Bifactor Confirmatory Factor Analysis Research Articles

Kidney Disease Quality of Life 36-Item Short Form Survey (KDQOL-36) Normative Values for the United States Dialysis Population and New Single Summary Score.

The Kidney Disease Quality of Life 36-item short form survey (KDQOL-36) is a widely used, patient-reported outcome measure for patients on dialysis. Efforts to aid interpretation are needed. We used a sample of 58,851 dialysis patients participating in the Medical Education Institute (MEI) KDQOL Complete program, and 443,947 patients from the US Renal Data System (USRDS) to develop the KDQOL-36 Summary Score (KSS) for the kidney-targeted KDQOL-36 scales (Burdens of Kidney Disease [BKD], Symptoms and Problems of Kidney Disease [SPKD], and Effects of Kidney Disease [EKD]). We also used the MEI and USRDS data to calculate normative values for the Short Form-12 Health Survey's Physical Component Summary (PCS) and Mental Component Summary (MCS), and the KDQOL-36's BKD, SPKD, and EKD scales for the United States dialysis population. We used confirmatory factor analysis (CFA) models for KDQOL-36 kidney-targeted items, evaluated model fit with the comparative fit index (CFI; >0.95 indicates good fit) and root-mean-squared error of approximation (RMSEA; <0.06 indicates good fit), and estimated norms by matching the joint distribution of patient characteristics in the MEI sample to those of the USRDS sample. A bifactor CFA model fit the data well (RMSEA=0.046, CFI=0.990), supporting the KSS (α=0.91). Mean dialysis normative scores were PCS=37.8 and MCS=50.9 (scored on a T-score metric); and KSS=73.0, BKD=52.8, SPKD=79.0, and EKD=74.1 (0-100 possible scores). The KSS is a reliable summary of the KDQOL-36. The United States KDQOL-36 normative facilitate interpretation and incorporation of patient-related outcome measures into kidney disease care.

Nonrestorative sleep scale: reliable and valid for the Chinese population.

To conduct a linguistic and psychometric evaluation of a Chinese version of the Nonrestorative Sleep Scale (NRSS). The Chinese NRSS was created from a standard forward-backward translation and trialed on 10 Chinese adults. Telephone interviews were then conducted with 100 adults, who completed the Chinese NRSS, the Pittsburgh Sleep Quality Index (PSQI), the Athens Insomnia Scale (AIS), the Center for Epidemiological Studies Depression Scale (CES-D), and the Toronto Hospital Alertness Test (THAT). A household survey was conducted with 20 subjects, followed by a confirmatory factor analysis (CFA), and a bifactor model was developed to evaluate the reliability and validity of the NRSS. The bifactor model had the root mean square error of approximation (RMSEA), standardized root mean square residual (SRMR), and comparative fit index (CFI) of 0.06, 0.06, and 0.97, respectively. Convergent validity was shown from the moderate associations with PSQI (r = - 0.66, P < 0.01), AIS (r = - 0.65, P < 0.01), CES-D (r = - 0.54, P < 0.01), and THAT (r = 0.68, P < 0.01). The coefficient omega (0.92), omega hierarchical (0.81), factor determinacy (0.93), H value (0.91), explained common variance (0.63), and percentage ofuncontaminated correlations (0.80) derived from the bifactor CFA supported the essential unidimensionality of NRSS. The Chinese NRSS is a valid and reliable essential unidimensional tool for the assessment of nonrestorative sleep in the Chinese population.

