Comparing the difficulty of letter, semantic, and name fluency tasks for normal elderly and patients with Parkinson's disease

Corpus callosum and cerebellum participate in semantic dysfunction of Parkinson's disease: a diffusion tensor imaging-based cross-sectional study

Language dysfunction is common in Parkinson's disease (PD) patients, among which, the decline of semantic fluency is usually observed. This study aims to explore the relationship between white matter (WM) alterations and semantic fluency changes in PD patients. 127 PD patients from the Parkinson's Progression Markers Initiative cohort who received diffusion tensor imaging scanning, clinical assessment and semantic fluency test (SFT) were included. Tract-based special statistics, automated fiber quantification, graph-theoretical and network-based analyses were performed to analyze the correlation between WM structural changes, brain network features and semantic fluency in PD patients. Fractional anisotropy of corpus callosum, anterior thalamic radiation, inferior front-occipital fasciculus, and uncinate fasciculus, were positively correlated with SFT scores, while a negative correlation was identified between radial diffusion of the corpus callosum, inferior longitudinal fasciculus, and SFT scores. Automatic fiber quantification identified similar alterations with more details in these WM tracts. Brain network analysis positively correlated SFT scores with nodal efficiency of cerebellar lobule VIII, and nodal local efficiency of cerebellar lobule X. WM integrity and myelin integrity in the corpus callosum and several other language-related WM tracts may influence the semantic function in PD patients. Damage to the cerebellum lobule VIII and lobule X may also be involved in semantic dysfunction in PD patients.

Differential contribution of language and executive functioning to verbal fluency performance in glioma patients

Glioma patients often suffer from deficits in language and executive functioning. Performance in verbal fluency (generating words within one minute according to a semantic category-category fluency, or given letter-letter fluency) is typically impaired in this patient group. While both language and executive functioning play a role in verbal fluency, the relative contribution of both domains remains unclear. We aim to retrospectively investigate glioma patients' performance on verbal and nonverbal fluency and to explore the influence of language and executive functioning on verbal fluency. Sixty-nine adults with gliomas in eloquent areas underwent a neuropsychological test battery (verbal fluency, nonverbal fluency, language, and executive functioning tests) before surgery (T1) and a subgroup of 31 patients also at three (T2) and twelve months (T3) after surgery. Preoperatively, patients were impaired in all verbal fluency tasks and dissociations were found based on tumour location. In contrast, nonverbal fluency was intact. Different language and executive functioning tests predicted performance on category fluency animals and letter fluency, while no significant predictors for category fluency professions were found. The longitudinal results indicated that category fluency professions deteriorated after surgery (T1-T2, T1-T3) and that nonverbal fluency improved after surgery (T1-T3, T2-T3). Verbal fluency performance can provide information on different possible underlying deficits in language and executive functioning in glioma patients, depending on verbal fluency task selection. Efficient task (order) selection can be based on complexity. Category fluency professions can be selected to detect more permanent long-term deficits.

Analyses of correct responses and errors on measures of verbal fluency among Parkinson's disease and essential tremor patients

Objective: Parkinson's disease (PD) and essential tremor (ET) involve neuroanatomical circuitry that impact frontal lobe functioning, via the striatum and cerebellum, respectively. The aim of this exploratory study was to investigate quantitative and qualitative performance between and within these groups on measures of verbal fluency. Method: Sixty-three PD and 53 ET patients completed neuropsychological testing. Linear regression models with robust variance estimation compared verbal fluency performance between groups related to correct responses and errors. Paired t-tests investigated within group error rates. Results: PD patients gave more correct responses for phonological (β ̂   =5.3, p=.01) and category fluency (β ̂   =4.1, p=.01) than ET patients; however, when processing speed was added as a covariate, this attenuated performance on both measures and only phonological fluency remained significant (β ̂   =4.0, p=.04). There were no statistical differences in error scores between groups. Error rates within groups suggested that PD patients had higher error rates in total errors and perseveration errors on phonological fluency (M = 2.6, p=.00; M = 1.6, p=.00) and higher total errors and set-loss error rates on category switching (M = 5.1, p<.001; M = 4.1, p<.001). ET patients had higher error rate with relation to total errors and set-loss errors on phonological fluency (M = 2.5, p=.00; M = 1.5, p=.02) and category switching (M = 3.9, p=,00; M = 3.9, p<.001). Conclusions: PD patients performed better than ET patients on phonological fluency. PD patients appear to make more perseveration errors on phonological fluency, while ET patients made more set-loss errors. Implications for frontal lobe dysfunction and clinical impact are discussed.

