Verbal Fluency Tests: Normative Data Stratified by Age and Education in an Istanbul Sample

Semantic verbal fluency in native speakers of Turkish: a systematic review of category use, scoring metrics and normative data in healthy individuals

INTRODUCTION

Semantic verbal fluency (SVF) is a widely used measure of frontal executive function and access to semantic memory. SVF scoring metrics include the number of unique words generated, perseverations, intrusions, semantic cluster size and switching between clusters, and scores vary depending on the language the test is administered in. In this paper, we review the existing normative data for Turkish, the main metrics used for scoring SVF data in Turkish, and the most frequently used categories.

METHOD

We conducted a systematic review of peer-reviewed papers using Medline, EMBASE, PsycInfo, Web of Science, and two Turkish databases, TR-Dizin and Yok-Tez. Included papers contained data on the SVF performance of healthy adult native speakers of Turkish, and reported the categories used. Versions of the SVF that required participants to alternate categories were excluded. We extracted and tabulated demographics, descriptions of groups, metrics used, categories used, and sources of normative data. Studies were assessed for level of detail in reporting findings.

RESULTS

1400 studies were retrieved. After deduplication, abstract, full text screening, and merging of theses with their published versions, 121 studies were included. 114 studies used the semantic category "animal", followed by first names (N = 14, 12%). All studies reported word count. More complex measures were rare (perseverations: N = 12, 10%, clustering and switching: N = 5, 4%). Four of seven normative studies reported only word count, two also measured perseverations, and one reported category violations and perseverations. Two normative studies were published in English.

CONCLUSIONS

There is a lack of normative Turkish SVF data with more complex metrics, such as clustering and switching, and a lack of normative data published in English. Given the size of the Turkish diaspora, normative SVF data should include monolingual and bilingual speakers. Limitations include a restriction to key English and Turkish databases.

Turkish adaptation, reliability, and validity of the detection test for language impairments in adults and the aged

There is no quick, valid, and reliable screening tool in Turkish that can be used for screening language disorders associated with major neurocognitive disorders (MND). To fill this gap, we designed three distinct studies. In the first study, we adapted the Detection Test for Language Impairments in Adults and the Aged into the Turkish language (DTLA-Tr). In the second study, we collected data from 175 Turkish individuals to determine the normative data of the DTLA-Tr. In the last study, we investigated the psychometric properties of the DLTA-Tr by comparing 17 healthy individuals with 17 patients with Alzheimer's disease and determining its test-retest reliability. As a result of Study 1, the DTLA was adapted to the Turkish adult population. In Study 2, the normative data of the DTLA-Tr were provided. The results of this study indicated a positive correlation between educational level and DTLA-Tr total score. The results of Study 3 showed that the DTLA-Tr has high predictive validity and good test-retest reliability. The DTLA-Tr is a valid and reliable tool for assessing language abilities in both adults and the elderly. The findings of this study have significant implications for the evaluation of language in Turkish-speaking patients with MND.

Comparison of verbal fluency performance in Kannada-speaking adults with and without euthymic bipolar disorder type 1

Individuals with euthymic bipolar disorder (BD) type I exhibit deficits in executive functions. Although less explored in the BD population, the tasks of verbal fluency (VF) have shown great potential in understanding semantic organization. This study provides an extensive exploration across the letter and semantic VF tasks in 27 demographically matched euthymic BD-I and healthy controls (HC). The groups were compared on measures of the total number of correct words (TNCW), temporal pattern analysis, number of clusters (NC), mean cluster size (MCS), number of switches (NS), and error pattern. An overall reduction in letter fluency scores (the TNCW, number of switches, and NC) as compared to semantic fluency scores was noted for both groups, with a significantly greater decrease in the BD-1 group. The MCS and temporal pattern were relatively similar across the two groups. The influence of education with no gender difference was observed between groups with error types prevalent in both groups. The study findings call attention toward assessing the VF performance in persons with BD in terms of error production and the strategies employed (clustering-switching).

The effect of subthreshold depressive symptoms on cognitive functions and peripheral biomarkers in bipolar disorder

OBJECTIVE

A global approach to factors responsible for functional impairment in patients with BD is necessary.

METHOD

Ninety-three euthymic patients with BD [49 patients with SD (subthreshold depression) and 44 patients without SD] and 48 healthy controls were invited for evaluation of demographic, clinical, and cognitive characteristics. To define SD, the lower limit was HDRS ≥4 points and the upper limit was HDRS <9 points. Stroop test, California verbal learning test, digit-span test, controlled word association test, and clock drawing test were performed. Serum BDNF levels were measured. Additionally in the BD group; blood drug (lithium, valproic acid), leukocyte, C-reactive protein (CRP), TSH, and vitamin B12 levels were measured.

