Phonemic Fluency Tasks Research Articles

The Hippocampal Contribution to Verbal Fluency in Patients with Temporal Lobe Epilepsy

We report the effects of hippocampal and non-hippocampal temporal-lobe dysfunction on verbal fluency performance. Quantitative aspects of semantic and phonemic fluency performance were examined in 46 patients with right- or left-temporal-lobe epilepsy and 20 healthy controls. A pattern of fewer words generated on semantic rather than phonemic fluency tasks was found among patients with damage to hippocampal structures. This pattern was not obtained in patients with non-hippocampal temporal-lobe damage, suggesting that the hippocampus plays a crucial role in semantic fluency performance. An interesting lateralization effect was obtained. Among patients with left temporal-lobe involvement, fluency performance was impaired regardless of whether the hippocampus was involved. In contrast, among patients with right temporal-lobe involvement, fluency performance was impaired only when the hippocampus was involved.

Developmental Aspects of Verbal Fluency and Confrontation Naming in Children

Developmental changes in children's verbal fluency and confrontation naming were explored in this study. One hundred and sixty children (ages 5 years and 11 months to 11 years and 4 months) completed two verbal fluency tasks (phonemic and semantic) and the Boston Naming Test (BNT). Normative data were compiled for the BNT and the phonemic and semantic fluency tasks. With the exception of the phonemic fluency task, all tests showed a linear increase from year-groups I to V, with a significant increase between year-groups I and II. Principal Component Factor Analysis was conducted to determine whether the tests evaluated similar or different functions. Two factors emerged: the first involving all of the measurements and the second explaining exclusively the phonemic fluency. These results make it possible to conclude that children also seem to have different subsystems responsible for the analysis and processing of different aspects of language.

Absence of Hemispheric Dominance for Mental Rotation Ability: A Transcranial Doppler Study

Mean blood flow velocity (MFV) of the middle cerebral arteries was monitored in 19 healthy, adult, right-handed subjects during the resting phase and the execution of a series of neuropsychological tests: two right/left discrimination tasks, two mental rotation paradigms (the Ratcliff's test and a cube comparison test) and a phonemic fluency task, which was utilised as an internal control. In the group as a whole, the Ratcliff's test was associated with a significant bilateral increase in MFV versus both the resting state (right: p < .000001, left: p < .000001) and right/left discrimination tasks (task 1: right: p = .003, left: p = .005; task 2: right: p = .001, left: p = .001). The cube comparison in turn produced a significant increase in MFV versus both the baseline conditions (right: p < .000001, left: p < .000001) and the Ratcliff's test (right: p = .01, left: p = .002). As expected, the fluency task was associated with a significant asymmetric increase in cerebral perfusion (left > right: p = .0001). Increasing task difficulty (right/left discrimination < Ratcliff's test < cube comparison) was paralleled by a roughly proportional rise in MFV values (right: r = .424, p < .01; left: r = .331, p = .01). In conclusion, we were able to demonstrate that (1) in addition to the amount of MFV variation due to right/left discrimination (when required), mental rotation per se causes a biemispheric activation irrespective of the experimental paradigm; (2) the MFV variation is proportional to the difficulty of the tasks.

Phonemic and semantic fluencies in traumatic brain injury patients with focal frontal lesions

The purpose of this study was to investigate the effect of focal frontal lesions, identified by magnetic resonance imaging (MRI), in a group of traumatic brain injured (TBI) patients, in order to clarify the sensitivity of phonemic and semantic fluency tasks as tests of frontal lobe functioning. Thirteen TBI patients were included and matched with a normal control group of 26 subjects. Frontal lobe patients produced significantly fewer words than the control group in the phonemic fluency condition. Semantic performance correlated with lesion size, but phonemic performance did not, corroborating the idea that the two have different brain-based substrates. Although, as a group effect, frontal lesions impaired fluency, not all patients were impaired, even in the presence of large bilateral frontal lesions.

