dual task-related decrease in walking speed and real versus imagined Timed Up and Go test performance. Aging Clin Exp Res 25:283-289.
11. Buracchio T, Dodge HH, Howieson D, Wasserman D, Kaye J (2010): The trajectory of gait speed preceding mild cognitive impairment. Arch Neurol 67:980-986.
12. Buschke H (1973): Selective reminding for analysis of memory and learning. J Verbal Learn Verbal Behav 12:543-550.
13. Buschke H, Kuslansky G, Katz M, Stewart WF, Sliwinski MJ, Eckholdt HM, Lipton RB (1999): Screening for dementia with the memory impairment screen. Neurology 52:231-238.
14. Cabeza R, Anderson ND, Locantore JK, McIntosh AR (2002): Aging gracefully: Compensatory brain activity in high-performing older adults. Neuroimage 17:1394-1402.
15. Cabeza R, Grady CL, Nyberg L, McIntosh AR, Tulving E, Kapur S, Jennings JM, Houle S, Craik FI (1997): Age-related differences in neural activity during memory encoding and retrieval: A positron emission tomography study. J Neurosci 17:391-400.
16. Cavanna AE, Trimble MR (2006): The precuneus: A review of its functional anatomy and behavioural correlates. Brain 129:564-583.
17. Colcombe SJ, Kramer AF, Erickson KI, Scalf P. (2005): The Implications of Cortical Recruitment and Brain Morphology for Individual Differences in Inhibitory Function in Aging Humans. Psychology and Aging 20:363-375.
18. Cremers J, Dessoullieres A, Garraux G (2012): Hemispheric specialization during mental imagery of brisk walking. Hum Brain Mapp 33:873-882.
19. Davidson PS, Troyer AK, Moscovitch M (2006): Frontal lobe contributions to recognition and recall: linking basic research with clinical evaluation and remediation. J Int Neuropsychol Soc 12:210-223.
20. Diedrichsen J, Balsters JH, Flavell J, Cussans E, Ramnani N (2009): A probabilistic MR atlas of the human cerebellum. Neuroimage 46:39-46.
21. Diedrichsen J, Maderwald S, Kuper M, Thurling M, Rabe K, Gizewski ER, Ladd ME, Timmann D (2011): Imaging the deep cerebellar nuclei: A probabilistic atlas and normalization procedure. Neuroimage 54:1786-1794.
22. Dunsky A, Dickstein R, Marcovitz E, Levy S, Deutsch JE (2008): Home-based motor imagery training for gait rehabilitation of people with chronic poststroke hemiparesis. Arch Phys Med Rehabil 89:1580-1588.
23. Eickhoff SB, Heim S, Zilles K, Amunts K (2006): Testing anatomically specified hypotheses in functional imaging using cytoarchitectonic maps. Neuroimage 32:570-582.
24. Eickhoff SB, Paus T, Caspers S, Grosbras MH, Evans AC, Zilles K, Amunts K (2007): Assignment of functional activations to probabilistic cytoarchitectonic areas revisited. Neuroimage 36:511-521.
25. Eickhoff SB, Stephan KE, Mohlberg H, Grefkes C, Fink GR, Amunts K, Zilles K (2005): A new SPM toolbox for combining probabilistic cytoarchitectonic maps and functional imaging data. Neuroimage 25:1325-1335.
26. Erickson KI, Colcombe SJ, Wadhwa R, Bherer L, Peterson MS, Scalf PE, Kim JS, Alvarado M, Kramer AF (2007): Training-induced functional activation changes in dual-task processing: An fMRI study. Cereb Cortex 17:192-204.
27. Friston KJ, Ashburner J, Frith CD, Poline JB, Heather JD, Frackowiak RSJ (1995): Spatial registration and normalization of images. Hum Brain Mapp 3:165-189.
28. Friston KJ, Holmes AP, Worsley KJ, Poline JP, Frith CD, Frackowiak RSJ (1994): Statistical parametric maps in functional imaging: A general linear approach. Hum Brain Mapp 2:189-210.
29. Galvin JE, Roe CM, Powlishta KK, Coats MA, Muich SJ, Grant E, Miller JP, Storandt M, Morris JC (2005): The AD8: a brief informant interview to detect dementia. Neurology 65:559-564.
30. Gazes Y, Rakitin BC, Habeck C, Steffener J, Stern Y (2012): Age differences of multivariate network expressions during task-switching and their associations with behavior. Neuropsychologia 50:3509-3518.
31. Grady CL, McIntosh AR, Rajah MN, Beig S, Craik FI (1999): The effects of age on the neural correlates of episodic encoding. Cereb Cortex 9:805-814.