RESULTS

We found no difference between serum BDNF levels of BD (n = 93) and controls. The cognitive performances of the BD group were worse than the control group (p < 0.001). Attention, working memory, and stroop performance of patients with SD were worse than patients without SD (p < 0.05). Verbal fluency, stroop test, and planning performance decreased as serum CRP level increased in patients with BD (p < 0.05).

CONCLUSIONS

Although the patient group with SD was in euthymia, their cognitive performance was worse than the group without SD. Poor cognitive performance in BD was associated with serum CRP levels.

Sözel Akıcılık Testleri, Alzheimer Hastalığı klinik ölçütlerine göre evrelenmiş demans ve HKB ayrımında yarar sağlayabilir

Demans tarama ve tanısı için klinik pratikte sıklıkla kısa tarama testleri kullanılmaktadır. Mini Mental Durum Testi (MMDT) en sık kullanılan testlerin başında gelmektedir. MMDT’nin demans için duyarlı olduğu bilinmektedir. Ancak, sağlıklı yaşlanma ile demans arasında bir geçiş evresi olarak kabul edilen Hafif Kognitif Bozukluk (HKB)’un ayırt edilmesinde ve Alzheimer Hastalığı tipi demans (AHD) ile HKB’nin ayırıcı tanısında MMDT çoğu zaman yeterli olmamaktadır. Kısa sürede uygulanabilen sözel akıcılık testleri (semantik ve fonemik) MMDT’ye alternatif ya da MMDT ile kullanıldığında HKB ve AH’nin erken evreleri için tanısal doğruluğu daha yüksek bir tarama testi elde edilebilir. Bu çalışmanın amacı MMDT, semantik ve fonemik akıcılık testlerinin ROC eğrisi analizleri ile belirlenen duyarlılık, özgüllük ve kesme puanı değerlerinin sunulmasıdır. Çalışmaya yaş-eğitim-cinsiyet açısından uyumlu 72 sağlıklı birey, 72 HKB ve 72 AHD’li birey dahil edilmiştir. Çalışmanın bulguları MMDT’nin sağlıklı bireyleri ayırt etmede semantik ve fonemik akıcılıktan daha güçlü olduğunu, ancak HKB ve AH ayrımında özgüllüğünün semantik akıcılıktan düşük olduğunu göstermektedir. Tanı doğruluğunun artırılması için kısa zamanda uygulanabilen sözel akıcılık testlerinin, özellikle semantik akıcılık testinin klinik pratiğe eklenmesi yararlı olabilir.

Towards the Validation of Executive Functioning Assessments: A Clinical Study

Neuropsychological assessment needs a more profound grounding in psychometric theory. Specifically, psychometrically reliable and valid tools are required, both in patient care and in scientific research. The present study examined convergent and discriminant validity of some of the most popular indicators of executive functioning (EF). A sample of 96 neurological inpatients (aged 18-68 years) completed a battery of standardized cognitive tests (Raven's matrices, vocabulary test, Wisconsin Card Sorting Test, verbal fluency test, figural fluency test). Convergent validity of indicators of intelligence (Raven's matrices, vocabulary test) and of indicators of EF (Wisconsin Card Sorting Test, verbal fluency test, figural fluency) were calculated. Discriminant validity of indicators of EF against indicators of intelligence was also calculated. Convergent validity of indicators of intelligence (Raven's matrices, vocabulary test) was good (r_xtyt = 0.727; R² = 0.53). Convergent validity of fluency indicators of EF against executive cognition as indicated by performance on the Wisconsin Card Sorting Test was poor (0.087 ≤ r_xtyt ≤ 0.304; 0.008 ≤ R² ≤ 0.092). Discriminant validity of indicators of EF against indicators of intelligence was good (0.106 ≤ r_xtyt ≤ 0.548; 0.011 ≤ R² ≤ 0.300). Our conclusions from these data are clear-cut: apparently dissimilar indicators of intelligence converge on general intellectual ability. Apparently dissimilar indicators of EF (mental fluency, executive cognition) do not converge on general executive ability. Executive abilities, although non-unitary, can be reasonably well distinguished from intellectual ability. The present data contribute to the hitherto meager evidence base regarding the validity of popular indicators of EF.