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Northwestern Assessment of Verb Inflection (NAVI)

NU 2017-036


Cynthia Thompson*

Jiyeon Lee


Short Description

The NAVI was designed to examine production of verb inflection forms in individuals with language disorders resulting from neurological disease. The NAVI is used to assess one’s ability to produce finite (present singular, present plural, past regular and irregular forms) and nonfinite (infinitive, present progressive) verb inflection forms in English, using a sentence completion task. The NAVI can be used in both research and clinical settings in order to test for the presence of verb inflection difficulties and the nature of such difficulties in adults with language disorders.


Purchase Options

Due to concerns surrounding COVID-19 and Northwestern University’s response, shipments of printed versions of NAVI will be delayed. Shipments will resume once Northwestern returns to standard operating procedures.

Thank you for your patience during this time.


The Northwestern Assessment of Verb Inflection (NAVI)

by Northwestern Aphasia Lab

  • Included:
    • (2) Picture stimulus books
    • (1) Examiner's manual
    • (1) Response Form
  • Price: $150.00



The Northwestern Assessment of Verb Inflection (NAVI) is available via a license from Northwestern University for research and clinical use.


Payment by credit card can be made after agreeing to the NAVI license agreement at checkout.  Your order will be shipped within ten (10) days of payment confirmed by your credit card.  Please allow 5-7 days for delivery.


What is NAVI?

Many individuals with neurogenic language disorders experience difficulty producing correct verb infection forms. In addition, different inflection forms can be affected differently. For example, an individual with aphasia may show greater difficulty with the past tense verb as in yesterday he danced, compared to the present progressive form as in now he is dancing. The NAVI was designed as a clinical and research tool to systematically examine the presence and nature of verb inflection difficulties in individuals with aphasia and related neurogenic language disorders.


The NAVI consists of 10 verbs, tested in five different verb inflection forms: two nonfinite forms (infinitive and present progressive) and three finite inflection forms (3rd person present singular, present plural, and past tense). Both regular and irregular verbs are tested, allowing comparison of production of regular (e.g., poured) and irregular (wrote) past tense forms. Inclusion of both the 3rd person present singular and plural forms allows assessment of the ability to produce inflectional marking for number agreement (e.g., the man eats vs. the men eat). The target verb inflection form is elicited using a sentence completion task (Now the man is _____ the hamburger). The NAVI also includes two supplementary tests, including the Phonological Screening Test and the Grammaticality Judgment Test of verb inflection to assist in better determining the nature of verb inflection deficits. Administration of the NAVI is relatively quick (approximately 15-30 minutes). The NAVI can be used as a stand-alone test for evaluating verb inflection morphology or as a supplementary assessment to complement more general language assessment tools such as the Northwestern Assessment of Verbs and Sentences (Thompson, 2011).



The NAVI is described in the following research papers:


1.    Lee, J., Mack, J., & Thompson, C. K. (2012). Verbal morphology in agrammatic and anomic aphasia: comparison of structured vs. narrative elicitation tasks. Poster presented at Clinical Aphasiology Conference, Lake Tahoe, CA.


2.    Lee, J., Wieneke, C., Weintraub, S., Mesulam, M-M., & Thompson, C. K. (2011). The Northwestern Assessment of Verb Inflections (NAVI): tense production in stroke-induced and primary progressive aphasia. Poster presented at The Annual American Speech & Hearing Association Convention, San Diego, CA.


3.    Thompson, C. K., Meltzer – Asscher, A., Cho, S., Lee, J., Wieneke, C., Weintraub, S., & Mesulam, M-M. (2013). Syntactic and morphosyntactic processing in stroke-induced and primary progressive aphasia. Behavioral Neurology, 25, 1-20.


4.    Wang, H., Yoshida, M., & Thompson, C.K. (2014). Parallel functional category deficits in clauses and nominal phrases: the case of English agrammatism. Journal of Neurolinguistics, 27(1), 75-102. PMCID:PMC4569143


5.    Lee, J., Yoshida, M., & Thompson, C. K. (2015). Grammatical planning units during real-time sentence production in agrammatic aphasia and healthy speakers. Journal of Speech, Language, and Hearing Sciences, 58, 1182-1194.


Refunds are available within 60 days of purchase under the following conditions:

• Materials must remain unused.

• Purchaser must contact Northwestern University at within 60 days from the date of purchase to initiate the refund request. Please provide a copy of the purchase receipt included with the request.

• 90% of the purchase price will be refunded.

• Purchaser must confirm destruction of the licensed materials upon request by Northwestern.

Refunds will not be issued for used materials or for requests made more than 60 days from the purchase date. Northwestern may refuse a refund request if evidence is found of fraud, refund abuse or other manipulative behavior that entitles Northwestern to a corresponding counterclaim.


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