Relationship between going outdoors daily and activation of the prefrontal cortex during verbal fluency tasks (VFTs) among older adults: A near-infrared spectroscopy study Hyuma Makizako a,b, *, Takehiko Doi a , Hiroyuki Shimada a , Hyuntae Park c , Kazuki Uemura a,b , Daisuke Yoshida a , Kota Tsutsumimoto a , Yuya Anan a , Takao Suzuki d a Section for Health Promotion, Department for Research and Development to Support Independent Life of Elderly, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka-machi, Obu, Aichi 474-8511, Japan b Japan Society for the Promotion of Science, Sumitomo-Ichibancho FS Bldg., 8 Ichibancho, Chiyoda-ku, Tokyo 102-8472, Japan c Section for Physical Functioning Activation, Department of Functioning Activation, Center for Gerontology and Social Science, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka-machi, Obu, Aichi 474-8511, Japan d Research Institute, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka-machi, Obu, Aichi 474-8511, Japan 1. Introduction For older people, getting outdoors requires a certain level of physical and cognitive functioning. A low frequency of going out has been found to predict functional and intellectual decline among frail older adults, whereas going out frequently corre- sponded with improvement of baseline self-efficacy for both daily activities and health promotion (Kono, Kai, Sakato, & Rubenstein, 2004). In a recent longitudinal study, with a mean follow-up of 4.4 years, constricted living space was found to lead to decreased physical activity and social engagement, and was associated with increased risk of Alzheimer disease (AD), mild cognitive im- pairment (MCI), and a faster rate of global cognitive decline among older adults (James, Boyle, Buchman, Barnes, & Bennett, 2011). Thus, going out into the life-space seems to play an important role in maintaining physical and cognitive function among older adults. Older adults with cognitive impairment, such as AD patients, demonstrate diminished activation of the prefrontal cortex during cognitive tasks compared to those who are cognitively healthy (Herrmann, Langer, Jacob, Ehlis, & Fallgatter, 2008; Li, Zheng, Wang, & Gui, 2009; Richter, Herrmann, Ehlis, Plichta, & Fallgatter, 2007). Cognitive decline is thought to be a consequence of neurodegeneration in the brain, and abnormal activation during cognitive task performance has been found to precede decline of cognitive function (Clark et al., 2012; O’Brien et al., 2010). A previous functional neuroimaging study used near-infrared spectroscopy (NIRS) to investigate the oxygenation of brain tissue during the VFT in dementia patients (Herrmann et al., 2008). The results revealed that dementia patients exhibited reduced brain activation during VFT performance, as indicated by significantly lower oxygenated hemoglobin (oxy-Hb) levels compared to control subjects. The VFT is a neuropsychological task with category-fluency and letter-fluency versions. The VFT allows an Archives of Gerontology and Geriatrics 56 (2013) 118–123 A R T I C L E I N F O Article history: Received 10 April 2012 Received in revised form 28 August 2012 Accepted 30 August 2012 Available online 17 September 2012 Keywords: Aging Cerebral oxygenation Life-space Cognition A B S T R A C T This study sought to investigate the relationship between going outdoor daily and prefrontal cortex activation during execution of the VFT using near-infrared spectroscopy (NIRS) in community-dwelling older adults. Blood oxygenation changes in left and right prefrontal cortices were measured in twenty older adults (mean age 76.1 Æ 6.7 years) by NIRS during VFT performance. In this task, participants were required to pronounce as many nouns as possible beginning with the letters ‘‘Shi,’’ ‘‘I,’’ and ‘‘Re.’’ Changes in oxygenated hemoglobin (oxy-Hb) levels during the VFT were compared between two groups defined by the frequency of going outdoors: daily or non-daily within a week. Participants in both groups exhibited significantly increased oxy-Hb levels in the left and right prefrontal cortices during the VFT compared to a resting baseline condition. After controlling for age and gender, there were significant group-by-condition interactions on oxy-Hb levels with less activation during the execution of the VFT over both cortices in the non-daily group (left: F = 4.76, p = 0.04; right: F = 6.32, p = 0.02). These findings indicate that going outdoors daily is associated with increased activation in the prefrontal cortices during VFT performance in community-dwelling older adults. ß 2012 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Section for Health Promotion, Department of Health and Medical Care, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka-machi, Obu, Aichi 474-8551, Japan. Tel.: +81 562 44 5651x5082; fax: +81 562 46 8294. E-mail address: makizako@ncgg.go.jp (H. Makizako). Contents lists available at SciVerse ScienceDirect Archives of Gerontology and Geriatrics jo ur n al ho mep ag e: www .elsevier .c om /lo cate/ar c hg er 0167-4943/$ – see front matter ß 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.archger.2012.08.017