How well does the discrepancy between semantic and letter verbal fluency performance distinguish Alzheimer's dementia from typical aging?

In Alzheimer's dementia (AD), greater declines in semantic fluency (SF) relative to letter fluency (LF) have been assumed to reflect semantic disintegration. However, the same pattern is observed in typical aging and neurodegenerative disorders besides AD. We examined this assumption by comparing different aspects of SF and LF performance in older adults with and without dementia, and identifying which verbal fluency measures most clearly distinguish AD from typical aging. Verbal fluency data were compared from 109 individuals with AD and 66 typically aging adults. Correct items, clusters, and errors were analyzed using both raw counts and proportions. Regression analyses examined Task-by-Group interactions and the impact of demographic variables on verbal fluency measures. ROC analyses examined the sensitivity and specificity of the different outcome measures. In regressions, interactions were found for raw but not proportional data, indicating that different group patterns were driven largely by the number of correct items produced. Similarly, in ROC analyses, raw SF totals showed stronger discriminability between groups than either raw discrepancy scores (SF-LF) or discrepancy ratios (SF/LF). Age and cognitive status (MMSE) were the strongest individual predictors of performance. Findings suggest that AD entails quantitative declines in verbal fluency, but qualitatively similar patterns of performance relative to typically aging adults. Thus, SF declines in AD seem to be at least partially attributable to an exaggeration of the underlying mechanisms common to typical aging, and do not necessarily implicate semantic disintegration.

Effects of Anti-Parkinsonian Drugs on Verbal Fluency in Patients with Parkinson's Disease: A Network Meta-Analysis

Verbal fluency impairment is common in patients with Parkinson's disease (PD), but the effect of drugs on verbal fluency in PD patients has not been comprehensively evaluated. We conducted a network meta-analysis based on four online databases to compare the effect of drugs on verbal fluency in PD patients. This study was performed and reported according to PRISMA-NMA guidelines. In total, 6 out of 3707 articles (three RCTS and three cross-sectional studies) covering eight drug regimens were included (five for letter fluency, five for semantic fluency). In terms of letter fluency, the ranking of the overall efficacy of included drug regimens was: levodopa, levodopa combined with pramipexole, rotigotine, cabergoline, pramipexole, pergolide, but no drug regimen presented a significant advantage over the others. In terms of semantic fluency, the ranking of the overall efficacy of included drug regimens was: rotigotine, levodopa, cabergoline, pergolide, pramipexole, among which, levodopa alone (SMD = 0.93, 95%CI: 0.28-1.59) and rotigotine alone (SMD = 1.18, 95%CI: 0.28-2.09) were statistically superior to pramipexole, while no significant difference was identified between all the other drug regimens. Levodopa and rotigotine seem to be more appropriate choices for PD patients with verbal fluency impairment. Further study is needed to illustrate the efficacy of drugs on verbal fluency in PD patients.

Graph Theoretical Analysis of Semantic Fluency in Patients with Parkinson’s Disease

Semantic fluency is the ability to name items from a given category within a limited time, which relies on semantic memory, working memory, and executive function. Semantic disfluency is a common problem in Parkinson's disease (PD) and Alzheimer's disease (AD). We demonstrated a graph theoretical analysis of semantic fluency in patients with PD (N = 86), patients with AD (N = 40), and healthy controls (HC, N = 88). All participants completed a standard animal fluency test. Their verbal responses were recorded, transcripted, and transformed into directed speech graphs. Patients with PD generated fewer correct words than HC and more correct words than patients with AD. Patients with PD showed higher density, shorter diameter, and shorter average shortest path length than HC, but lower density, longer diameter, and longer average shortest path length than patients with AD. It suggests that patients with PD produced relatively smaller and denser speech graphs. Moreover, in PD, the densities of speech graphs correlated with the severity of non-motor symptoms, but not the severity of motor symptoms. The graph theoretical analysis revealed new features of semantic disfluency in patients with PD.

