title: Analysis of vestibular-balance symptoms according to symptom duration: dimensionality of the Vertigo Symptom Scale-short form.
abstract: BACKGROUND
  Dizziness or vertigo is associated with both vestibular-balance and psychological factors. A common assessment tool is the Vertigo Symptom Scale (VSS) -short form, which has two subscales: vestibular-balance and autonomic-anxiety. Despite frequent use, the factor structure of the VSS-short form has yet to be confirmed. Here, we clarified the factor structure of the VSS-short form, and assessed the validity and reliability of the Japanese version of this tool.
  
  
  METHODS
  We conducted a cross-sectional, multicenter, psychometric evaluation of patients with non-central dizziness or vertigo persisting for longer than 1 month. Participants completed the VSS-short form, the Dizziness Handicap Inventory, and the Hospital Anxiety and Depression Scale. They also completed the VSS-short form a second time 1-3 days later. The questionnaire was translated into Japanese and cross-culturally adapted. We conducted a confirmatory factor analysis followed by an exploratory factor analysis. Convergent and discriminant validity, internal consistency, and test-retest reliability were evaluated.
  
  
  RESULTS
  The total sample and retest sample consisted of 159 and 79 participants, respectively. Model-fitting for a two-subscale structure in a confirmatory factor analysis was poor. An exploratory factor analysis produced a three-factor structure: long-duration vestibular-balance symptoms, short-duration vestibular-balance symptoms, and autonomic-anxiety symptoms. Regarding convergent and discriminant validity, all hypotheses were clearly supported. We obtained high Cronbach's α coefficients for the total score and subscales, ranging from 0.758 to 0.866. Total score and subscale interclass correlation coefficients for test-retest reliability were acceptable, ranging from 0.867 to 0.897.
  
  
  CONCLUSIONS
  The VSS-short form has a three-factor structure that was cross-culturally well-matched with previous data from the VSS-long version. Thus, it was suggested that vestibular-balance symptoms can be analyzed separately according to symptom duration, which may reflect pathophysiological factors. The VSS-short form can be used to evaluate vestibular-balance symptoms and autonomic-anxiety symptoms, as well as the duration of vestibular-balance symptoms. Further research using the VSS-short form should be required in other languages and populations.
authors.affiliation: Department of Psychiatry and Cognitive-Behavioral Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan. kondo-masaki@umin.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kondo
authors.affiliation: Department of Psychiatry, Yoshida Hospital, Nobeoka, Miyazaki, Japan. kensuke_kiyomizu@med.miyazaki-u.ac.jp.|Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan. kensuke_kiyomizu@med.miyazaki-u.ac.jp.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kiyomizu
authors.affiliation: Department of Otorhinolaryngology, National Hospital Organization, Tokyo Medical Center, Meguro, Tokyo, Japan. amifumi@bc5.so-net.ne.jp.
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Goto
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. tkitahara@naramed-u.ac.jp.|Department of Otorhinolaryngology-Head and Neck Surgery, Nara Medical University, Kashihara, Nara, Japan. tkitahara@naramed-u.ac.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. imaitakao@hotmail.com.
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.affiliation: Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. makoto@yamaguchi-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hashimoto
authors.affiliation: Department of Otolaryngology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. shimo-h@yamaguchi-u.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimogori
authors.affiliation: Department of Otolaryngology, Saitama Medical University, Iruma, Saitama, Japan. ikez@saitama-med.ac.jp.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ikezono
authors.affiliation: Department of Otolaryngology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan. nakayama@med.nagoya-cu.ac.jp.
authors.forename: Meiho
authors.initials: M
authors.lastname: Nakayama
authors.affiliation: Department of Clinical Epidemiology, Translational Medical Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. noriow@ncnp.go.jp.
authors.forename: Norio
authors.initials: N
authors.lastname: Watanabe
authors.affiliation: Department of Psychiatry and Cognitive-Behavioral Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan. takechi@med.nagoya-cu.ac.jp.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Akechi
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004244:Dizziness / Q000175:diagnosis* / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D014717:Vertigo / Q000175:diagnosis* / Q000523:psychology