Predicting confrontation naming item difficulty

ABSTRACT

Background: Item response theory (IRT; Lord & Novick, 1968) is a psychometric framework that can be used to model the likelihood that an individual will respond correctly to an item. Using archival data (Mirman et al., 2010), Fergadiotis, Kellough, and Hula (2015) estimated difficulty parameters for the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996) using the 1-parameter logistic IRT model. Although the use of IRT in test development is advantageous, its reliance on sample sizes exceeding 200 participants make it difficult to implement in aphasiology. Therefore, alternate means of estimating the item difficulty of confrontation naming test items warrant investigation. In a preliminary study aimed at automatic item calibration, Swiderski, Fergadiotis, and Hula (2016) regressed the difficulty parameters from the PNT on word length, age of acquisition (Kuperman, Stadthagen-Gonzalez, & Brysbaert, 2012), lexical frequency as quantified by the Log10CD index (Brysbaert & New, 2009), and naming latency (Székely et al., 2003). Although the model's predictive utility was high, a substantial proportion (20%) of the response time data were missing. Further, only 39% of the picture stimuli from Székely and colleagues (2003) were identical to those on the PNT. Given that the IRT sample size requirements limit traditional calibration approaches in aphasiology and that the initial attempts in predicting IRT difficulty parameters in our pilot study were based on incomplete response time data this study has two specific aims.

Aims: To estimate naming latencies for the 175 items on the PNT, and assess the utility of psycholinguistic variables and naming latencies for predicting item difficulty.

Methods and Procedures: Using a speeded picture naming task we estimated mean naming latencies for the 175 items of the PNT in 44 cognitively healthy adults. We then re-estimated the model reported by Swiderski et al (2016) with the new naming latency data.

Outcomes and Results: The predictor variables described above accounted for a substantial proportion of the variance in the item difficulty parameters (Adj. R² = .692).

Conclusions: In this study we demonstrated that word length, age of acquisition, lexical frequency, and naming latency from neurotypical young adults usefully predict picture naming item difficulty in people with aphasia. These variables are readily available or easily obtained and the regression model reported may be useful for estimating confrontation naming item difficulty without the need for collection of response data from large samples of people with aphasia.

KEYWORDS:

• Confrontation naming
• item response theory
• aphasia
• assessment
• psychometrics
• reaction time

Acknowledgments

The authors gratefully acknowledge the support of NIH/NIDCD (award # R03DC014556) to the first author and an ASHA SPARC Award to the second author, which supported presentation of preliminary results of this study to the 2016 Clinical Aphasiology Conference. The second author was affiliated with Portland State University when the data for this study were collected.

The authors also thank the Portland State University students who participated in the study and Lindsay Andreu and Erin Welp for their assistance with data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental material

Supplementary data for this articlepaper can be accessed here.

Additional information

Funding

This work was supported by the National Institute on Deafness and Other Communication Disorders [R03DC014556].