32. Guillot A, Collet C, Nguyen VA, Malouin F, Richards C, Doyon J (2009): Brain activity during visual versus kinesthetic imagery: an fMRI study. Hum Brain Mapp 30:2157-2172.
33. Habas C, Kamdar N, Nguyen D, Prater K, Beckmann CF, Menon V, Greicius MD (2009): Distinct cerebellar contributions to intrinsic connectivity networks. J Neurosci 29:8586-8594.
34. Habeck C, Rakitin BC, Moeller J, Scarmeas N, Zarahn E, Brown T, Stern Y (2005): An event-related fMRI study of the neural networks underlying the encoding, maintenance, and retrieval phase in a delayed-match-to-sample task. Brain Res Cogn Brain Res 23:207-220.
35. Habeck C, Stern Y (2007): Neural network approaches and their reproducibility in the study of verbal working memory and Alzheimer's disease. Clin Neurosci Res 6:381-390.
36. Harada K, Shimada H, Sawyer P, Asakawa Y, Nihei K, Kaneya S, Furuna T, Ishizaki T, Yasumura S (2010): [Life-space of community-dwelling older adults using preventive health care services in Japan and the validity of composite scoring methods for assessment]. Nihon Koshu Eisei Zasshi 57:526-537.
37. Hartley AA (1992): Attention. In: Craik FIM, Salthouse TA, editors. Handbook of Aging and Cognition. Hillsdale, NJ: Erlbaum. pp 1-49.
38. Heremans E, Feys P, Nieuwboer A, Vercruysse S, Vandenberghe W, Sharma N, Helsen W (2011): Motor imagery ability in patients with early- and mid-stage Parkinson disease. Neurorehabil Neural Repair 25:168-77.
39. Holmes AP, Friston KJ (1998): Generalisability, random effects and population inference. Neuroimage 7:S754.
40. Holtzer R, Mahoney JR, Izzetoglu M, Izzetoglu K, Onaral B, Verghese J (2011): fNIRS study of walking and walking while talking in young and old individuals. J Gerontol A Biol Sci Med Sci 66:879-887.
41. Holtzer R, Mahoney JR, Verghese J (2013): Intraindividual Variability in Executive Functions but Not Speed of Processing or Conflict Resolution Predicts Performance Differences in Gait Speed in Older Adults. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. doi: 10.1093/gerona/glt180.
42. Holtzer R, Rakitin BC, Steffener J, Flynn J, Kumar A, Stern Y (2009): Age effects on load-dependent brain activations in working memory for novel material. Brain Res 1249:148-161.
43. Holtzer R, Stern Y, Rakitin BC (2004): Age-related differences in executive control of working memory. Mem Cognit 32:1333-1345.
44. Holtzer R, Stern Y, Rakitin BC (2005): Predicting age-related dual-task effects with individual differences on neuropsychological tests. Neuropsychology 19:18-27.
45. Holtzer R, Verghese J, Xue X, Lipton RB (2006): Cognitive processes related to gait velocity: Results from the Einstein Aging Study. Neuropsychology 20:215-223.
46. Holtzer R, Wang C, Lipton R, Verghese J (2012a): The protective effects of executive functions and episodic memory on gait speed decline in aging defined in the context of cognitive reserve. J Am Geriatr Soc 60:2093-2098.
47. Holtzer R, Wang C, Verghese J (2012b): The relationship between attention and gait in aging: Facts and fallacies. Motor Control 16:64-80.
48. Holtzer R, Wang C, Verghese J (2014): Performance variance on walking while talking tasks: theory, findings, and clinical implications. Age 36:373-381.
49. Jahn K, Deutschlander A, Stephan T, Kalla R, Wiesmann M, Strupp M, Brandt T (2008): Imaging human supraspinal locomotor centers in brainstem and cerebellum. Neuroimage 39:786-792.
50. Jahn K, Deutschlander A, Stephan T, Strupp M, Wiesmann M, Brandt T (2004): Brain activation patterns during imagined stance and locomotion in functional magnetic resonance imaging. Neuroimage 22:1722-1731.
51. Jeannerod M (1994): The representing brain: Neural correlates of motor intention and imagery. Behav Brain Sci 17:187-202.
52. Jeannerod M (2001): Neural simulation of action: A unifying mechanism for motor cognition. Neuroimage 14:S103-S109.
53. Kahneman D (1973): Attention and Effort. Englewood Cliffs. NJ: Prentice-Hall.
54. Katzman R, Brown T, Fuld P, Peck A, Schechter R, Schimmel H (1983): Validation of a short Orientation-Memory-Concentration Test of cognitive impairment. Am J Psychiatry 140:734-739.
