Background Evaluating patients in the acute phase of brain damage allows for the early detection of cognitive and linguistic impairments and the implementation of more effective interventions. However, few cross-cultural instruments are available for the bedside assessment of language abilities. The aim of this study was to develop a brief assessment instrument and evaluate its content validity. Methods Stimuli for the new assessment instrument were selected from the M1-Alpha and MTL-BR batteries (Stage 1). Sixty-five images were redesigned and analyzed by non-expert judges (Stage 2). This was followed by the analysis of expert judges (Stage 3), where nine speech pathologists with doctoral training and experience in aphasiology and/or linguistics evaluated the images, words, nonwords, and phrases for inclusion in the instrument. Two pilot studies (Stage 4) were then conducted in order to identify any remaining errors in the instrument and scoring instructions. Results Sixty of the 65 figures examined by the judges achieved inter-rater agreement rates of at least 80%. Modifications were suggested to 22 images, which were therefore reanalyzed by the judges, who reached high levels of inter-rater agreement (AC1 = 0.98 [CI = 0.96–1]). New types of stimuli such as nonwords and irregular words were also inserted in the Brief Battery and favorably evaluated by the expert judges. Optional tasks were also developed for specific diagnostic situations. After the correction of errors detected in Stage 4, the final version of the instrument was obtained. Conclusion This study confirmed the content validity of the Brief MTL-BR Battery. The method used in this investigation was effective and can be used in future studies to develop brief instruments based on preexisting assessment batteries.

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