Comparative Analysis of Qualitative Verbal Fluency Performance in Normal Elderly and Demented Populations

Verbal fluency tasks are commonly used in the assessment of patients with known or suspected dementia. Whereas total word production is often analyzed, less attention has been paid to qualitative aspects of verbal fluency performance. The purpose of this study was to examine the diagnostic utility of a qualitative scoring technique for semantic and phonemic fluency tasks in individuals with Alzheimer's disease (AD), Parkinson's disease (PD) with and without dementia, and in a group of older normal controls (ONC). In addition to total words produced, the groups were compared on their use of clustering (i.e., ratio of words generated within subcategories) and switching (i.e., frequency of shifts between clusters) strategies as originally defined by Troyer et al. (1997a). In terms of total number of words produced, controls were superior to the AD and demented PD subjects, who performed similarly. A similar trend was found in relation to switching and clustering scores. PD patients without dementia performed similar to the ONC group on semantic fluency, but were impaired relative to controls on all phonemic fluency variables (i.e., total words produced, clustering, switching). Discriminant function analyses using the three fluency variables revealed that total words was equal to or surpassed the other variables in distinguishing the groups, suggesting that these qualitative verbal fluency features may not provide significant additional information in terms of diagnostic utility.

A Comparison of Phonemic, Semantic, and Alternating Word Fluency in Parkinson's Disease

Word fluency in 45 medicated non-demented Parkinson's disease (PD) patients and 45 normal control subjects was studied with a Phonemic Word Fluency (PWF) task using the letters F, A, and S, a Semantic Word Fluency (SWF) task using the categories animals, boys' names, and states, and an Alternating Word Fluency (AWF) task requiring the person to alternate between colors and occupations, animals and states, and words beginning with C and P. The number of words generated did not differ for trials with F, A, S, or states, but PD patients generated significantly fewer animal names and boys' names. PD patients also generated significantly fewer words on each of the three AWF trials. The PD patients scored 21% lower than the normal control group on the total AWF score, but only 10% lower for the PWF and SWF scores. The greater impairment on the AWF task which requires the use of internal attentional control to rapidly shift mental set can be considered a type of executive functioning deficit. This is consistent with the growing literature suggesting frontal systems dysfunction in PD and with the view that dopaminergic treatment only incompletely restores functioning in the frontostriatal system.

A Comparison of Phonemic, Semantic, and Alternating Word Fluency in Parkinson’s Disease

Word fluency in 45 medicated non-demented Parkinson’s disease (PD) patients and 45 normal control subjects was studied with a Phonemic Word Fluency (PWF) task using the letters F, A, and S, a Semantic Word Fluency (SWF) task using the categories animals, boys’ names, and states, and an Alternating Word Fluency (AWF) task requiring the person to alternate between colors and occupations, animals and states, and words beginning with C and P. The number of words generated did not differ for trials with F, A, S, or states, but PD patients generated significantly fewer animal names and boys’ names. PD patients also generated significantly fewer words on each of the three AWF trials. The PD patients scored 21% lower than the normal control group on the total AWF score, but only 10% lower for the PWF and SWF scores. The greater impairment on the AWF task which requires the use of internal attentional control to rapidly shift mental set can be considered a type of executive functioning deficit. This is consistent with the growing literature suggesting frontal systems dysfunction in PD and with the view that dopaminergic treatment only incompletely restores functioning in the frontostriatal system.

Pupillary Responses Evoked during Verbal Fluency Tasks Indicate Semantic Network Dysfunction in Schizophrenia

Pupillary responses, which index task controlled processing load, were recorded during semantic and phonemic fluency tasks to examine controlled search and automatic semantic network deficits in patients with schizophrenia. Word retrieval was more impaired on semantic than on phonemic fluency, but only during the first 15 seconds of trials. Pupillary dilation was greater on phonemic than on semantic fluency in nonpsychiatric participants but was greater on semantic than on phonemic fluency in the patients, during the first 15 seconds of trials. Thus, early in semantic fluency trials, patients with schizophrenia showed poorer word retrieval and abnormally high demand for frontal lobe controlled search processes, suggesting impairments in the temporal lobe automatic semantic memory processes that normally facilitate word retrieval.

