Assessment of speech in neurological disorders: development of a Swahili screening test.
Assessments for acquired motor-speech disorders that look at movements of the articulators would appear at first glance to be universal. This may be true for the most basic non-speech aspects of movement. We argue that assessments for speech motor control must be attuned to language-specific variables to be fully valid. We describe the rationale for, and development of a motor-speech-disorder screening test for Swahili speakers which includes impairment measures as well as measures of intelligibility and speech-voice naturalness. We further describe its initial validation in terms of content validity, feasibility of administration and scoring without requirements for lengthy training and technical expertise and application to groups of people with and without Parkinson's disease in Tanzania. Results indicate that the protocol is ready to use in so far as it is acceptable to users (clinicians, patients), is feasible to use, shows good interrater reliability, and is capable of differentiating performance in healthy speakers and those whose speech is disordered. We highlight needs for further development, including issues around training, development of local norms for healthy speakers and for speakers with a variety of neurological disturbances, and extension of the tool to cover culturally valid assessment of impact of communication disorders.