55. Kim JS, Oh DW, Kim SY, Choi JD (2011): Visual and kinesthetic locomotor imagery training integrated with auditory step rhythm for walking performance of patients with chronic stroke. Clin Rehabil 25:134-145.
56. Krienen FM, Buckner RL (2009): Segregated fronto-cerebellar circuits revealed by intrinsic functional connectivity. Cereb Cortex 19:2485-2497.
57. Kwong KK, Belliveau JW, Chesler DA, Goldberg IE, Weisskoff RM, Poncelet BP, Kennedy DN, Hoppel BE, Cohen MS, Turner R (1992): Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation. Proc Natl Acad Sci USA 89:5675-5679.
58. la Fougere C, Zwergal A, Rominger A, Forster S, Fesl G, Dieterich M, Brandt T, Strupp M, Bartenstein P, Jahn K (2010): Real versus imagined locomotion: A [18F]-FDG PET-fMRI comparison. Neuroimage 50:1589-1598.
59. Lancaster JL, Rainey LH, Summerlin JL, Freitas CS, Fox PT, Evans AC, Toga AW, Mazziotta JC (1997): Automated labeling of the human brain: a preliminary report on the development and evaluation of a forward-transform method. Hum Brain Mapp 5:238-242.
60. Lancaster JL, Woldorff MG, Parsons LM, Liotti M, Freitas CS, Rainey L, Kochunov PV, Nickerson D, Mikiten SA, Fox PT (2000): Automated Talairach atlas labels for functional brain mapping. Hum Brain Mapp 10:120-131.
61. Leiner HC, Leiner AL, Dow RS (1986): Does the cerebellum contribute to mental skills? Behav Neurosci 100:443-454.
62. Li KZ, Lindenberger U, Freund AM, Baltes PB (2001): Walking while memorizing: Age-related differences in compensatory behavior. Psychol Sci 12:230-237.
63. Lindenberger U, Marsiske M, Baltes PB (2000): Memorizing while walking: Increase in dual-task costs from young adulthood to old age. Psychol Aging 15:417-436.
64. Lipton RB, Katz MJ, Kuslansky G, Sliwinski MJ, Stewart WF, Verghese J, Crystal HA, Buschke H (2003): Screening for dementia by telephone using the memory impairment screen. J Am Geriatr Soc 51:1382-1390.
65. Malouin F, Richards CL, Jackson PL, Dumas F, Doyon J (2003): Brain activations during motor imagery of locomotor-related tasks: A PET study. Hum Brain Mapp 19:47-62.
66. Marks DF (1973): Visual imagery differences in the recall of pictures. Br J Psychol 64:17-24.
67. Marks DF (1995): New directions for mental imagery research. J Mental Imagery 19:153-167.
68. Marquis S, Moore MM, Howieson DB, Sexton G, Payami H, Kaye JA, Camicioli R (2002): Independent predictors of cognitive decline in healthy elderly persons. Arch Neurol 59:601-606.
69. McDowd JM, Shaw RJ (2000): Attention. In: Craik FIM, Salthouse TA, editors. Handbook of Aging and Cognition. Mahwah, NJ: : Erlbaum. pp 221-292.
70. McIntosh AR, Bookstein FL, Haxby JV, Grady CL (1996): Spatial pattern analysis of functional brain images using partial least squares. Neuroimage 3:143-157.
71. McNorgan C (2012): A meta-analytic review of multisensory imagery identifies the neural correlates of modality-specific and modality-general imagery. Front Hum Neurosci 6:285.
72. Morris JC, Heyman A, Mohs RC, Hughes JP, van Belle G, Fillenbaum G, Mellits ED, Clark C (1989): The Consortium to Establish a Registry for Alzheimer's Disease (CERAD). Part I. Clinical and neuropsychological assessment of Alzheimer's disease. Neurology 39:1159-1165.
73. Moscovitch M (1995): Frontal lobes, memory, and aging. Ann NY Acad Sci 769:119-150.
74. Neider MB, Gaspar JG, McCarley JS, Crowell JA, Kaczmarski H, Kramer AF (2011): Walking and talking: Dual-task effects on street crossing behavior in older adults. Psychol Aging 26:260-268.
75. Newman AB, Simonsick EM, Naydeck BL, Boudreau RM, Kritchevsky SB, Nevitt MC, Pahor M, Satterfield S, Brach JS, Studenski SA, Harris TB (2006): Association of long-distance corridor walk performance with mortality, cardiovascular disease, mobility limitation, and disability. J Am Med Assoc 295:2018-2026.
