title: Rapid changes in arousal states of healthy volunteers during robot-assisted gait training: a quantitative time-series electroencephalography study.
abstract: BACKGROUND
  Robot-assisted gait training (RAGT) is expected to be an effective rehabilitative intervention for patients with gait disturbances. However, the monotonous gait pattern provided by robotic guidance tends to induce sleepiness, and the resultant decreased arousal during RAGT may negatively affect gait training progress. This study assessed electroencephalography (EEG)-based, objective sleepiness during RAGT and examined whether verbal or nonverbal warning sounds are effective stimuli for counteracting such sleepiness.
  
  
  METHODS
  Twelve healthy men walked on a treadmill for 6 min, while being guided by a Gait-Assistance Robot, under 3 experimental conditions: with sine-wave sound stimulation (SS), verbal sound stimulation (VS), and no sound stimulation (NS). The volunteers were provided with warning sound stimulation at 4 min (ST1), 4 min 20 s (ST2), 4 min 40 s (ST3), and 5 min (ST4) after the start of RAGT. EEGs were recorded at the central (Cz) and occipital (O1 and O2) regions (International 10-20 system) before and during RAGT, and 4-s segments of EEG data were extracted from the filtered data during the 8 experimental periods: middle of the eyes-closed condition; middle of the eyes-open condition; beginning of RAGT; immediately before ST1; immediately after ST1, ST2, ST3, and ST4. According to the method used in the Karolinska drowsiness test, the power densities of the theta, alpha 1, and alpha 2 bands were calculated as indices of objective sleepiness.
  
  
  RESULTS
  Comparisons of the findings between baseline and before ST showed that the power densities of the alpha 1 and 2 bands tended to increase, whereas the theta power density increased significantly (P < .05). During NS, the power densities remained at a constant high level until after ST4. During SS and VS, the power densities were attenuated immediately to the same degree and maintained at a constant low level until after ST4.
  
  
  CONCLUSIONS
  This study is the first to demonstrate that EEG-measured arousal levels decrease within a short time during RAGT, but are restored and maintained by intermittent warning sound stimulation.
authors.affiliation: Department of Rehabilitation Medicine, Faculty of Medicine, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan. yoshie-n@med.uoeh-u.ac.jp.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Futoshi
authors.initials: F
authors.lastname: Wada
authors.forename: Satoru
authors.initials: S
authors.lastname: Saeki
authors.forename: Kenji
authors.initials: K
authors.lastname: Hachisuka
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005081:Exercise Therapy / Q000009:adverse effects* / Q000379:methods*; D005684:Gait / Q000502:physiology; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D012371:Robotics / Q000379:methods; D013997:Time Factors
references.citation: Electroencephalogr Clin Neurophysiol. 1987 Jun;66(6):502-11
references.pmid: 2438115
references.citation: Psychophysiology. 1970 Mar;6(5):517-26
references.pmid: 5485539
references.citation: Clin Rehabil. 2004 Dec;18(8):833-62
references.pmid: 15609840
references.citation: Psychophysiology. 1984 Sep;21(5):510-20
references.pmid: 6473620
references.citation: Stroke. 2002 Dec;33(12):2895-901
references.pmid: 12468788
references.citation: Percept Mot Skills. 1998 Feb;86(1):147-61
references.pmid: 9530725
references.citation: Int J Neurosci. 1988 Feb;38(3-4):435-41
references.pmid: 3372157
references.citation: Ergonomics. 2010 Oct;53(10):1205-16
references.pmid: 20865604
references.citation: J Neuroeng Rehabil. 2012 Sep 07;9:65
references.pmid: 22953989
references.citation: Neurorehabil Neural Repair. 2007 Jul-Aug;21(4):307-14
references.pmid: 17476001
references.citation: Percept Mot Skills. 1967 Dec;25(3):697-703
references.pmid: 6081429
references.citation: Curr Protoc Neurosci. 2009 Oct;Chapter 10:Unit10.2
references.pmid: 19802813
references.citation: Cochrane Database Syst Rev. 2009 Jul 08;(3):CD006075
references.pmid: 19588381
references.citation: Stroke. 2008 Jun;39(6):1786-92
references.pmid: 18467648
references.citation: Electroencephalogr Clin Neurophysiol. 1981 May;51(5):483-95
references.pmid: 6165548
references.citation: Lancet. 1999 Jul 17;354(9174):191-6
references.pmid: 10421300
references.citation: Br J Sports Med. 1996 Sep;30(3):243-5
references.pmid: 8889120
references.citation: Accid Anal Prev. 2003 May;35(3):381-91
references.pmid: 12643955
references.citation: Cochrane Database Syst Rev. 2007 Oct 17;(4):CD006073
references.pmid: 17943883
references.citation: J Rehabil Res Dev. 2000 Nov-Dec;37(6):693-700
references.pmid: 11321005
references.citation: Cochrane Database Syst Rev. 2014 Jan 23;(1):CD002840
references.pmid: 24458944
references.citation: Cochrane Database Syst Rev. 2013 Jul 25;(7):CD006185
references.pmid: 23888479
references.citation: Thorax. 1984 Nov;39(11):818-22
references.pmid: 6505988
references.citation: J Sports Sci. 2002 Apr;20(4):345-52
references.pmid: 12003280
references.citation: J Clin Neurophysiol. 1987 Oct;4(4):327-82
references.pmid: 3316272
references.citation: J Sleep Res. 1995 Dec;4(S2):23-29
references.pmid: 10607207
references.citation: Neurorehabil Neural Repair. 2009 Jan;23(1):5-13
references.pmid: 19109447
references.citation: Cognition. 1999 Dec 17;73(3):B55-66
references.pmid: 10585521
references.citation: Biomed Tech (Berl). 1999 Jul-Aug;44(7-8):194-201
references.pmid: 10472726
references.citation: J Psychol. 1972 Nov;82(2d Half):339-46
references.pmid: 4655558
references.citation: Int J Neurosci. 1990 May;52(1-2):29-37
references.pmid: 2265922
references.citation: Percept Mot Skills. 1995 Jun;80(3 Pt 1):779-90
references.pmid: 7567395
references.citation: Sleep. 1979 Spring;1(3):281-6
references.pmid: 504873