Primary progressive aphasia (PPA) affects a range of language and cognitive domains that impact on conversation. Little is known about conversation breakdown in the semantic variant of PPA (svPPA, also known as semantic dementia). This study investigates conversation of people with svPPA.

Dyadic conversations about everyday activities between seven individuals with svPPA and their partners, and seven control pairs were video recorded and transcribed. Number of words, turns, and length of turns were measured. Trouble-indicating behaviors (TIBs) and repair behaviors were categorized and identified as successful or not for each participant in each dyad.

In general, individuals with svPPA were active participants in conversation, taking an equal proportion of turns, but indicating a great deal of more trouble in conversation, shown by the significantly higher number of TIBs than evidenced by partners or control participants. TIBs were interactive (asking for confirmation with a shorter repetition of the original utterance or a repetition which included a request for specific information) and non-interactive (such as failing to take up or continue the topic or a minimal response) and unlike those previously reported for people with other PPA variants and dementia of the Alzheimer type. Communication behaviors of the partner were critical to conversational success.

Examination of trouble and repair in 10-min conversations of individuals with svPPA and their important communication partners has potential to inform speech pathology interventions to enhance successful conversation, in svPPA and should be an integral part of the comprehensive care plan.