Psychometric Properties and Structures of the IAT, GPIUS and GAS Scales: A Bifactor Approach

This study applied a bifactor approach to investigate the structures and simultaneously compare the psychometric properties of three popular self-report internet addiction (IA) instruments. A bifactor confirmatory factor analysis was used to address the structures of the three scales, while the bifactor multidimensional item response model was employed to compare the psychometric properties of the three scales. Results of bifactor confirmatory factor analysis (CFA) showed that the bifactor structures were suitable for the three scales. These corresponding bifactor structures were used in the subsequent bifactor multidimensional item response theory (MIRT) analysis. Results of the bifactor MIRT showed that: three instruments of IA performed well as a whole; the Generalised Problematic Internet Use Scale (GPIUS) and Internet Addiction Test (IAT) provided more test information and had less standard error of measurement, which ranged from −3 to −1 standard deviations of theta or IA severity; the Game Addiction Scale (GAS) performed better than the other two scales in that it can provide more test information in the large area of IA severity (from −1 to +3 SDs). These suggest that the GPIUS and IAT may be the best choice for epidemiological IA studies and for measuring those with lower IA severity. Meanwhile, the GAS may be a good choice when we recruit those with various levels of IA severity.

Early Childhood Acceptance Rejection Questionnaire: Psychometric Properties of the Greek Version

Present study examined the ECPARQ with four different higher order techniques (Bifactor EFA, Bifactor CFA, Bifactor ESEM, Second-order CFA) plus a simple CFA (ICM CFA), evaluating a total of 19 models. All models were tested twice, one for the ECPARQ Mother version and one for the Father version. For each version, alternative models were tested with 2, 3 and 4-factor structures. All models were tested having item 13 both in the intended factor and alternatively in the Warmth factor. This comparison was made to empirically answer in what factor the item 13 belongs. All higher order models had an adequate fit, suggesting thus the theoretical construct of the Warmth dimension of Parenting is supported for the Greek cultural context, although further investigation is necessary. ICM-CFA had equally adequate fit, thus preferable based on parsimony. All models tested having item 13 in the Warmth factor had superior fit in comparison to their counterparts with item 13 in the Indifference/Neglect factor. Internal consistency reliability was adequate.

A Composite Measure of Caregiver Burden in Dementia: The Dementia Burden Scale-Caregiver.

To better capture the scope of caregiver burden by creating a composite of 3 existing measures that assess different health domains. Prospective follow-up study. University-based dementia care management program. Caregivers of persons with dementia (PWD) (N=1,091). The composite measure (the Dementia Burden Scale-Caregiver (DBS-CG)) was based on the Modified Caregiver Strain Index, Neuropsychiatric Inventory Questionnaire Distress Scale, and Patient Health Questionnaire (PHQ-9). Alternative factor structures were evaluated using 2 confirmatory factor analysis (CFA) models: a bifactor model and a 3 correlated factors model. Good model fit was defined as a root mean square error of approximation (RMSEA) of less than 0.06 and comparative fit index (CFI) value greater than 0.95. Coefficient omega was used to estimate scale reliability. Minimally important differences (MIDs) were estimated by anchoring the magnitude of DBS-CG change to change in caregiver self-efficacy and functional ability of PWD. The bifactor CFA model fit best (RMSEA = 0.04, CFI = 0.95). Based on this model, a DBS-CG scale was created wherein all items were transformed to a possible range of 0 to 100 and then averaged. Higher scores indicate higher burden. Mean DBS-CG score was 27.3. The reliability was excellent (coefficient omega=0.93). MID estimates ranged from 4 to 5 points (effect sizes: 0.20-0.49). This study provides support for the reliability and validity of the DBS-CG. It can be used as an outcome measure to assess the effect of interventions to reduce dementia caregiver burden.

Psychometric properties of the Cognitive and Metacognitive Learning Strategies Scales among preservice physical education teachers: A bifactor analysis

