title: Impaired prepulse inhibition and habituation of acoustic startle response in Japanese patients with schizophrenia.
abstract: Prepulse inhibition (PPI) and habituation of the acoustic startle reflex (ASR) are considered to be candidate endophenotypes of schizophrenia. However, to our knowledge, only one group has investigated these startle measures in Asian patients with schizophrenia. In the present study, we evaluated these startle measures in 51 Japanese patients with schizophrenia and compared them with those of 55 healthy age- and sex-matched Japanese controls. A human startle response monitoring system was used to deliver acoustic startle stimuli, and record and score the electromyographic activity of the orbicularis oculi muscle. The startle measures examined were mean magnitude of ASR to pulse alone trials in initial block (SR), habituation of ASR during the session (HAB), and PPI at prepulse intensities of 82 dB (PPI82), 86 dB (PPI86), and 90 dB (PPI90) sound pressure level. SR was not significantly different between the patients and controls. Patients displayed significantly reduced HAB and PPI for all prepulse intensities compared to controls. The greatest statistical difference in PPI between patients and controls was found with PPI86. This did not correlate with any clinical variable in each group. Our results indicate that PPI and habituation of ASR are impaired in Asian patients with schizophrenia.
authors.affiliation: Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. hidetaka@psy.med.osaka-u.ac.jp
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Masao
authors.initials: M
authors.lastname: Iwase
authors.forename: Ryouhei
authors.initials: R
authors.lastname: Ishii
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Ohi
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Fukumoto
authors.forename: Michiyo
authors.initials: M
authors.lastname: Azechi
authors.forename: Koji
authors.initials: K
authors.lastname: Ikezawa
authors.forename: Ryu
authors.initials: R
authors.lastname: Kurimoto
authors.forename: Leonides
authors.initials: L
authors.lastname: Canuet
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakahachi
authors.forename: Naomi
authors.initials: N
authors.lastname: Iike
authors.forename: Shinji
authors.initials: S
authors.lastname: Tagami
authors.forename: Takashi
authors.initials: T
authors.lastname: Morihara
authors.forename: Masayasu
authors.initials: M
authors.lastname: Okochi
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Tanaka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kazui
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tanimukai
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yasuda
authors.forename: Takashi
authors.initials: T
authors.lastname: Kudo
authors.forename: Ryota
authors.initials: R
authors.lastname: Hashimoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Takeda
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001767:Blinking / Q000187:drug effects; D003627:Data Interpretation, Statistical; D004576:Electromyography; D005260:Female; D006185:Habituation, Psychophysiologic / Q000187:drug effects*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D013216:Reflex, Startle / Q000187:drug effects*; D012565:Schizophrenic Psychology; D055815:Young Adult