Background/Objective: The aim of this study was to analyze the effects of dual tasking on obstacle crossing during walking by individuals with Alzheimer's disease (AD) and by healthy older people. Methods: Thirty four elderly individuals (16 healthy subjects and 18 individuals with AD) were recruited to participate in this study. Three AD individuals and one control participant were excluded due to exclusion criteria. The participants were instructed to walk barefoot at their own speed along an 8 m long pathway. Each participant performed five trials for each condition (unobstructed walking, unobstructed walking with dual tasking, and obstacle crossing during walking with dual tasking). The trials were completely randomized for each participant. The mid-pathway stride was measured in the unobstructed walking trials and the stride that occurred during the obstacle avoidance was measured in the trials that involved obstacle crossing. Results/Conclusion: The behavior of the healthy elderly subjects and individuals with AD was similar for obstacle crossing during walking with dual tasking. Both groups used the 'posture first' strategy to prioritize stability and showed decreased attention to executive tasking while walking. Additionally, AD had a strong influence on the modifications that are made by the elderly while walking under different walking conditions.432435441Maquet, D., Lekeu, F., Warzee, E., Gillain, S., Wojtasik, V., Salmon, E., Petermans, J., Croisier, J.L., Gait analysis inelderly adult patients with mild cognitive impairment andpatients with mild Alzheimer's disease: Simple versus dualtask: A preliminary report (2010) Clin Physiol Funct Imaging, 30, pp. 51-56Sheridan, P.L., Solomont, J., Kowall, N., Hausdorff, J.M., Influence of executive function on locomotor function:Divided attention increases gait variability in Alzheimer'sdisease (2003) J Am Geriatr Soc, 51, pp. 1633-1637Orcioli-Silva, D., Simieli, L., Barbieri, F.A., Stella, F., Gobbi, L.T., Adaptive walking in Alzheimer's disease (2012) Int J Alzheimers Dis, 2012, p. 674589Coelho, F.G., Stella, F., De Andrade, L.P., Barbieri, F.A., Santos-Galduroz, R.F., Gobbi, S., Costa, J.L., Gobbi, L.T., Gait andrisk of falls associated with frontal cognitive functions at differentstages of Alzheimer's disease (2012) Neuropsychol Dev CognB Aging Neuropsychol Cogn, 19, pp. 644-656Persad, C.C., Jones, J.L., Ashton-Miller, J.A., Alexander, N.B., Giordani, B., Executive function and gait in older adultswith cognitive impairment (2008) J Gerontol A Biol Sci Med Sci, 63, pp. 1350-1355Cocchini, G., Della Sala, S., Logie, R.H., Pagani, R., Sacco, L., Spinnler, H., Dual task effects of walking when talkingin Alzheimer's disease (2004) Rev Neurol (Paris), 160, pp. 74-80Imamura, T., Hirono, N., Hashimoto, M., Kazui, H., Tanimukai, S., Hanihara, T., Takahara, A., Mori, E., Fall-related injuries indementia with Lewy bodies (DLB) and Alzheimer's disease (2000) Eur J Neurol, 7, pp. 77-79Nadkarni, N.K., Mawji, E., McIlroy, W.E., Black, S.E., Spatialand temporal gait parameters in Alzheimer's disease andaging (2009) Gait Posture, 30, pp. 452-454Suttanon, P., Hill, K.D., Said, C.M., Logiudice, D., Lautenschlager, N.T., Dodd, K.J., Balance and mobility dysfunction andfalls risk in older people with mild to moderate Alzheimerdisease (2012) Am J Phys Med Rehabil, 91, pp. 12-23Campbell, A.J., Borrie, M.J., Spears, G.F., Jackson, S.L., Brown, J.S., Fitzgerald, J.L., Circumstances and consequences of fallsexperienced by a community population 70 years and overduring a prospective study (1990) Age Ageing, 19, pp. 136-141Stolze, H., Klebe, S., Zechlin, C., Baecker, C., Friege, L., Deuschl, G., Falls in frequent neurological diseases-prevalence, risk factors and aetiology (2004) J Neurol, 251, pp. 79-84Vitorio, R., Pieruccini-Faria, F., Stella, F., Gobbi, S., Gobbi, L.T., Effects of obstacle height on obstacle crossing in mildParkinson's disease (2010) Gait Posture, 31, pp. 143-146Patla, A.E., Strategies for dynamic stability during adaptivehuman locomotion (2003) IEEE Eng Med Biol Mag, 22, pp. 48-52Chou, L.S., Kaufman, K.R., Hahn, M.E., Brey, R.H., Mediolateralmotion of the center of mass during obstacle crossingdistinguishes elderly individuals with imbalance (2003) Gait Posture, 18, pp. 125-133Alexander, N.B., Mollo, J.M., Giordani, B., Ashton-Miller, J.A., Schultz, A.B., Grunawalt, J.A., Foster, N.L., Maintenance ofbalance, gait patterns, and obstacle clearance in Alzheimer'sdisease (1995) Neurology, 45, pp. 