The differing roles of the frontal cortex in fluency tests

Abstract

Fluency tasks have been widely used to tap the voluntary generation of responses. The anatomical correlates of fluency tasks and their sensitivity and specificity have been hotly debated. However, investigation of the cognitive processes involved in voluntary generation of responses and whether generation is supported by a common, general process (e.g. fluid intelligence) or specific cognitive processes underpinned by particular frontal regions has rarely been addressed. This study investigates a range of verbal and non-verbal fluency tasks in patients with unselected focal frontal (n=47) and posterior (n=20) lesions. Patients and controls (n=35) matched for education, age and sex were administered fluency tasks including word (phonemic/semantic), design, gesture and ideational fluency as well as background cognitive tests. Lesions were analysed by standard anterior/posterior and left/right frontal subdivisions as well as a finer-grained frontal localization method. Thus, patients with right and left lateral lesions were compared to patients with superior medial lesions. The results show that all eight fluency tasks are sensitive to frontal lobe damage although only the phonemic word and design fluency tasks were specific to the frontal region. Superior medial patients were the only group to be impaired on all eight fluency tasks, relative to controls, consistent with an energization deficit. The most marked fluency deficits for lateral patients were along material specific lines (i.e. left-phonemic and right-design). Phonemic word fluency that requires greater selection was most severely impaired following left inferior frontal damage. Overall, our results support the notion that frontal functions comprise a set of specialized cognitive processes, supported by distinct frontal regions.

Recovering and Worsening at Design Fluency in 22 Neurosurgical Patients: Preimmediately Post-surgery and Follow-up Testing

“…For a meta-analysis of studies comparing neuropsychological test scores pre-and postsurgery [7]. This is also in line with previous studies showing a deficit in design fluency after surgery [5,6,20]). Interestingly, different sub-groups of patients emerged at T1.…”

“…It is known that a deficit in design fluency can emerge in neurosurgical patients as an effect of lesion, thus detected prior to surgery [2], or can arise post-surgery [4][5][6], as an effect of tumor resection. In a recent meta-analysis [7] the need of more studies with longer post-op cognitive follow-up testing to better understand the conclusive effects of glioma surgery on cognition has been highlighted.…”

Phonemic and semantic verbal fluency tasks: normative data for elderly Brazilians

“…Robinson, Shallice, Bozzali and Cipolotti (2012) investigated how the frontal cortex behaves in different fl uency tasks (verbal, drawings, gestures, for example) with neurological patients (tumor and stroke). In verbal fl uency tasks observed that both types of verbal fl uency activates the frontal lobe, although the phonemic task was more specifi c in differentiating patients with frontal lesions of posterior lesions.…”

Functional connectivity in resting state as a phonemic fluency ability measure

“…In the case of phonemic fluency, the area most involved was the left inferior frontal gyrus (LIFG), a brain area implicated in word production and speech processing on different tasks, especially phonemic fluency (Broca, 1861;Bookheimer, 2002;Demonet, Fiez, Paulesu, Petersen, & Zatorre, 1996;Hirshorn & Thompson-Schill, 2006;Indefrey & Levelt, n.d.;Price, 2000Price, , 2010. Neuropsychological studies have revealed that patients with lesions in the left frontal lobe were more impaired in phonemic fluency than those with right frontal lesions (Robinson, Shallice, Bozzali, & Cipolotti, 2012). Although right inferior frontal activation has been related with semantic tasks (sentence comprehension) (Price, 2010), it is also relevant because has been associated with attentional switching and response inhibition (Hampshire, Chamberlain, Monti, Duncan, & Owen, 2010).…”