Word‐finding difficulties in Parkinson's disease: Complex verbal fluency, executive functions and other influencing factors

Abstract

Background Persons with Parkinson's disease (PD) frequently report word‐finding difficulties. Many of the established tests are, however, insufficient in detecting mild cases of such symptoms. Results from earlier research have suggested that controlled oral word association tests (COWATs) with high demands on cognitive processing resources could prove helpful in detecting the more subtle (language‐related) problems seen in neurological disorders such as PD. Aims First, to examine whether persons with PD (PwPD) differ in performance on different types of COWATs compared with non‐brain‐damaged controls. Second, to investigate possible relationships between executive functions and the novel complex oral semantic fluency (COSEF) task performance scores in the PwPD group. Third, to investigate whether age, years of education, severity of motor symptoms and self‐perceived severity of word‐finding difficulties influenced the COSEF task results. Methods & Procedures A total of 17 PwPD participated in the study. Their results were compared with a matched control group (n = 17) at both group and individual levels. One phonemic and two types of semantic COWATs were used. Correlations between the COSEF task and executive function results, age, education and severity of motor symptoms were analysed in the PwPD group. Outcomes & Results The PwPD group had significantly lower scores on the COSEF task compared with the control group, but not on the other COWATs. A variation in the results was seen on an individual level. In the PwPD group, large significant correlations were seen between the COSEF task and verbally based tasks measuring working memory and cognitive flexibility. Both age and education, but neither self‐perceived severity of word‐finding difficulties nor motor symptoms, were correlated with the COSEF task result in the group of PwPD. Conclusions & Implications The results are in line with the predictions that a relatively more cognitive demanding COWAT such as the COSEF task could prove valuable when assessing word‐finding difficulties in PD in research and clinical assessment. What this paper adds What is already known on the subjectVarying degrees of word‐finding difficulties are a common symptom in PD and may affect everyday communication. Discreet word‐finding difficulties can be hard to detect with the established language assessment tools. What this paper adds to existing knowledgeThis study adds insights into how PwPD perform on different types of COWATs compared with a control group. It also sheds light on the relationships between a novel, more cognitive complex COWAT and executive functions in PD. What are the potential or actual clinical implications of this work?More cognitively complex COWATs can contribute significantly to the assessment of discreet word‐finding difficulties, but it is important to include a thorough anamnesis regarding language and communication in PwPD.

Neurocognitive correlates of semantic memory navigation in Parkinson’s disease

“…Verbal semantics is often overlooked in routine PD assessments, echoing the classical view that language is unaffected in PD 74 . However, accruing evidence attests to the relevance of semantic measures for patient characterization, differential diagnosis, phenotyping, and monitoring 2 – 4 , 10 – 14 , 47 , 75 , 76 . Word-property analyses could fruitfully complement more expensive and invasive markers (such as those offered by biochemical, genetic, and neuroimaging tests) 77 and more typical approaches to word-production assessments (e.g., valid response counts in verbal fluency tasks) 12 .…”

“…Yet, we acknowledge that this precludes claims on our findings’ cross-linguistic generalizability. Promisingly, PD studies have shown semantic memory deficits in several other languages 14 , 30 , 31 , 33 – 35 , 37 , 38 , 42 and relevant normative databases exist for many of them 95 – 100 . This scenario paves the way for informative replications of our approach across diverse speech communities.…”

“…Core motor symptoms in early stages of PD are typically accompanied by cognitive dysfunctions 8 , including semantic anomalies 3 , 9 . These range from difficulties with concept association 10 , retrieval 11 , and comprehension 4 , 10 , 12 , 13 to word finding and definition deficits 14 . Such impairments can emerge preclinically; 2 , 15 discriminate between patients with different cognitive profiles 3 and medication status; 16 and correlate with abnormalities in frontostriatal 17 , 18 , perisylvian 19 , prefrontal, and anterior cingulate 20 , 21 hubs along the sensorimotor, semantic, and salience networks.…”

Language impairments in seropositive and seronegative autoimmune encephalitis

“…Further, working memory has been implicated in verbal fluency [ 21 ] and confrontation naming [ 18 ], whereby confrontation naming requires temporarily storing and manipulating information, such as aspects of the image. Semantic fluency requires temporarily storing and manipulating retrieved words, tracking already given words, and inhibiting incorrect works, all while maintaining a search strategy.…”

Normative Data for Single-Letter Controlled Oral Word Association Test in Older White Australians and Americans, African-Americans, and Hispanic/Latinos

“…Performance on the COWAT is known to be influenced by various factors, including gender, age, education, and ethnicity [28,29]. It is also sensitive to a range of neuropsychiatric disorders and neurologic conditions [30][31][32], and has been recognized as an effective tool for detecting brain dysfunction, particularly in relation to abnormalities in the frontal lobes [33,34]. Indeed, decreased COWAT performance is associated with the early stages of dementia [10,35].…”