Although widely used to measure self-regulated learning strategies, the Motivated Strategies for Learning Questionnaire has not yielded satisfactory construct validity across empirical studies. This study examined its psychometric properties by focusing on one of its subscales, the Cognitive and Metacognitive Learning Strategies Scales, among 419 preservice physical education teachers ( M age = 23.05 years, SD = 4.28) from five physical education teacher preparation programmes in the southwestern United States of America. The participants responded to the 31-item Cognitive and Metacognitive Learning Strategies Scales, which assessed five categories of learning strategies: rehearsal, elaboration, organization, critical thinking, and metacognitive self-regulation. Each item was on a seven-point Likert scale. Initial confirmatory factor analysis did not support the original five-factor model. Following exploratory factor analysis identified three latent factors. Subsequent bifactor exploratory factor analysis revealed one general factor and two group factors, and following bifactor confirmatory factor analysis confirmed that this structure had an acceptable model fit, χ2 (353) = 731.327, p &lt;.001; Root Mean Square Error of Approximation = .053; Comparative Fit Index = .907; Standardized Root Mean Square Residual = .047. A respecified bifactor model with 18 items resulted in a good fit, χ2 (120) = 161.384, p &lt;.001; Root Mean Square Error of Approximation = .030; Comparative Fit Index = .980; Standardized Root Mean Square Residual = .034. Score reliability for the general factor Omega Hierarchical = .825; for the two group factors, Omega Scales = .211 and .238, respectively. Implications for future research and practice are discussed.

Using Bifactor EFA, Bifactor CFA and Exploratory Structural Equation Modeling to Validate Factor Structure of the Meaning in Life Questionnaire, Greek Version

The purpose of this study was to evaluate the structure, invariance, reliability, convergent and discriminant validity of the MLQ with exploratory and confirmatory factor analysis in 1561 Greek adults. After sample-splitting, a two-factor EFA and a two-factor bifactor EFA model were tested in the first sample. Then, seven CFA models were tested (three ICM-CFA models, two bifactor CFA models and two ESEM models) in the second sample. Two-factor ESEM representation was notably better than the ICM-CFA models and marginally better than the bifactor model. Optimal ESEM model was successfully cross-validated in a third sample. MLQ was also proved to be invariant across gender. Internal consistency reliability was adequate. Convergent and discriminant validity were also examined. Considering all findings, MLQ is gender invariant, reliable and valid to use in Greek cultural context.

A 3-Faced Construct Validation and a Bifactor Subjective Well-Being Model Using the Scale of Positive and Negative Experience, Greek Version

The present study focused on the dimensionality of the Scale of Positive and Negative Experience (SPANE) by: 1) providing evidence that the Greek version of SPANE is a robust affect measure; 2) constructing a new, briefer SPANE version, the SPANE-8 with promising psychometric profile. The construct validation was implemented on 2272 Greek adults using the “3-faced construct validation method”, a construct validation procedure based on sample-splitting. Sample was split in three parts. EFA and Bifactor EFA models were evaluated in the 20% subsample. Then, in the 40% subsample, a total of 10 CFA models were examined (ICM-CFA, Bifactor CFA, ESEM and Bifactor ESEM models). The optimal models of SPANE-12 and SPANE-8 were successfully cross-validated in another 40% subsample. Strict measurement invariance, using the optimal model as a baseline model was successful for both SPANE versions. Reliability (α and ω) and AVE convergent validity were also satisfactory. Correlation analysis based on 10 different measures showed a consistent scheme of relations for both versions. Finally, a Bifactor CFA subjective well-being model using SPANE to measure affect was adequately fitted. In sum, the Greek version of SPANE-12 and the new SPANE-8 are invariant, reliable and valid measures of affect. Normative data are made available.

Can the Depression Anxiety Stress Scales Short Be Shorter? Factor Structure and Measurement Invariance of DASS-21 and DASS-9 in a Greek, Non-Clinical Sample

This study focused on the factor structure, invariance, reliability, and validity of two DASS versions: DASS-21 and DASS-9. Dimensionality was examined with Exploratory and Confirmatory factor analysis in 2271 Greek adults of the non-clinical population. Sample was split in three parts and the “3-faced construct validation method” was adopted. An EFA and a Bifactor EFA model were tested in the 20% subsample for both DASS-21 and DASS-9. Then, in the 40% subsample eleven CFA models were tested for DASS-21 and six for DASS-9 (using ICM-CFA, Bifactor CFA and ESEM). Optimal DASS-21 and DASS-9 models were successfully validated in the remaining 40% subsample (i.e. in a subsample of equal power). DASS-21 and DASS-9 showed strict measurement invariance across gender. Reliability (α and ω) and AVE convergent validity were adequate for both versions. Correlation analysis based on 10 different measures revealed a predominant uniform pattern of relations, similar for both versions. Considering all findings, the Greek versions of DASS-21 and DASS-9 are invariant, reliable and show construct and convergent validity.