908-914Ble, A., Volpato, S., Zuliani, G., Guralnik, J.M., Bandinelli, S., Lauretani, F., Bartali, B., Ferrucci, L., Executive function correlates with walking speed inolder persons: The InCHIANTI study (2005) J Am Geriatr Soc, 53, pp. 410-415Persad, C.C., Giordani, B., Chen, H.C., Ashton-Miller, J.A., Alexander, N.B., Wilson, C.S., Berent, S., Schultz, A.B., Neuropsychological predictors of complex obstacle avoidancein healthy older adults (1995) J Gerontol B Psychol Sci SocSci, 50, pp. P272-P277Yogev-Seligmann, G., Hausdorff, J.M., Giladi, N., Do wealways prioritize balance when walking? Towards an integratedmodel of task prioritization (2012) Mov Disord, 27, pp. 765-770Shumway-Cook, A., Woollacott, M., Kerns, K.A., Baldwin, M., The effects of two types of cognitive tasks on posturalstability in older adults with and without a history offalls (1997) J Gerontol A Biol Sci Med Sci, 52, pp. M232-M240Williams, L.M., An integrative neuroscience model of "0 significance "0 processing (2006) J Integr Neurosci, 5, pp. 1-47Sheridan, P.L., Hausdorff, J.M., The role of higher-levelcognitive function in gait: Executive dysfunction contributesto fall risk in Alzheimer's disease (2007) Dement Geriatr Cogn Disord, 24, pp. 125-137(2002) ManualDiagnóstico e Estatístico de Transtornos Mentais, , American Psychiatric AssociationHughes, C.P., Berg, L., Danziger, W.L., Coben, L.A., Martin, R.L., A new clinical scale for the staging of dementia (1982) Br J Psychiatry, 140, pp. 566-572Cummings, J.L., Mega, M., Gray, K., Rosenberg-Thompson, S., Carusi, D.A., Gornbein, J., The Neuropsychiatric Inventory: Comprehensive assessment of psychopathology indementia (1994) Neurology, 44, pp. 2308-2314Folstein, M.F., Folstein, S.E., McHugh, P.R., 0 Mini-mentalstate "0 . A practical method for grading the cognitive state ofpatients for the clinician (1975) J Psychiatr Res, 12, pp. 189-198Montano, M.B., Ramos, L.R., Validity of the portugueseversion of clinical dementia rating (2005) Rev Saude Publica, 39, pp. 912-917Royall, D.R., Cordes, J.A., Polk, M., CLOX: An executiveclock drawing task (1998) J Neurol Neurosurg Psychiatry, 64, pp. 588-594Dubois, B., Slachevsky, A., Litvan, I., Pillon, B., The FAB:A frontal assessment battery at bedside (2000) Neurology, 55, pp. 1621-1626Beato, R.G., Nitrini, R., Formigoni, A.P., Caramelli, P., Brazilian version of the Frontal Assessment Battery (FAB) :Preliminary data on administration to healthy elderly (2007) Dementia Neuropsychol, 1, p. 7Camicioli, R., Bouchard, T., Licis, L., Dual-tasks and walking fast: Relationship to extra-pyramidal signs in advanced Alzheimer disease (2006) J Neurol Sci, 248, pp. 205-209Hausdorff, J.M., Cudkowicz, M.E., Firtion, R., Wei, J.Y., Goldberger, A.L., Gait variability and basal ganglia disorders:Stride-to-stride variations of gait cycle timing in Parkinson'sdisease and Huntington's disease (1998) Mov Disord, 13, pp. 428-437Brauer, S.G., Woollacott, M., Shumway-Cook, A., Theinfluence of a concurrent cognitive task on the compensatorystepping response to a perturbation in balance-impaired andhealthy elders (2002) Gait Posture, 15, pp. 83-93Jahanshahi, M., Willed action and its impairments (1998) Cogn Neuropsychol, 15, pp. 483-533Barbieri, F.A., Santos Dos, P.C., Vitorio, R., Van Jh, D., Gobbi, L.T., Effect of muscle fatigue and physical activity levelin motor control of the gait of young adults (2013) Gait Posture, 38, pp. 702-707Beauchet, O., Kressig, R.W., Najafi, B., Aminian, K., Dubost, V., Mourey, F., Age-related decline of gait control under adual-task condition (2003) J Am Geriatr Soc, 51, pp. 1187-1188Pettersson, A.F., Olsson, E., Wahlund, L.O., Effect of divided attention on gait in subjects with and without cognitive impairment (2007) J Geriatr Psychiatry Neurol, 20, pp. 58-62Van Mb, I., Munneke, M., Esselink, R.A., Benraad, C.E., Olde Rikkert, M.G., Gait velocity and the Timed-Up-and-Go test were sensitive to changes in mobility in frail elderlypatients (2008) J Clin Epidemiol, 61, pp. 186-191Burns, J.M., Galvin, J.E., Roe, C.M., Morris, J.C., McKeel, D.W., The pathology of the substantia nigra in Alzheimerdisease with extrapyramidal signs (2005) Neurology, 64, pp. 1397-1403De Jo, L., Ortiz, K.Z., Campanha, A.C., Bertolucci, P.H., MinettTS (2011) Microlinguistic aspects of the oral narrative inpatients with Alzheimer's disease Int Psychogeriatr, 23, pp. 404-412Christofoletti, G., Oliani, M.M., Gobbi, L.T., Gobbi, S., Stella, F., Risco de quedas em idosos com Doencą de Parkinsone Demência de Alzheimer: Um estudo transversal (2006) Rev Bras Fisioter, 10, pp. 429-433