title: A Novel Pupillometric Method for Indexing   Word Difficulty in Individuals With   and Without Aphasia.
abstract: OBJECTIVE
  Cognitive effort is a clinically important facet of linguistic processing that is often overlooked in the assessment and treatment of people with aphasia (PWA). Furthermore, there is a paucity of valid ways to index cognitive effort in PWA. The construct of cognitive effort has been indexed for decades via pupillometry (measurement of pupil dilation and constriction during a cognitive task), yet pupillometry has not been implemented in studies including PWA. In the present study, we tested a novel method for indexing cognitive effort during linguistic processing in people with and without aphasia.
  
  
  METHODS
  Forty control participants and 39 PWA listened to semantically easy and difficult single nouns and looked at images while their pupillary responses were monitored. Mean pupil dilation in response to easy versus difficult nouns was calculated to index cognitive effort.
  
  
  RESULTS
  Larger mean pupil dilation values were obtained for difficult compared with easy nouns for both groups.
  
  
  CONCLUSIONS
  Results provide preliminary evidence that pupillometry can be used to index cognitive effort during linguistic processing of single nouns in people with and without aphasia. Methods for indexing cognitive effort will be a valuable addition to existing assessment methods. Suggestions for further research are offered.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Chapman
authors.forename: Brooke
authors.initials: B
authors.lastname: Hallowell
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001037:Aphasia / Q000503:physiopathology*; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology; D032882:Comprehension / Q000502:physiology; D004410:Dyslexia / Q000503:physiopathology; D005260:Female; D006801:Humans; D007802:Language; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012025:Reflex, Pupillary / Q000502:physiology*; D055815:Young Adult