When it is not primary progressive aphasia: A scoping review of spoken language impairment in other neurodegenerative dementias

BACKGROUND

Progressive difficulties with spoken language occur across the spectrum of degenerative dementia. When not a primary presenting and dominant symptom, language difficulties may be overlooked in favor of more prominent cognitive, behavior, or motor deficits. The aim of this scoping review is to examine the extent and nature of the research evidence describing (1) the spoken language impairments found in non-language led dementias, (2) their impact on everyday living, and (3) the reported language interventions.

METHODS

We searched PubMed, MEDLINE, OVID-EMBASE, PsycINFO, and SpeechBITE using terms related to spoken language for the following dementia types: Parkinson's disease dementia (PDD), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), cortico-basal syndrome (CBS), behavior variant frontotemporal dementia (bvFTD), early-onset Alzheimer's disease (EOAD), posterior cortical atrophy (PCA), and motor neuron disease associated with FTD (MND+FTD). Risk of bias was assessed with the QualSyst tool.

RESULTS

Seventy-three eligible studies were included. A wide range of spoken language impairments were reported, involving both linguistic (e.g., syntactic processing) and other cognitive (e.g., sustained attention) underlying mechanisms. Although the severity of these deficits was scarcely reported, in some cases they manifested as non-fluent, dynamic, and global aphasias. No papers in the review described either the impact of these language impairments on everyday living or language therapies to treat them.

DISCUSSION

There is a need to understand better the level of disability produced by language impairment in people living with non-language-led dementias. Our findings suggest three calls for action: (1) research studies should assess the clinical relevance of any spoken language deficits examined, (2) both linguistic and cognitive underlying mechanisms should be fully described (to inform the design of effective language and behavioral interventions), and (3) trials of language therapy should be conducted in those groups of individuals where significant language impairment is proved.

Association Between REM Sleep Behavior Disorder and Cognitive Dysfunctions in Parkinson's Disease: A Systematic Review and Meta-Analysis of Observational Studies

Background: Rapid eye movement sleep behavior disorder (RBD) is thought to be a prodromal symptom of Parkinson's disease (PD). RBD is also thought to be involved in cognitive decline and dementia in PD. In PD, although the relationship between RBD and cognitive dysfunctions was confirmed by considerable studies, whether RBD was associated with distinct types of cognitive defects is worth of study. Objectives: This systematic review summarizes the evidence relating to cognitive dysfunction in PD patients with RBD (PD-RBD) and those without and explores their specificity to cognitive domains. Methods: A meta-analysis using a random-effects model was performed for 16 different cognitive domains, including global cognitive function, memory (long-term verbal recall, long-term verbal recognition, long-term visual recall, short-term spatial recall, and short-term verbal recall), executive function (general, fluid reasoning, generativity, shifting, inhibition, and updating), language, processing speed/complex attention/working memory, visuospatial/constructional ability, and psychomotor ability. The cognitive difference between the groups of patients was measured as a standardized mean difference (SMD, Cohen's d). PD-RBD patients were classified into Confirmed-RBD (definite diagnosis with polysomnography, PSG) and Probable-RBD (without PSG re-confirmation). In some domains, RBD patients could not be analyzed separately due to the exiguity of primary studies; this analysis refers to such RBD patients as "Mixed-RBD." Results: Thirty-nine studies with 6,695 PD subjects were finally included. Confirmed-RBD patients showed worse performance than those without in global cognitive function, long-term verbal recall, long-term verbal recognition, generativity, inhibition, shifting, language, and visuospatial/constructional ability; Probable-RBD, in global cognitive function and shifting; and Mixed-RBD, in long-term visual recall, short-term spatial recall, general executive function, and processing speed/complex attention/working memory. Conclusion: This meta-analysis strongly suggests a relationship between RBD, Confirmed-RBD in particular, and cognitive dysfunctions in PD patients. Early and routine screening by sensitive and targeted cognitive tasks is necessary for all PD-RBD patients because it may offer the therapeutic time window before they evolve to irreversible dementia.