Comparison of phonemic and semantic verbal fluency tasks: an fMRI study

Comparison of phonemic and semantic verbal fluency tasks: an fMRI study

Test-retest reliability of the national adult reading test (NART) as an estimate of premorbid IQ in patients with schizophrenia

A growing body of evidence have suggested that non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can improve the performance of aphasic patients in language tasks. For example, application of inhibitory rTMS or tDCs over the right frontal lobe of dysphasic patients resulted in improved naming abilities. Several studies have also reported that in healthy controls (HC) tDCS application over the left prefrontal cortex (PFC) improve performance in naming and semantic fluency tasks. The aim of this study was to investigate in HC, for the first time, the effects of inhibitory repetitive TMS (rTMS) over left and right lateral frontal cortex (BA 47) on two phonemic fluency tasks (FAS or FPL). 44 right-handed HCs were administered rTMS or sham over the left or right lateral frontal cortex in two separate testing sessions, with a 24 h interval, followed by the two phonemic fluency tasks. To account for possible practice effects, an additional 22 HCs were tested on only the phonemic fluency task across two sessions with no stimulation. We found that rTMS-inhibition over the left lateral frontal cortex significantly worsened phonemic fluency performance when compared to sham. In contrast, rTMS-inhibition over the right lateral frontal cortex significantly improved phonemic fluency performance when compared to sham. These results were not accounted for practice effects. We speculated that rTMS over the right lateral frontal cortex may induce plastic neural changes to the left lateral frontal cortex by suppressing interhemispheric inhibitory interactions. This resulted in an increased excitability (disinhibition) of the contralateral unstimulated left lateral frontal cortex, consequently enhancing phonemic fluency performance. Conversely, application of rTMS over the left lateral frontal cortex may induce a temporary, virtual lesion, with effects similar to those reported in left frontal patients.

Influences of clustering and switching on the verbal fluency performance of patients with alzheimer's disease

Several lines of evidence suggest that in Alzheimer's disease (AD) there is a progressive degradation of the hierarchical organization of semantic memory. to evaluate this hypothesis, clustering and switching on phonemic and semantic fluency tasks were studied. For elderly controls, both clustering and switching were correlated with the numbers of correct words generated on both fluency tests, but the contribution of clustering was greater on the semantic task. Patients with AD generated fewer correct words and made fewer switches than controls on both fluency tests. the average size of their semantic clusters was smaller and the contribution of clustering to word generation was less than for controls. Severity of dementia was correlated with the numbers of correct words and switches, but not with cluster size. These results are consistent with various hypotheses which maintain that the structure of semantic memory in AD is degraded but provide no evidence that this process is progressive. Instead, progressive worsening of verbal fluency in AD seems to be more strongly associated with the deterioration of mechanisms that govern initiation of search for appropriate subcategories.

Word-list generation deficits in dementia.

To evaluate the specificity of the semantic fluency deficit in Alzheimer's disease (AD), we compared the performances of patients with AD, Huntington's disease (HD), vascular dementia (VD), and healthy control subjects on tasks of category (i.e., semantic) and first-letter (i.e., phonemic/lexical) word list generation. As compared to age-appropriate controls, all three patient groups demonstrated relatively more impaired semantic than phonemic fluency. Dementia severity did not affect this relationship. Thus, the greater vulnerability of semantically guided fluency is not specific to AD but occurs in other dementias as well. Deficits in both the organization of semantic memory and retrieval from long-term storage appear to contribute to the relatively poorer performance on semantic than phonemic fluency tasks observed in patients with AD, VD, and HD.