Aspects of spoken speech that are related to (1) how easily utterances are articulated (2) production of at least 50 words per minutes, and (3) utilization of sentence structure.
In contrast, only one out of eight aphasic subjects producing three or more perseverations had lesions restricted to the frontal lobe. In order to explain their findings, the authors entertained the idea that decreased verbal fluency associated with frontal lobe lesions results in decreased output that inhibits both the intended response and perseveration. However there were three exceptions: those aphasic patients with lesions restricted to the left frontal lobe did not perseverate, yet correctly named at least ten items.