Contribution of the Cerebellum and the Basal Ganglia to Language Production: Speech, Word Fluency, and Sentence Construction-Evidence from Pathology

Evidence reported in recent decades increasingly confirms that both the cerebellum and the basal ganglia, which are primarily involved in movement control, also have a significant role in a vast range of cognitive and affective functions. Evidence from pathology indicates that the disorders of some aspects of language production which follow damage of the cerebellum or respectively basal ganglia, i.e., disorders of speech, word fluency, and sentence construction, have identifiable neuropsychological profiles and that most manifestations can be specifically attributed to the dysfunctions of mechanisms supported by one or the other of these structures. The cerebellum and the basal ganglia are reciprocally interconnected. Thus, it is plausible that some disorders observed when damage involves one of these structures could be remote effects of abnormal activity in the other. However, in a purely clinical-neuropsychological perspective, primary and remote effects in the network are difficult to disentangle. Functional neuroimaging and non-invasive brain stimulation techniques likely represent the indispensable support for achieving this goal.

Sex Differences in Verbal Fluency Among Young Adults

Verbal fluency tasks have been used as tools to measure various cognitive processes, such as executive functions, memory, and language. Sex differences in verbal fluency performance have been mostly investigated in population studies. Little of this research has focused on young adults. The goal of this study was to assess the impact of sex and task category on word production and verbal strategies (i.e., cluster size and switches) in young adults. The phonemic (letter “k”, letter “f”) and semantic (animals, fruits, sharp objects) fluency measures were used. Men and women were compared in terms of the number of produced words and the use of verbal strategies (number of switches and mean cluster size controlled for produced words). Results revealed subtle sex differences in verbal fluency in young adults. Men performed slightly better in semantic fluency, producing more words, while there were no sex differences in verbal strategies. There were also no sex differences in word production and verbal strategies in the phonemic fluency tasks. Furthermore, there were differences in the number of produced words, mean cluster sizes, and switches between semantic tasks as well as between phonemic tasks. These results can be interpreted in the context of potential differences in mental lexicon and social roles. Moreover, our results suggest that assessment of verbal strategies and overall word production may be important in the context of sex differences in verbal fluency among young adults as well as in neuropsychological diagnosis

Letter Verbal Fluency in Spanish-, Basque-, and Catalan-Speaking Individuals: Does the Selection of the Letters Influence the Outcome?

Purpose The aim of this study was to compare Basque and Catalan bilinguals' performance on the letter verbal fluency test and determine whether significant differences are present depending on the letters used and the language of administration. Method The sample consisted of 87 Spanish monolinguals, 139 Basque bilinguals, and 130 Catalan bilinguals from Spain. Participants completed the letter verbal fluency test using the letters F, A, S, M, R, P, and E. Results Bilinguals scored higher on the letter verbal fluency test when they were tested in Spanish than in Basque or Catalan. No performance differences were found according to native language or dialects within Basque participants. Catalans with Spanish as their native language scored lower on the letter F compared to those who grew up speaking Catalan and Spanish. The suggested letters to use with Basque speakers are A, E, and B; the suggested letters to use with Catalan speakers are P, F, and M; and the suggested letters to use with Spanish speakers are M, R, and P. Conclusion Selecting appropriate stimuli depending on the language of testing is the first crucial step to assess verbal fluency and thus possible frontal lobe functioning impairment.

Executive Processes Underpin the Bilingual Advantage on Phonemic Fluency: Evidence From Analyses of Switching and Clustering

Bilinguals often show a disadvantage in lexical access on verbal fluency tasks wherein the criteria require the production of words from semantic categories. However, the pattern is more heterogeneous for letter (phonemic) fluency wherein the task is to produce words beginning with a given letter. Here, bilinguals often outperform monolinguals. One explanation for this is that phonemic fluency, as compared with semantic fluency, is more greatly underpinned by executive processes and that bilinguals exhibit better performance on phonemic fluency due to better executive functions. In this study, we re-analyzed phonemic fluency data from the Betula study, scoring outputs according to two measures that purportedly reflect executive processes: clustering and switching. Consistent with the notion that bilinguals have superior executive processes and that these can be used to offset a bilingual disadvantage in verbal fluency, bilinguals (35-65 years at baseline) demonstrated greater switching and clustering throughout the 15-year study period.

