Where (in the brain) do semantic errors come from?

BACKGROUND

Semantic errors result from the disruption of access either to semantics or to lexical representations. One way to determine the origins of these errors is to evaluate comprehension of words that elicit semantic errors in naming. We hypothesized that in acute stroke there are different brain regions where dysfunction results in semantic errors in both naming and comprehension versus those with semantic errors in oral naming alone.

METHODS

A consecutive series of 196 patients with acute left hemispheric stroke who met inclusion criteria were evaluated with oral naming and spoken word/picture verification tasks and magnetic resonance imaging within 48 h of stroke onset. We evaluated the relationship between tissue dysfunction in 10 pre-specified Brodmann's areas (BA) and the production of coordinate semantic errors resulting from (1) semantic deficits or (2) lexical access deficits.

RESULTS

Semantic errors arising from semantic deficits were most associated with tissue dysfunction/infarct of left BA 22. Semantic errors resulting from lexical access deficits were associated with hypoperfusion/infarct of left BA 37.

CONCLUSION

Our study shows that semantic errors arising from damage to distinct cognitive processes reflect dysfunction of different brain regions.