Aphasia and swallowing problems in subjects with incident stroke in rural northern Tanzania: a case-control study

This study was carried out to quantify the degree of cognitive impairment and the extent of speech, language, and swallowing problems in a representative cohort of Swahili-speaking people with stroke in Tanzania.

A case-control design was used, comparing people with and without stroke on a screening test for aphasia (spoken comprehension and expression), a water swallow test, and the Community Screening Instrument for Dementia (CSI-D).

Fifty-eight persons between 6 and 60 months (median 36) post stroke and 58 age- and gender-matched control subjects were assessed. Twenty-eight strokes were left hemisphere; 25, right; 2, posterior circulation; and 3, undetermined. Forty-nine of 58 (84%) control subjects scored 19 to 20 (maximum) on the language screen compared with 26 of 56 (46%) persons with stroke who completed the assessment. Higher age and lower educational attainment, but not gender or time since stroke, were associated with poorer performance on language and swallow assessments. Poorer CSI-D score was significantly correlated with all items. Greater disability (Barthel Index score) was significantly correlated with poorer performance in all items except rate of drinking water. Those with a left hemisphere stroke performed less well on understanding and expression items but better than other subjects with stroke on the water swallow task.

This is the first attempt to describe aphasia incidence in a sub-Saharan African language. Further work on the psychometric properties of the screening instrument is warranted. Given that it delivers a relatively coarse indication of language disturbance, it is likely that incidence of aphasia in the current cohort is underestimated.