A cross-linguistic comparison of category and letter fluency: Mandarin and English

Verbal fluency tasks are widely applied in a variety of languages, but whether the quality and quantity of responses are comparable across structurally different writing systems is debatable. For example, since there are no letters in a logographic, non-alphabetic language such as Chinese, the mechanisms speakers use to generate a list of words in a letter fluency task might be structurally different than those used by speakers of alphabetic languages. In this study, we investigated lexical retrieval strategies and approaches in letter and category fluency tasks among monolingual Mandarin speakers compared to monolingual English speakers. We found that the responses of Mandarin speakers are both qualitatively and quantitatively different in letter fluency, and qualitatively different in category fluency. These results suggest that differences in task completion among non-English-speaking populations are important to consider when using this extensively utilised cognitive and linguistic measure in research and clinic.

Standing balance in individuals with Parkinson's disease during single and dual-task conditions

This study aimed to examine the differences in standing balance between individuals with Parkinson's disease (PD) and subjects without PD (control group), under single and dual-task conditions. A cross-sectional study was designed using a non-probabilistic sample of 110 individuals (50 participants with PD and 60 controls) aged 50 years old and over. The individuals with PD were in the early or middle stages of the disease (characterized by Hoehn and Yahr as stages 1-3). The standing balance was assessed by measuring the centre of pressure (CoP) displacement in single-task (eyes-open/eyes-closed) and dual-task (while performing two different verbal fluency tasks). No significant differences were found between the groups regarding sociodemographic variables. In general, the standing balance of the individuals with PD was worse than the controls, as the CoP displacement across tasks was significantly higher for the individuals with PD (p<0.01), both in anteroposterior and mediolateral directions. Moreover, there were significant differences in the CoP displacement based parameters between the conditions, mainly between the eyes-open condition and the remaining conditions. However, there was no significant interaction found between group and condition, which suggests that changes in the CoP displacement between tasks were not influenced by having PD. In conclusion, this study shows that, although individuals with PD had a worse overall standing balance than individuals without the disease, the impact of performing an additional task on the CoP displacement is similar for both groups.

Proficiency and Control in Verbal Fluency Performance across the Lifespan for Monolinguals and Bilinguals

The verbal fluency task is a widely used neuropsychological test of word retrieval efficiency. Both category fluency (e.g., list animals) and letter fluency (e.g., list words that begin with F) place demands on semantic memory and executive control functions. However letter fluency places greater demands on executive control than category fluency, making this task well-suited to investigating potential bilingual advantages in word retrieval. Here we report analyses on category and letter fluency for bilinguals and monolinguals at four ages, namely, 7-year-olds, 10-year-olds, young adults, and older adults. Three main findings emerged: 1) verbal fluency performance improved from childhood to young adulthood and remained relatively stable in late adulthood; 2) beginning at 10-years-old, the executive control requirements for letter fluency were less effortful for bilinguals than monolinguals, with a robust bilingual advantage on this task emerging in adulthood; 3) an interaction among factors showed that category fluency performance was influenced by both age and vocabulary knowledge but letter fluency performance was influenced by bilingual status.

Heterogeneity of letter fluency impairment and executive dysfunction in Parkinson's disease

Letter fluency deficits are commonly detected in non-demented Parkinson's disease (PD) patients but the underlying cause remains uncertain. We investigated the role of slowed processing speed and executive dysfunction. Eighteen nondemented PD participants and nineteen controls were compared on letter fluency using a fluency index (Fi); the average time to "think" of each word, a measure independent of motor speed. Video analyses produced thinking times to switch between word clusters and generate a word within a cluster. Correlational and regression analyses were undertaken with tests of processing speed and executive functioning. The PD group exhibited significantly longer fluency indices than controls across all components. Performance on tests of executive functioning explained a significant proportion of variance whereas performance in processing speed tests did not. Moreover, PD participants with an executive functioning impairment showed significantly worse switching fluency indices only compared with Controls and PD participants without executive dysfunction. PD participants with executive dysfunction exhibited a disproportionate impairment in the time taken to switch between clusters than to think of words within clusters. Executive functioning contributed to fluency performance more than processing speed. Cognitive heterogeneity and motor slowing, may mask the profile of cognitive dysfunction in neurodegenerative disease.

