Doctor of Philosophy (PhD)


Department of Communication Sciences and Disorders

Document Type



The absence of culture- and language-specific aphasia assessment in Bangla underscores a critical problem in Communication Sciences and Disorders. Aphasia occurs in ~41% of stroke survivors. Over 40 years, stroke incidence has doubled in the low- and middle-income countries, such as Bangladesh and India, where there are ~250 million native Bangla speakers.

This study aimed to identify an appropriate picture stimulus for the Bangla Picture Description Task (PDT) intended for inclusion in a Bangla aphasia assessment. Researchers have reported the importance of cultural relevance and three visuographic variables of a picture, i.e., high-context, color, and photograph vs. black and white line drawing, for faster comprehension and comprehensive language production from people with aphasia and neurologically-healthy adults. The present study compared four culturally related and non-related picture stimuli with and without the three visuographic variables.

This study used a repeated-measures crossover design to analyze spontaneous language samples from neurologically-healthy native Bangla speakers in three age groups (young 19-30, middle 40-55, and old 65-89 years) to identify any age-related language production changes Bangla speakers experience.

Because a crossover design may generate carryover effects and thus influence a study’s findings, a linear mixed-effect (LME) model was used to identify the main effects in the presence of a possible carryover effect. Otherwise, a mixed multivariate analysis of variance (ANOVA) was used to determine the main effects. Moving-average type-token ratio (MATTR) was analyzed with mixed multivariate ANOVA. The LME model analyzed: 1) words per minute (WPM), 2) mean length of utterance in morphemes (MLU), and 3) total number of words. Finally, the complexity index (CI), a syntactic complexity measure, was analyzed with non-parametric tests because CI data was skewed. The study results demonstrated 1) a significant picture type effect for MATTR, WPM, and MLU, and 2) a significant age group effect for WPM, MLU, and CI.

After combining the findings of all measurement variables for three age groups, the present study reports the culturally related high-context color photograph is the appropriate stimulus for the Bangla PDT. This study also indicates that older adults 65 years and above experience reduced fluency, grammatical complexity, and syntactic complexity.



Committee Chair

Donovan, Neila J.



Available for download on Saturday, June 22, 2024