Eyetracking during picture naming predicts future vocabulary dropout in progressive anomia

ABSTRACT

The dynamic and unpredictable nature of expressive vocabulary dropout in progressive anomia presents a challenge for language intervention. We evaluated whether eye gaze patterns during naming could predict anomia for the same items in the near future. We tracked naming accuracy and gaze patterns as patients with semantic (n = 7) or logopenic (n = 2) variants of Primary Progressive Aphasia or amnestic Alzheimer’s Disease (n = 1), named photographs of people and objects. Patients were tested three or more times spaced roughly evenly over an average duration of 19.1 months. Target words named accurately at baseline were retrospectively coded as either known (i.e., consistently named) or vulnerable (i.e., inaccurately or inconsistently named) based on naming accuracy over the study interval. We extracted gaze data corresponding to successful naming attempts and implemented logistic mixed effects models to determine whether common gaze measures could predict each word’s naming status as known or vulnerable. More visual fixations and greater visual fixation dispersion predicted later anomia. These findings suggest that eye tracking may yield a biomarker of the robustness of particular target words to future expressive vocabulary dropout. We discuss the potential utility of this finding for optimizing treatment for progressive anomia.

KEYWORDS:

• Primary progressive Aphasia
• Naming
• Anomia
• Eyetracking
• Dementia

Acknowledgements

We thank the patients, their families, and the University of Pennsylvania FTD Center for supporting this research. We are also grateful to two anonymous reviewers for their care, encouragement, and dedication to helping us create something we are truly proud of.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Fixations are defined as periods of focused visual attention within a particular area of interest. The threshold of what constitutes a fixation vary across eyetracking systems. The eyetracker used here (SMI Red-M 120 Hz) delineates fixation as dwell time exceeding a duration of 80ms within a spatially disbursed area subtending no more than 2 degrees of visual angle (100 pixels).

2 Numerous case studies have highlighted altered higher level visual processing in PPA and AD, including changes in stylistic preferences for visual art (Baddeley et al., 2001; Green & Patterson, 2009; Miller & Miller, 2013; Perry & Hodges, 1999; Rizzo et al., 2000; Vernet et al., 2014; Viskontas et al., 2011).

Additional information

Funding

This work was funded by the US National Institute on Deafness and other Communication Disorders (NIDCD/NIH) [Grant Number: DC013063].