The Flow Short Scale (FSS) Dimensionality and What MIMIC Shows on Heterogeneity and Invariance

The purpose of this research was to examine the psychometric properties of the Flow Short Scale by Rheinberg, Vollmeyer, and Engeser in 160 Greek adults. State flow (as opposed to dispositional flow) was measured while participants were involved in a leisure time activity. First, construct validity was evaluated with factor analysis techniques like ICM-CFA, ESEM, Bifactor CFA and Bifactor ESEM. A total of 15 alternative models were evaluated. Two solutions showed optimal fit. First, it was the two-factor structure replicating the original structure but with different item allocation on each factor, probably due to cultural differences. Second, it was a shorter version of FSS with 6 items in the two original factors instead of 10. A MIMIC model indicated a significant direct effect of age on FSS factors thus, population heterogeneity. A significant direct effect on an indicator was also found, hence measurement noninvariance. Reliability (α and ω) was acceptable, but not AVE. Flow had a significant positive, moderately strong relation with emotionality and life satisfaction. In sum, the suggested factor structures for FSS were found to be reliable and valid to use in Greek cultural context.

Applied Psychometrics: The 3-Faced Construct Validation Method, a Routine for Evaluating a Factor Structure

The “3-faced construct validation method” is a routine for establishing the validity and reliability of an existing scale when adapted in a different cultural context from the context initially developed. This routine can also be used for the initial validation of a newly developed scale. This is essentially a construct validation procedure based on a sample-splitting. The sample is randomly split into three parts, 20% for EFA, 40% for an exploratory CFA and 40% for a cross-validating CFA. The cases per variable threshold is set above 5:1, preferably above 10:1 (minimum conditions) and the first approximately 20% subsample emerges (adequate conditions) to evaluate EFA and Bifactor EFA models. Then the cases per variable threshold is set above 10:1, preferably above 20:1 (minimum conditions) and the 40% subsample emerges (adequate conditions) to examine alternative CFA models (ICM-CFA, Bifactor CFA, ESEM and Bifactor ESEM models). The optimal model(s) is cross-validated by a second CFA in yet another 40% subsample (equal-power CFA sample) as a protection against overfitting (over-optimization) to safeguard model replicability. Measurement invariance follows and is essentially another cross-check of the optimal model over the entire sample because the optimal model is used as the baseline model.

A Reexamination of Child Problem Behaviors as Measured by ECBI: Factor Structure and Measurement Invariance Across Two Parent Training Interventions.

The Eyberg Child Behavior Inventory (ECBI) is a widely used instrument that assesses disruptive problem behaviors via parent report. The present study compares three different conceptualizations of problem behaviors using traditional confirmatory factor analysis (CFA), a bifactor-CFA, and a bifactor exploratory structural equation model, whereof the latter two represent novel conceptualizations of disruptive problem behaviors. Data were derived from 353 Norwegian parents assigned to parent management training-the Oregon model (PMTO; N = 137) or brief parent training (BPT; N = 216), who rated their child's problem behavior (age 3-12 years). The factor models were estimated within the PMTO and BPT samples, and in the total sample. Results showed that the bifactor-CFA, with a general problem behavior factor and three specific factors representing oppositional defiant, conduct problem, and inattentive behavior provided the best model fit. Furthermore, factorial invariance across control/intervention groups and across time (pre/post intervention) was estimated within the PMTO and BPT samples. Results revealed properties of metric and intercept invariance across intervention/control groups and over time, within both interventions. Implications of the results are discussed.