Quantitative analysis of language production in Parkinson's disease using a cued sentence generation task

The present study examined language production skills in Parkinson's disease (PD) patients. A unique cued sentence generation task was created in order to reduce demands on memory and attention. Differences in sentence production abilities according to disease severity and cognitive impairments were assessed. Language samples were obtained from 20 PD patients and 20 healthy control participants matched for age, sex and educational level. In addition, a cognitive test for verbal memory and resistance to cognitive interference was administered. Statistical comparisons revealed significant language changes in an advanced stage of the disease. Advanced PD patients showed a reduction in lexical diversity in notional verbs, which was absent in nouns. Cognitive dysfunctions such as impaired verbal memory are suggested to contribute to the typical noun/verb dissociation in PD patients. In addition, advanced PD patients produced more semantic perseverations, which may be related to set-switching problems. In conclusion, whether language disturbances in PD are the result of non-linguistic cognitive dysfunctions or reflect pure language deficits exacerbated by cognitive impairments, remains a matter of debate. However, the negative impact of cognitive dysfunctions may be important.

Same modulation but different starting points: performance modulates age differences in inferior frontal cortex activity during word-retrieval

The neural basis of word-retrieval deficits in normal aging has rarely been assessed and the few previous functional imaging studies found enhanced activity in right prefrontal areas in healthy older compared to younger adults. However, more pronounced right prefrontal recruitment has primarily been observed during challenging task conditions. Moreover, increased task difficulty may result in enhanced activity in the ventral inferior frontal gyrus (vIFG) bilaterally in younger participants as well. Thus, the question arises whether increased activity in older participants represents an age-related phenomenon or reflects task difficulty effects. In the present study, we manipulated task difficulty during overt semantic and phonemic word-generation and used functional magnetic resonance imaging to assess activity patterns in the vIFG in healthy younger and older adults (N = 16/group; mean age: 24 vs. 69 years). Both groups produced fewer correct responses during the more difficult task conditions. Overall, older participants produced fewer correct responses and showed more pronounced task-related activity in the right vIFG. However, increased activity during the more difficult conditions was found in both groups. Absolute degree of activity was correlated with performance across groups, tasks and difficulty levels. Activity modulation (difficult vs. easy conditions) was correlated with the respective drop in performance across groups and tasks. In conclusion, vIFG activity levels and modulation of activity were mediated by performance accuracy in a similar way in both groups. Group differences in the right vIFG activity were explained by performance accuracy which needs to be considered in future functional imaging studies of healthy and pathological aging.

Are verbal fluency and nonliteral language comprehension deficits related to depressive symptoms in Parkinson's disease?

Depression in Parkinson's disease (PD) is frequently associated with executive deficits, which can influence nonliteral comprehension and lexical access. This study explores whether depressive symptoms in PD modulate verbal fluency and nonliteral language comprehension. Twelve individuals with PD without depressive symptoms, 13 with PD and depressive symptoms (PDDSs), and 13 healthy controls completed a semantic and phonemic verbal fluency task and an indirect speech acts comprehension task. All groups had the same performance in the phonemic fluency task while the PDDS group was impaired in the semantic task. For the indirect speech act comprehension task, no difference was observed between the groups. However, the PDDS group had difficulty answering direct speech act questions. As some language impairments in PD become apparent when depressive symptoms are associated with the disease, it would appear to be important to take the presence of depressive symptoms into account when evaluating language abilities in PD.

Not just semantics: strong frequency and weak cognate effects on semantic association in bilinguals

To investigate the possibility that knowledge of two languages influences the nature of semantic representations, bilinguals and monolinguals were compared in a word association task. In Experiment 1, bilinguals produced less typical responses relative to monolinguals when given cues with a very common associate (e.g., given bride, bilinguals said "dress" instead of "groom"). In Experiment 2, bilinguals produced responses as typical as those of monolinguals when given cues with high-frequency associates, but not when given cues with low-frequency associates. Bilinguals' responses were also affected, to a certain extent, by the cognate status of the stimulus word pairs: They were more similar to monolinguals' responses when the cue and its strongest associate were both cognates (e.g., minute-second is minuto-segundo in Spanish), as opposed to both being noncognates. Experiment 3 confirmed the presence of a robust frequency effect on bilingual but not on monolingual association responses. These findings imply a lexical locus for the bilingual effect on association responses and reveal the association task to be not quite as purely semantic as was previously assumed.

