title: The Main Concept Analysis: Validation and sensitivity in differentiating discourse produced by unimpaired English speakers from individuals with aphasia and dementia of Alzheimer type.
abstract: OBJECTIVE
  Discourse from speakers with dementia and aphasia is associated with comparable but not identical deficits, necessitating appropriate methods to differentiate them. The current study aims to validate the Main Concept Analysis (MCA) to be used for eliciting and quantifying discourse among native typical English speakers and to establish its norm, and investigate the validity and sensitivity of the MCA to compare discourse produced by individuals with fluent aphasia, non-fluent aphasia, or dementia of Alzheimer's type (DAT), and unimpaired elderly.
  
  
  METHODS
  Discourse elicited through a sequential picture description task was collected from 60 unimpaired participants to determine the MCA scoring criteria; 12 speakers with fluent aphasia, 12 with non-fluent aphasia, 13 with DAT, and 20 elderly participants from the healthy group were compared on the finalized MCA.
  
  
  RESULTS
  Results of MANOVA revealed significant univariate omnibus effects of speaker group as an independent variable on each main concept index. MCA profiles differed significantly between all participant groups except dementia versus fluent aphasia. Correlations between the MCA performances and the Western Aphasia Battery and Cognitive Linguistic Quick Test were found to be statistically significant among the clinical groups.
  
  
  CONCLUSIONS
  The MCA was appropriate to be used among native speakers of English. The results also provided further empirical evidence of discourse deficits in aphasia and dementia. Practitioners can use the MCA to evaluate discourse production systemically and objectively.
authors.affiliation: a Department of Communication Sciences and Disorders , University of Central Florida , Orlando , FL , USA.
authors.forename: Anthony Pak-Hin
authors.initials: AP
authors.lastname: Kong
authors.affiliation: a Department of Communication Sciences and Disorders , University of Central Florida , Orlando , FL , USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Whiteside
authors.affiliation: b Brain Fitness Club , Winter Park , FL , USA.
authors.forename: Peggy
authors.initials: P
authors.lastname: Bargmann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D000704:Analysis of Variance; D001037:Aphasia / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D016022:Case-Control Studies; D003071:Cognition; D032882:Comprehension; D003210:Concept Formation; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007802:Language; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index
keywords: Aphasia; assessment; dementia of the Alzheimer type; language; main concept analysis; oral discourse production