Objective: Word comprehension deficits in neurodegenerative conditions are most striking in the syndrome of semantic dementia. Tests of word comprehension typically examine concrete and abstract nonemotion words. Whether or not understanding of words describing emotion concepts (e.g., insulted, fascinated) is also impaired in the dementias has not been systematically investigated.
Method: Patients with semantic dementia (SD; n = 8), behavioral-variant frontotemporal dementia (bvFTD; n = 8), Alzheimer's disease (AD; n = 12), as well as healthy controls (n = 15) completed newly designed emotion word comprehension tasks. Participants also undertook the Graded Synonyms Test, an abstract and concrete nonemotion word comprehension measure.
Results: Degradation of knowledge about negative and positive emotion words was most impaired in SD. Correlation analyses in the SD group also showed that knowledge of emotion words correlated with the understanding of abstract nonemotion words. The bvFTD group was impaired only when making associations for emotion words. The AD cohort did not differ from controls on any measures of word comprehension.
Conclusions: Impairment in word knowledge is greatest in the syndrome of SD, compared with bvFTD and AD, and includes concrete words, abstract words as well as emotion words. Importantly, word comprehension deficits affect positive and negative emotions.