ORIGINAL RESEARCH—ANATOMY/PHYSIOLOGY Induction of Sexual Arousal in Women Under Conditions of Institutional and Ambulatory Laboratory Circumstances: A Comparative Study Jos Bloemers, MSc,* Jeroen Gerritsen, MSc,* Richard Bults, MSc, † Hans Koppeschaar, MD, PhD,* Walter Everaerd, PhD, ‡ Berend Olivier, PhD, §¶ and Adriaan Tuiten, PhD* § *Emotional Brain B.V. (EB), Almere, The Netherlands; † MobiHealth B.V., Enschede, The Netherlands, ‡ Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands; § Utrecht Institute for Pharmaceutical Sciences and Rudolf Magnus Institute of Neuroscience, Utrecht University, Utrecht, The Netherlands; ¶ Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA DOI: 10.1111/j.1743-6109.2009.01660.x ABSTRACT Introduction. Measuring under naturally occurring circumstances increases ecological validity. We developed an ambulatory psychophysiological laboratory that allows experiments to be performed at home. Aims. To compare institutional laboratory task measures with ambulatory laboratory task measures. Main Outcome Measures. Vaginal pulse amplitude (VPA), clitoral blood volume (CBV), subjective report of sexual arousal, preconscious attentional bias for erotic stimuli, subjective reports about feeling at ease, tense, anxious or inhibited. Methods. VPA and CBV were measured in eight women with hypoactive sexual desire disorder (HSDD) and eight healthy controls while exposed to neutral and erotic film clips both in the institute’s laboratory and at home. Before and after film clip presentations, subjects performed an emotional Stroop task and completed two questionnaires. Results. In healthy controls, genital measures of sexual arousal were significantly increased at home compared with the institutional laboratory, whereas no differences were observed between the institutional laboratory and the at home measurements in women with HSDD. The responses at home were significantly higher in healthy controls compared with women with HSDD. Subjective experience of genital responding increased at home for both groups of women. Concordance between subjective experience and genital sexual arousal was more pronounced in the institutional laboratory setting. Preconscious attentional bias was stronger in the institutional laboratory for both groups of women. Healthy controls felt more at ease and less inhibited at home while subjects with HSDD did not. Conclusions. The use of an ambulatory laboratory is a valuable tool allowing psychophysiological (sex) research under more natural circumstances (e.g., a participant’s home). In this study, the increase in ecological validity resulted in a qualitative differentiation between the healthy controls and the women with HSDD in the home setting, which is not apparent in the artificial setting of the institutional laboratory. Bloemers J, Gerritsen J, Bults R, Koppeschaar H, Everaerd W, Olivier B, and Tuiten A. Induction of sexual arousal in women under conditions of institutional and ambulatory laboratory circumstances: A comparative study. J Sex Med 2010;7:1160–1176. Key Words. Ambulatory Laboratory; Ecological Validity; Hypoactive Sexual Desire Disorder; Clitoral Blood Volume; Inhibition; Genital Measures of Sexual Arousal Introduction I n sex research, it might be desirable to measure physiological and subjective sexual responses in the domestic environment of the participants. We introduce an ambulatory psychophysiological laboratory by which experiments can be per- formed under more naturally occurring circum- stances (e.g., at home without the presence of an experimenter). This ambulatory laboratory can be 1160 J Sex Med 2010;7:1160–1176 © 2010 International Society for Sexual Medicine