76. Norman DA, Shallice T (1980): Attention to Action : Willed and Automatic Control of Behavior. La Jolla, CA: Center for Human Information Processing, University of California, San Diego.
77. O'Reilly JX, Beckmann CF, Tomassini V, Ramnani N, Johansen-Berg H (2010): Distinct and overlapping functional zones in the cerebellum defined by resting state functional connectivity. Cereb Cortex 20:953-965.
78. Ogawa S, Menon RS, Tank DW, Kim SG, Merkle H, Ellermann JM, Ugurbil K (1993): Functional brain mapping by blood oxygenation level-dependent contrast magnetic resonance imaging. A comparison of signal characteristics with a biophysical model. Biophys J 64:803-812.
79. Oldfield RC (1971): The assessment and analysis of handedness: The Edinburgh inventory. Neuropsychologia 9:97-113.
80. Pashler H (1984): Processing stages in overlapping tasks: Evidence for a central bottleneck. J Exp Psychol Hum Percept Perform 10:358-377.
81. Petersen RC (2004): Mild cognitive impairment as a diagnostic entity. J Intern Med 256:183-194.
82. Petersen RC, Roberts RO, Knopman DS, Boeve BF, Geda YE, Ivnik RJ, Smith GE, Jack CR Jr (2009): Mild cognitive impairment: ten years later. Arch Neurol 66:1447-1455.
83. Petersen RC, Smith GE, Waring SC, Ivnik RJ, Tangalos EG, Kokmen E (1999): Mild cognitive impairment: clinical characterization and outcome. Arch Neurol 56:303-308.
84. Reitan R (1978): Manual for Administration of Neuropsychological Test Batteries for Adults and Children: Tucson, AZ: Reitan Neuropsychology Laboratories.
85. Reuter-Lorenz PA, Jonides J, Smith EE, Hartley A, Miller A, Marshuetz C, Koeppe RA (2000): Age differences in the frontal lateralization of verbal and spatial working memory revealed by PET. J Cogn Neurosci 12:174-187.
86. Rorden C, Bonilha L, Fridriksson J, Bender B, Karnath HO (2012): Age-specific CT and MRI templates for spatial normalization. Neuroimage 61:957-965.
87. Schmahmann JD, Doyon J, McDonald D, Holmes C, Lavoie K, Hurwitz AS, Kabani N, Toga A, Evans A, Petrides M (1999): Three-dimensional MRI atlas of the human cerebellum in proportional stereotaxic space. Neuroimage 10:233-260.
88. Schmahmann JD, Sherman JC (1998): The cerebellar cognitive affective syndrome. Brain 121:561-579.
89. Schwenk M, Zieschang T, Oster P, Hauer K (2010): Dual-task performances can be improved in patients with dementia: a randomized controlled trial. Neurology 74:1961-1968.
90. Sheikh JI, Yesavage JA (1986): Geriatric Depression Scale (GDS): Recent evidence and development of a shorter version. Clin Gerontol J Aging Mental Health 5:165-173.
91. Shimamura AP, Janowsky JS, Squire LR (1990): Memory for the temporal order of events in patients with frontal lobe lesions and amnesic patients. Neuropsychologia 28:803-813.
92. Stelzel C, Brandt SA, Schubert T (2009): Neural mechanisms of concurrent stimulus processing in dual tasks. Neuroimage 48:237-248.
93. Stern Y, Habeck C, Moeller J, Scarmeas N, Anderson KE, Hilton HJ, Flynn J, Sackeim H, van Heertum R (2005): Brain networks associated with cognitive reserve in healthy young and old adults. Cereb Cortex 15:394-402.
94. Stern Y, Rakitin BC, Habeck C, Gazes Y, Steffener J, Kumar A, Reuben A (2012): Task difficulty modulates young-old differences in network expression. Brain Res 1435:130-145.
95. Stoodley CJ (2012): The cerebellum and cognition: Evidence from functional imaging studies. Cerebellum 11:352-365.
96. Stoodley CJ, Schmahmann JD (2009): Functional topography in the human cerebellum: A meta-analysis of neuroimaging studies. Neuroimage 44:489-501.
97. Szameitat AJ, Schubert T, Müller K, von Cramon DY (2002): Localization of Executive Functions in Dual-Task Performance with fMRI. J Cogn Neurosci 14:1184-1199.
98. Tamir R, Dickstein R, Huberman M (2007): Integration of motor imagery and physical practice in group treatment applied to subjects with Parkinson's disease. Neurorehabil Neural Repair 21:68-75.