Validity and Reliability of the Positive Aspects of Caregiving (PAC) Scale and Development of Its Shorter Version (S-PAC) Among Family Caregivers of Older Adults.

To (a) assess the validity and reliability of the 9-item Positive Aspects of Caregiving (PAC) scale among a national sample of caregivers for older adults with functional limitations, (b) develop a shorter version (short-PAC [S-PAC] scale) and assess its psychometric properties, and (c) investigate both scales' measurement equivalence/invariance (ME/I) across language of administration (Chinese/English/Malay). Scale/item measurement property assessment, confirmatory factor analysis (CFA), testing the "original" 2-factor model (6 items: first factor; 3 items: second factor), and exploratory FA (EFA) of the 9-item PAC scale was done. Consequently, alternate CFA models were tested. The S-PAC was developed and subjected to CFA. For both scales, convergent (correlation with caregiver esteem) and divergent (correlation with caregiver depressive symptoms) validity, and language ME/I was assessed. For the 9-item PAC scale, the "original" 2-factor CFA model had a poor fit; its EFA and scale/item measurement properties supported a single factor. Among alternate CFA models, a bi-factor model (all nine items: first factor [overall PAC]; six items: second factor [self-affirmation]; three items: third factor [outlook-on-life]) had the best fit. The bi-factor CFA model also had a good fit for the S-PAC scale, developed after eliminating 2 items from the 9-item PAC scale. Both scales demonstrated convergent and divergent validity, and partial ME/I across language of administration. Both the 9-item PAC and 7-item S-PAC scales can be used to assess positive feelings resulting from care provision among family caregivers of older adults with functional limitations.

Structural validity of the Machiavellian Personality Scale: A bifactor exploratory structural equation modeling approach

The Machiavellian Personality Scale (MPS; Dahling, Whitaker, & Levy, 2009) was designed to measure four content subdomains (i.e., amorality, desire for control, desire for status, and distrust of others). In this study, we evaluated the structural validity of MPS by testing a series of six competing models, including the one-factor CFA model, the four-factor CFA model, the higher-order CFA model, the exploratory structural equation modeling (ESEM) model, the bifactor CFA model, and the bifactor exploratory structural equation modeling (B-ESEM) model. The findings suggested that the B-ESEM model, which took two sources of psychometric multidimensionality into account, provided the best fit to the data. Although the Machiavellian Personality Scale was dominated by the global Machiavellianism, the measurement quality of the subdomains varied, with the desire for control sub-factor being more clearly defined than the other three specific factors (i.e., amorality, desire for status, and distrust of others). Recommendations were made about the use of the Machiavellianism Personality Scale in practice. Ethical statementAll the subjects gave written informed consent, and the protocol was approved by the research ethics review board of Xinyang Normal University. The authors have declared that no competing interests exist.

Development and Validation of the Body Concealment Scale for Scleroderma.

Body concealment is a component of social avoidance among people with visible differences from disfiguring conditions, including systemic sclerosis (SSc). The study objective was to develop a measure of body concealment related to avoidance behaviors in SSc. Initial items for the Body Concealment Scale for Scleroderma (BCSS) were selected using item analysis in a development sample of 93 American SSc patients. The factor structure of the BCSS was evaluated in 742 Canadian patients with single-factor, 2-factor, and bifactor confirmatory factor analysis models. Convergent and divergent validity were assessed by comparing the BCSS total score with the Brief-Satisfaction with Appearance Scale (Brief-SWAP) and measures of depressive symptoms and pain. A 2-factor model (Comparative Fit Index [CFI] 0.99, Tucker-Lewis Index [TLI] 0.98, Root Mean Square Error of Approximation [RMSEA] 0.08) fit substantially better than a 1-factor model (CFI 0.95, TLI 0.94, RMSEA 0.15) for the 9-item BCSS, but the Concealment with Clothing and Concealment of Hands factors were highly correlated (α = 0.79). The bifactor model (CFI 0.99, TLI 0.99, RMSEA 0.08) also fit well. In the bifactor model, the omega coefficient was high for the general factor (ω = 0.80), but low for the Concealment with Clothing (ω = 0.01) and Concealment of Hands (ω = 0.33) factors. The BCSS total score correlated more strongly with the Brief-SWAP Social Discomfort (r = 0.59) and Dissatisfaction with Appearance (r = 0.53) subscales than with measures of depressive symptoms and pain. The BCSS sum score is a valid indicator of body concealment in SSc that extends the concepts of body concealment and avoidance beyond the realms of body shape and weight to concerns of individuals with visible differences from SSc.

