Validation of the French sensory gating inventory: A confirmatory factor analysis
Introduction
Abnormal regulation and integration of sensory, perceptual and attentional processes and, in particular, sensory gating abnormalities are considered a core deficit among patients with schizophrenic disorder (Andreasen et al., 1994, Light and Braff, 2003, Micoulaud Franchi et al., 2013). In his early description of Dementia praecox, Bleuler (1911), p. 68 noted, “the selectivity which normal attention ordinarily exercises among the sensory impressions can be reduced to zero so that almost everything is recorded that reaches the senses. Thus, the facilitating as well as inhibiting properties of attention are equally disturbed” (cf. alsoLight and Braff, 2003, p. 47).
McGhie and Chapman (1961) confirmed Bleuler׳s (1911) results in patients with schizophrenia following a non-structured phenomenological interview. Through an analysis of verbatim accounts and an implementation of categorical structuring, the authors isolated two types of change in daily experience for patients with schizophrenia. The first change involved disturbances in the process of “perception”, including abnormalities in the quality of sensory input (i.e. perceived increases in stimulus intensity and a heightening of sensory vividness) with greater prevalence in auditory and visual modalities. Patients reported anomalies that they described as follows: “I have noticed that noises all seem to be louder” or “It is as if someone has turned up the volume”. The second type of change was disturbances in the process of “attention”, including distractibility and an inability to focus attention. Patients reported anomalies as follows: “The sounds are coming through to me, but I feel my mind cannot cope with everything. It is difficult to concentrate on any one sound” and “I listen to sounds all the time. I let all the sounds come in that are there” (McGhie and Chapman, 1961, p. 105).
Inspired by McGhie and Chapman׳s work (1961), two perceptual scales emerged to study sensory gating deficits in schizophrenia (Micoulaud-Franchi and Vion-Dury, 2013): the Structured Interview for Assessing Perceptual Anomalies (SIAPA) (Bunney et al., 1999) and the Sensory Gating Inventory (SGI) (Hetrick et al., 2012). The SIAPA is a structured interview administered to the patient that allows the interviewer to score the frequency of perceptual anomalies for the five sensory modalities on the three following dimensions: hypersensitivity, inundation/flooding, and selective attention to common external stimuli. Using this scale, Bunney et al. (1999) reported a significantly greater prevalence of auditory and visual perceptual anomalies in patients with schizophrenia compared to healthy subjects and, in doing so, confirmed the seminal results obtained by McGhie and Chapman. The SGI is a self-report questionnaire composed of 36 items addressing a broad range of sensory gating-like subjective experiences that are rated by the patients on a 6-point Likert scale. The psychometric properties of the SGI indicate that it provides valuable information on 4 dimensions of sensory gating-like experiences: Perceptual Modulation (PM) (linked to 16 items, e.g., “My hearing is so sensitive that ordinary sounds become uncomfortable”), Over-inclusion (OI) (7 items, e.g., “I notice background noises more than other people”), Distractibility (D) (8 items, e.g., “There are times when I cannot concentrate with even the slightest sounds going on”), and Fatigue-Stress Modulation (FS) (5 items, e.g., “It seems that sounds are more intense when I׳m stressed”)
The advantages of the SGI compared to SIAPA are: i) it is a self-report questionnaire that could more accurately assess patients׳ experiences than interviewer scoring (Slevin et al., 1988), ii) it uses items mainly based on verbatim accounts of face-to-face interviews (in particularly from McGhie and Chapman, 1961) that are known to be an effective way of constructing a questionnaire to assess self-experience (McKenna, 1997), iii) it has been subjected to factor analysis to demonstrate its construct validity (whereas the SIAPA was not), which is an important empirical psychometric property for validating a scale (Nunnally and Bernstein, 1994).
The perceptual scales investigating daily experiences of sensory gating deficit were developed for English speaking schizophrenia patients (Bunney et al., 1999, Chapman et al., 1978, Hetrick et al., 2012). In order to better examine French patients’ phenomenological sensory gating experiences (Micoulaud-Franchi and Vion-Dury, 2013), the purpose of this study was to design and validate a perceptual scale in French. Given the advantages of the SGI, we choose to adapt the SGI for use in French individuals. Translating questionnaires may be dependent on cultural background and, before using a translated questionnaire, it is necessary to perform a transcultural validation according to specific rules and methods. For the validation process, we analyzed the psychometric properties of the French SGI version. In particular, using confirmatory factor analysis (CFA), we determined whether this version behaves similarly to the original English version.
Section snippets
Participants
A group of 580 people: undergraduate students (230 subjects) and graduate teachers and engineer researchers (350 subjects), from four neuroscience labs and one acoustic lab of the Aix-Marseille University (AMU)1 were
Sample characteristics
A total of 363 participants completed the French version of the SGI. The mean age was 31.8 years old (S.D.=12.2, range: 18–63 years old); 75.5% were women. The percentage of responders to the web survey was 62%.
The mean PAS score was 4.5 (S.D.=4.8) and the mean TAI score was 37.2 (S.D.=10.6), which fall within the range of scores that have previously been demonstrated in the literature for healthy subjects (Dumas et al., 2000, Spielberger, 1983).
Construct validity and internal structural validity
Results are presented in Table 1, Table 2.
The 4
Discussion
The aim of this study was to translate and validate the French version of the SGI, aiming at measuring the daily experience of sensory gating deficit in patients with schizophrenia. The transcultural validation supports the structural validity of the adapted instrument for the French population.
The psychometric properties were satisfactory; the domains described in Hetrick et al. (2012) were considered appropriate for investigating sensory gating experience of French participants. The CFA was
Conflict of interest
The authors report no conflicts of interest.
Acknowledgments
This work was supported by CNRS (Centre National de la Recherche Scientifique) with credit of UMR 7291. The "Unité de Neurophysiologie et Psychophysiologie" is a member of Reseau FondaMental. Also thanks to Marie Gueye for her help in the statistical analysis.
References (30)
- et al.
Is P50 suppression a measure of sensory gating in schizophrenia?
Biological Psychiatry
(1998) - et al.
Sensory gating deficits in schizophrenia: can we parse the effects of medication, nicotine use, and changes in clinical status
Clinical Neuroscience Research
(2003) - et al.
Do self-reports of perceptual anomalies reflect gating deficits in schizophrenia patients?
Biological Psychiatry
(2000) - et al.
What is sensory inundation in schizophrenia?
Clinical Neurophysiology
(2013) - et al.
Thalamic abnormalities in schizophrenia visualized through magnetic resonance image averaging
Science
(1994) - et al.
The robustness of LISREL modeling revisited
- et al.
Uniform indices of fit for factor analysis models
Multivariate Behavioral Research
(1988) - et al.
Structured Interview for Assessing Perceptual Anomalies (SIAPA)
Schizophrenia Bulletin
(1999) - et al.
Sensory gating deficits assessed by the P50 event-related potential in subjects with schizotypal personality disorder
American Journal of Psychiatry
(2000)