Verb and noun deficits in stroke-induced and primary progressive aphasia: The Northwestern Naming Battery

Abstract

Background: Word class naming deficits are commonly seen in aphasia resulting from stroke (StrAph) and primary progressive aphasia (PPA), with differential production of nouns (objects) and verbs (actions) found based on StrAph type or PPA variant for some individuals. However, studies to date have not compared word class naming (or comprehension) ability in the two aphasic disorders. In addition there are no available measures for testing word class deficits, which control for important psycholinguistic variables across language domains. This study examined noun and verb production and comprehension in individuals with StrAph and PPA using a new test, the Northwestern Naming Battery (NNB; Thompson & Weintraub, experimental version), developed explicitly for this purpose. In addition we tested verb type effects, based on verb argument structure characteristics, which also is addressed by the NNB.

Method: A total of 52 participants with StrAph (33 agrammatic, Broca's (StrAg); 19 anomic (StrAn)) and 28 PPA(10 agrammatic (PPA-G); 14 logopenic (PPA-L); 4 semantic (PPA-S)) were included in the study. Nouns and verbs were tested in the Confrontation Naming and Auditory Comprehension subtests of the NNB, with scores used to compute noun to verb ratios as well as performance by verb type. Performance patterns within and across StrAph and PPA groups were then examined. The external validity of the NNB was also tested by comparing (a) NNB Noun Naming scores to the Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 2001) and Western Aphasia Battery (WAB-R; Kertesz, 2007) Noun Naming subtest scores, (b) NNB Verb Naming scores to the Boston Diagnostic Aphasia Examination (BDAE; Goodglass, Kaplan, & Barresi, 2001) Action Naming score (for StrAph participants only), and (c) NNB Comprehension subtest scores to WAB-R Auditory Comprehension subtest scores.

Outcomes & Results: Both agrammatic (StrAg and PPA-G) groups showed significantly greater difficulty producing verbs compared to nouns, but no comprehension impairment for either word class, whereas three of the four PPA-S participants showed poorer noun compared to verb production, as well as comprehension. However, neither the StrAn nor the PPA-L participants showed significant differences between the two word classes in production or comprehension. In addition, similar to the agrammatic participants, the StrAn participants showed a significant transitivity effect, producing intransitive (one-argument) verbs with greater accuracy than transitive (two- and three-argument) verbs. However, no transitivity effects were found for the PPA-L or PPA-S participants. There were significant correlations between NNB scores and all external validation measures.

Conclusions: These data indicate that the NNB is sensitive to word class deficits in stroke and neurodegenerative aphasia. This is important both clinically for treatment planning and theoretically to inform both psycholinguistic and neural models of language processing.

Keywords:

• Primary progressive aphasia
• PPA
• Word class deficits
• Naming deficit patterns
• Verb argument structure production

Acknowledgments

The authors wish to thank the National Institutes of Health DC01948 (C. K. Thompson), DC008552 (M-M. Mesulam), and AG13854 (Alzheimer's Disease Core Center, Northwestern University) for support for this study. We also thank Gulustu Kaptanoglu MD and Swathi Kiran PhD for their assistance with development of the Northwestern Naming Battery, and Lisa Bailey PhD, Sarah Banks PhD, Kyla Garabladi BS, Jennifer Medina PhD, Lisa Milman PhD, Miseon Lee PhD, Janet O'Connor MS, and Emily Rogalski PhD for their assistance with data collection and analysis during various phases of test validation and development.

Notes

¹ Tauopathies are a class of neurodegenerative diseases associated with the pathological aggregation of tau protein in the human brain.

² WAB AQs for StrAn-5 and Str-An-14 exceeded the “cut-off” score for aphasia (i.e., 93.8) as did a subset of “recovered” aphasic individuals (n = 21) described by Kertesz (2007), who demonstrated word-finding difficulty or paraphasic errors, justifying a clinical diagnosis of aphasia. However, because of their high scores, these participants were not included in the WAB standardisation sample.

³ PPA-L6 and PPA-L12 evinced WAB AQ scores of 97.2 and 97.1, respectively, exceeding the “cut-off” for aphasia. The WAB, however, was standardised on individuals with aphasia resulting from stroke, not PPA. Notably, PPA participants often present with mild impairments, at least in initial stages. In addition these PPA patients were part of a large-scale longitudinal study and were retested on follow-up visits occurring after completion of the present study. PPA-L12 evinced scores on follow-up visits 2 and 3 of 90.3 and 81.3, respectively (within the AQ range of aphasia for StrAp); PPA-L6 scored 94.3 on visit 2 (this patient has not yet undergone visit 3 testing, however, we anticipate further language decline for this patient as well). Also see footnote 2 above.

⁴ In a separate analysis we used age as a covariate and found similar results: a significant main effect for group, F(2, 77) = 11.01, p < .001, with control participants outperforming both StrAph (p = .000) and PPA (p = .011) participants.

⁵ The F value was adjusted for lack of sphericity using Greenhouse-Geisser constant.

⁶ TDP-43 proteinopathy referes to the neuropathology underlying major forms of sporadic and familial frontotemporal lobar degeneration and motor neurone disease.