An Evaluation of Items and Dimensional Structure of a Scale to Measure Teachers’ Professional Commitment in Thailand

The purpose of this study was to examine the items and the dimensionality of a scale to measure professional commitment of teachers in Thailand. Data were collected by in-depth interview and questionnaire. The content analysis was conducted with the qualitative data for the purpose of item writing. Differential item functioning (DIF), exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and bi-factor CFA model analysis were conducted to establish validity evidence. As a result of EFA and CFA, the study showed that a 3-dimensional scale can effectively measure professional commitment of teachers, which was achieved by the 18-item measure. A polytomuos item response theory model was also fitted to estimate item parameters and to examine the test information function.

Validity and model-based reliability of the Work Organisation Assessment Questionnaire among nurses

BackgroundThe Work Organisation Assessment Questionnaire (WOAQ) was developed as part of a risk assessment tool for the manufacturing setting (Griffiths, Cox, Karanika, Khan, Tomás, 2006). The WOAQ was used in this study to assess its validity and model-based reliability among Australian nurses using a conventional second-order and a bifactor confirmatory factor analysis (CFA). MethodsThis article reports a study of Australian participants (N = 312) to validate a multidimensional measure of the WOAQ. Data were collected from a group of Australian community nurses. CFA was performed comparing a conventional second-order model and a bifactor model of one WOAQ summative factor and its five subfactors, which together described the most common issues of work design and management in organizations. A group of close fit indices that include relatively greater penalties for model complexity (i.e., the root mean square error of approximation, Non-normed Fit Index, and the Akaike Information Criterion) were chosen to interpret the results. ResultsThe results of reliability and validity analysis revealed some evidence for the summative measure of the WOAQ. Results indicate that the questionnaire is a valid and reliable scale, but some subfactors are more plausible than others within the Australian nursing community. ConclusionThe study provides future researchers some guidance for bifactor modeling in organizational studies of this type. The WOAQ provides flexibility to measure risk assessment and management procedures.

Incremental validity of WISC-IV(UK) factor index scores with a referred Irish sample: predicting performance on the WIAT-II(UK.).

Subtest and factor scores have typically provided little incremental predictive validity beyond the omnibus IQ score. This study examined the incremental validity of Wechsler Intelligence Scale for Children - Fourth UK Edition (WISC-IV(UK) ; Wechsler, 2004a, Wechsler Intelligence Scale for Children - Fourth UK Edition, Harcourt Assessment, London, UK) and factor index scores in predicting academic achievement on the Wechsler Individual Achievement Test - Second UK Edition (WIAT-II(UK) ; Wechsler, 2005a, Wechsler Individual Achievement Test-Second UK Edition, Pearson, London, UK), beyond that predicted by the WISC-IV(UK) FSIQ. The sample included 1,014 Irish children (ages 6-0 to 16-9) who were referred for evaluation of learning difficulties. Hierarchical multiple regression analyses were used with the WISC-IV(UK) FSIQ (Block 1) and factor index scores (Block 2) as predictors and WIAT-II(UK) subtest and composite scores as dependent variables. The WISC-IV(UK) FSIQ accounted for statistically significant and generally large portions of WIAT-II(UK) subtest and composite score variance. WISC-IV(UK) factor index scores combined to provide statistically significant increments in prediction of most WIAT-II(UK) subtest and composite scores over and above the FSIQ; however, the effect sizes were mostly small as previously observed (i.e., Canivez, 2013a, Psychol. Assess., 25, 484; Glutting et al., 2006, J. Spec. Educ., 40, 103; Nelson et al., 2013, Psychol. Assess., 25, 618). Individually, the WISC-IV(UK) factor index scores provided small unique contributions to predicting WIAT-II(UK) scores. This, in combination with studies of apportioned variance from bifactor confirmatory factor analysis (Watkins et al., 2013, Int. J. Sch. Educ. Psychol., 1, 102), indicated that the WISC-IV(UK) FSIQ should retain the greatest weight in WISC-IV(UK) interpretation.