Creativity in Parkinson's disease as a function of right versus left hemibody onset

OBJECTIVE

Creativity is heavily dependent on divergent thinking and divergent thinking appears to be strongly dependent on fontal lobe function. Since patients with Parkinson's disease (PD) often have evidence of frontal lobe dysfunction we wanted to learn if these patients have a reduction of creativity, as well as learning if the side of onset (right versus left) influences the type (verbal versus visuospatial) of decrement in creativity.

DESIGN

Participants of this study were patients with right (RHO) or left (LHO) onset PD as well as matched controls. All subjects were given the Abbreviated Torrance Test of Creative Thinking for Adults (ATTA), a widely used test to assess creativity that examines Fluency, Originality, Flexibility and Elaboration. Subjects were also assessed with the Controlled Word Association Test (COWAT).

RESULTS/CONCLUSIONS

When compared to controls the patients with RHO, but not LHO, had a decrease of verbal creative fluency. Patients with PD often have a decrease on the COWAT, but performance on the COWAT did not differ between the RHO and the LHO patients. This suggests that patients with PD who have RHO have a decrease in verbal creativity and this decrement does not appear to be related to decreased fluency.

Spreading activation of lexical-semantic networks in Parkinson's disease

Although dopamine may act as a neuromodulator of spreading activation within semantic networks, this role of dopamine in lexical networks has not been investigated. Hence, we sought to investigate the effects of Parkinson's disease (PD), which is associated with dopamine depletion, on spreading activation in the lexical networks. Ten Parkinson's disease patients and 11 normal controls performed the controlled oral word association test and the average word frequency for their responses was calculated and used as an index of spreading activation. The PD patients exhibited a lower average word frequency, suggesting increased spreading activation, and a significant relationship between the strength of the initial activation and subsequent extent of spreading activation. Most patients were taking dopaminergic medication and future studies may benefit from examining the changes in spreading activation in lexical networks in PD patients on versus off medication or in healthy controls taking either a placebo or a dopaminergic medication. Although these alterations in lexical access might be related to the reduction of dopamine, one of the hallmarks of PD, these patients also have alterations of other neurotransmitter systems and further studies are needed to more clearly identify the role played by these neurotransmitter on lexical access.

Verbal fluency in bilingual Spanish/English Alzheimer's disease patients

Studies have demonstrated that in verbal fluency tests, monolinguals with Alzheimer's disease (AD) show greater difficulties retrieving words based on semantic rather than phonemic rules. The present study aimed to determine whether this difficulty was reproduced in both languages of Spanish/English bilinguals with mild to moderate AD whose primary language was Spanish. Performance on semantic and phonemic verbal fluency of 11 bilingual AD patients was compared to the performance of 11 cognitively normal, elderly bilingual individuals matched for gender, age, level of education, and degree of bilingualism. Cognitively normal subjects retrieved significantly more items under the semantic condition compared to the phonemic, whereas the performance of AD patients was similar under both conditions, suggesting greater decline in semantic verbal fluency tests. This pattern was produced in both languages, implying a related semantic decline in both languages. Results from this study should be considered preliminary because of the small sample size.

Effect of presentation modality on immediate and delayed recall in individuals with Alzheimer's disease

Episodic memory (EM) deficits are the hallmark of Alzheimer's disease (AD). Story-retelling tasks are particularly sensitive to EM impairments and require participants to recall a short story immediately and after a delay. The purpose of this study was to determine whether presentation modality influences story recall in AD participants. Thirty AD participants and 30 healthy elders recalled short stories in (a) auditory, (b) visual, and (c) combined auditory-visual modalities. Recall was assessed immediately as well as after 15- and 30-min delays. Presentation modality significantly influenced story recall in AD participants. AD participants demonstrated better recall after silently reading a story than after hearing an examiner tell the story or simultaneously hearing and reading the story. Clinical implications of these results are discussed.