99. van der Meulen M, Allali G, Rieger SW, Assal F, Vuilleumier P (2012): The influence of individual motor imagery ability on cerebral recruitment during gait imagery. Human Brain Mapping.
100. Verghese J, Buschke H, Viola L, Katz M, Hall C, Kuslansky G, Lipton R (2002a): Validity of divided attention tasks in predicting falls in older individuals: A preliminary study. J Am Geriatr Soc 50:1572-1576.
101. Verghese J, Holtzer R (2010): Walking the walk while talking: cognitive therapy for mobility in dementia? Neurology 74:1938-1939.
102. Verghese J, Holtzer R, Lipton RB, Wang C (2012): Mobility stress test approach to predicting frailty, disability, and mortality in high-functioning older adults. J Am Geriatr Soc 60:1901-1905.
103. Verghese J, Katz MJ, Derby CA, Kuslansky G, Hall CB, Lipton RB (2004): Reliability and validity of a telephone-based mobility assessment questionnaire. Age Ageing 33:628-632.
104. Verghese J, Kuslansky G, Holtzer R, Katz M, Xue X, Buschke H, Pahor M (2007a): Walking while talking: effect of task prioritization in the elderly. Arch Phys Med Rehabil 88:50-53.
105. Verghese J, LeValley A, Hall CB, Katz MJ, Ambrose AF, Lipton RB (2006): Epidemiology of gait disorders in community-residing older adults. J Am Geriatr Soc 54:255-261.
106. Verghese J, Lipton RB, Hall CB, Kuslansky G, Katz MJ, Buschke H (2002b): Abnormality of gait as a predictor of non-Alzheimer's dementia. New Engl J Med 347:1761-1768.
107. Verghese J, Mahoney J, Ambrose AF, Wang C, Holtzer R (2010): Effect of cognitive remediation on gait in sedentary seniors. J Gerontol A Biol Sci Med Sci 65:1338-1343.
108. Verghese J, Robbins M, Holtzer R, Zimmerman M, Wang C, Xue X, Lipton RB (2008): Gait dysfunction in mild cognitive impairment syndromes. J Am Geriatr Soc 56:1244-1251.
109. Verghese J, Wang C, Lipton RB, Holtzer R, Xue X (2007b): Quantitative gait dysfunction and risk of cognitive decline and dementia. J Neurol Neurosurg Psychiatry 78:929-935.
110. Verhaeghen P, Steitz DW, Sliwinski MJ, Cerella J (2003): Aging and dual-task performance: A meta-analysis. Psychol Aging 18:443-460.
111. Verma R, Arya KN, Garg RK, Singh T (2011): Task-oriented circuit class training program with motor imagery for gait rehabilitation in poststroke patients: A randomized controlled trial. Top Stroke Rehabil 18(Suppl 1):620-632.
112. Waite LM, Grayson DA, Piguet O, Creasey H, Bennett HP, Broe GA (2005): Gait slowing as a predictor of incident dementia: 6-year longitudinal data from the Sydney Older Persons Study. J Neurol Sci 230:89-93.
113. Wang J, Wai Y, Weng Y, Ng K, Huang YZ, Ying L, Liu H, Wang C (2009): Functional MRI in the assessment of cortical activation during gait-related imaginary tasks. J Neural Transm 116:1087-1092.
114. Wang L, Larson EB, Bowen JD, van Belle G (2006): Performance-based physical function and future dementia in older people. Arch Intern Med 166:1115-1120.
115. Watson NL, Rosano C, Boudreau RM, Simonsick EM, Ferrucci L, Sutton-Tyrrell K, Hardy SE, Atkinson HH, Yaffe K, Satterfield S, Harris TB, Newman AB (2010): Executive function, memory, and gait speed decline in well-functioning older adults. J Gerontol A Biol Sci Med Sci 65:1093-1100.
116. West RL (1996): An application of prefrontal cortex function theory to cognitive aging. Psychol Bull 120:272-292.
117. Worsley KJ, Poline JB, Friston KJ, Evans AC (1997): Characterizing the response of PET and fMRI data using multivariate linear models. Neuroimage 6:305-319.
118. Yesavage JA (1988): Geriatric depression scale. Psychopharmacol Bull 24:709-711.
119. Yesavage JA, Brink TL, Rose TL, Lum O, Huang V, Adey M, Leirer VO (1982): Development and validation of a geriatric depression screening scale: A preliminary report. J Psychiatr Res 17:37-49.
120. Zwergal A, Linn J, Xiong G, Brandt T, Strupp M, Jahn K (2012): Aging of human supraspinal locomotor and postural control in fMRI. Neurobiol Aging 33:1073-1084.