Bifactor structure of clinical disability in relapsing multiple sclerosis

BackgroundMultiple sclerosis (MS) can affect virtually every neurological function which complicates the conceptualization and assessment of disability. Similar challenges are encountered in other medical fields including child cognitive development and psychiatry, for instance. In these disciplines progress in diagnosis and outcome measurement has been recently achieved by capitalizing on the concept of bifactor model. ObjectiveTo present in accessible terms an application of bifactor confirmatory factor analysis to study the clinical disability outcomes in MS. MethodsData included 480 assessments on 301 patients with relapsing–remitting MS who participated in the North American interferon beta-1a clinical trial (Avonex). Measures consisted of the Expanded Disability Status Scale (EDSS), the three components of the Multiple Sclerosis Functional Composite (MSFC), and five other clinical measures of neurological functions. We determined which of three confirmatory factor analysis models (unidimensional, multidimensional, and bifactor) best described the structure of the data. ResultsEDSS scores ranged from 0 to 8 (94% between 0 and 4). The final bifactor model fitted the data well, explained 59.4% of total variance, and provided the most useful representation of the data. In this model, the nine measures defined a scoring dimension of global neurological function (63.1% of total composite score variance) and two auxiliary dimensions of extra variability in leg and cognitive function (17.1% and 9% of total composite score variance). ConclusionBifactor modeling is a promising approach to further understanding of the structure of disability in MS and for refining composite measures of global disability.

Neuroanatomical correlates of behavioural phenotypes in behavioural variant of frontotemporal dementia

BackgroundBehavioural variant of frontotemporal dementia (bvFTD) frequently presents complex behavioural changes, that rarely occur in isolation. Targeting behavioural phenotypes instead of single behavioural symptoms may potentially provide a disease model in which to investigate brain substrates of behavioural abnormalities. ObjectiveTo identify behavioural phenotypes and to assess the associated brain correlates in a cohort of patients with bvFTD. MethodsTwo hundred and seven consecutive individuals fulfilling clinical criteria for bvFTD were enrolled. Each participant's caregiver completed frontal behavioural inventory on 24 key behavioural disturbances. Confirmatory factor analysis (CFA) models were applied, and behavioural phenotypes identified. For each phenotype, a score was derived based on the “best” CFA model (Bifactor CFA). One hundred two participants underwent SPECT scan. A regression analysis between scores for each factor and regional cerebral blood flow was carried out (P<0.001). ResultsOne “general” behavioural phenotype and four factors were identified, that were termed “disinhibited”, “apathetic”, “aggressive”, and “language” phenotypes. The most robust brain correlate was identified for “disinhibited” phenotype, in the region of the anterior cingulated and anterior temporal cortex, bilaterally, and for apathetic phenotype in the left dorsolateral frontal cortex. As expected, language phenotype correlated with greater hypoperfusion in the left frontotemporal lobes. No significant correlation between aggressive phenotype and regional cerebral blood flow was found. Moreover, the “general” behavioural severity was associated with greater damage in the right frontal lobe. ConclusionsBehavioural phenotypes are associated with specific brain damage in bvFTD, involving distinct cerebral networks.