Verbal fluency deficits in Parkinson's disease: a meta-analysis

A meta-analysis of 68 studies with a total of 4644 participants was conducted to investigate the sensitivity of tests of verbal fluency to the presence of Parkinson's disease (PD) relative to healthy controls. Both phonemic and semantic fluency were moderately impaired but neither deficit qualified as a differential deficit relative to verbal intelligence or psychomotor speed. However, PD patients were significantly more impaired on semantic relative to phonemic fluency (rs =.37 vs.33, respectively), and confrontation naming, a test of semantic memory that imposes only minimal demands upon cognitive speed and effortful retrieval, was associated with a deficit that was of a comparable magnitude to the deficits upon each of these types of fluency. Thus, the disorder appears to be associated with particular problems with semantic memory. Tests that impose heavy demands upon switching may also be disproportionately affected. Demented and non-demented PD patients differ quantitatively but not qualitatively in terms of the relative prominence of deficits on tests of phonemic and semantic fluency. However, patients with dementia of the Alzheimer's type and demented PD patients can be differentiated from one another by the relative magnitude of deficits upon these two measures.

Category size effects in semantic and letter fluency in Alzheimer's patients

Many studies have found that patients with Alzheimer's disease (AD) perform significantly worse than normal controls on verbal fluency tasks. Moreover, some studies have found that AD patients' deficits compared to controls are more severe for semantic fluency (e.g., vegetables) than for letter fluency (e.g. words that begin with F). These studies, however, have not taken category size into account. A comparison of AD patients and age-matched controls on three semantic and three letter categories revealed that both the size and type of a category significantly predicted AD patients' deficits on verbal fluency tasks. These results suggest that the verbal fluency of AD patients will be most attenuated on large semantic categories.

Working Memory and Perseveration in Verbal Fluency

Letter and semantic fluency tasks are often used in neuropsychological assessment and are sensitive to many conditions. Performance is assessed by correct responses and errors, including perseverations. Healthy young adults performed letter and semantic fluency tasks. One group performed these tasks in the conventional manner; 2 other groups performed them while maintaining memory loads. The memory loads consisted either of words from the same category as the fluency task or of words from a different category. The results showed little effect of memory loads on correct responses but significant effects of memory load on perseveration rates: Same-category loads resulted in higher rates, especially in letter fluency. The results are discussed in terms of frontal lobe function in verbal fluency.

Quantitative und qualitative Analysen von verbalen Flüssigkeitsaufgaben bei Parkinsonpatienten

Zusammenfassung: Bei nicht dementen Patienten mit Morbus Parkinson (PK) mehren sich die Hinweise auf spezifische neuropsychologische Funktionseinbußen. Insbesondere bei Wortflüssigkeitsaufgaben wird kontrovers diskutiert, ob und bei welchem Aufgabentypus PK-Patienten Minderleistungen erbringen. In der vorliegenden Studie wurden die Leistungen von 26 nicht dementen PK-Patienten bei semantischen und formallexikalischen Wortflüssigkeitsaufgaben sowie einer Generierungsaufgabe nach Wortarten (Adjektive) untersucht und denen einer Kontrollgruppe (KG) von 24 hirngesunden Personen gegenübergestellt. Während die PK-Patienten bei sämtlichen Aufgaben signifikant niedrigere Wortraten erbrachten, ergab die qualitative Untersuchung der Nennungen keine Gruppenunterschiede bezüglich Clusterbildung, kategorialer Verteilung und Variationsbreite der Nennungen. Semantische Wortflüssigkeitsaufgaben erwiesen sich als besonders sensible Indikatoren für neuropsychologische Funktionseinbußen bei nicht dementen PK-Patienten.

A neuropsychological comparison of demented and nondemented patients with Parkinson's disease

The strength and sensitivity of neuropsychological test findings in patients with Parkinson's disease (PD) was reviewed using meta-analytic principles to provide a basis of comparison of deficits in nondemented and demented patients with PD. The review revealed significant relationships among duration of disease, physical disability, and cognitive impairment in nondemented patients, and qualitative and quantitative differences in the pattern of neuropsychological test impairments between nondemented and demented patients with PD. The disparate profiles of neuropsychological impairment in nondemented and demented patients may indeed reflect disease progression in keeping with the significant clinical correlations in nondemented patients. That is, as the duration of the disease endures, it appears that performance on tasks of delayed recall deteriorates first, followed by performance on measures of manual dexterity, cognitive flexibility, and abstraction.