Longitudinal study of performance on the Ruff Figural Fluency Test in persons aged 35 years or older

Measures of figural fluency: Relationship to neuropsychological variables and traumatic brain injury severity

Figural fluency tests were originally developed as a measure of right frontal lobe integrity and are presently a standard component of neuropsychological evaluation. To better understand the clinical interpretation of figural fluency scores (design output and perseverative errors), the current study investigated two trials from the Ruff Figural Fluency Test (RFFT) and their correlations with other neuropsychological variables in examinees who were being evaluated for cognitive difficulties (N = 84). Design output was significantly correlated (r_s > .4) with psychomotor speed, non-verbal memory, and false positive recognition errors on a verbal memory test, while perseverative errors did not show a significant correlation with these variables or with design output. Design output also showed a significant correlation with phonemic fluency (r_s > .3) as well as correlations (r_s > .25) with semantic fluency and intellectual functioning. In a sample of examinees with mild (n = 33), complicated-mild (n = 11), and moderate-severe (n = 16) traumatic brain injuries (TBI), group differences in design output did not reach significance, whereas perseverative errors were significantly related to the severity of injury. This study suggests that design output and perseverative errors on figural fluency may be separate measures, and their clinical interpretations are discussed.

The validity and reliability of a digital Ruff Figural Fluency Test (RFFT)

BACKGROUND

The Ruff Figural Fluency Test (RFFT) is a valid but time-consuming and labour-intensive cognitive paper-and-pencil test. A digital RFFT was developed that can be conducted independently using an iPad and Apple Pencil and RFFT scores are computed automatically. We investigated the validity and reliability of this digital RFFT.

METHODS

We randomly allocated participants to the digital or paper-and-pencil RFFT. After the first test, the other test was performed immediately (cross-over). Participants were invited for a second digital RFFT 1 week later. For the digital RFFT, an (automatic) algorithm and two independent raters (criterion standard) assessed the number of unique designs (UD) and perseverative errors (PE). These raters also assessed the paper-and-pencil RFFT. We used Intraclass correlation coefficients (ICC), sensitivity, specificity, %-agreement, Kappa, and Bland-Altman plots.

RESULTS

We included 94 participants (mean (SD) age 39.9 (14.8), 73.4% follow-up). Mean (SD) UD and median (IQR) PE of the digital RFFT were 84.2 (26.0) and 4 (2-7.3), respectively. Agreement between manual and automatic scoring of the digital RFFT was high for UD (ICC = 0.99, 95% CI 0.98, 0.99, sensitivity = 0.98; specificity = 0.96) and PE (ICC = 0.99, 95% CI 0.98, 0.99; sensitivity = 0.90, specificity = 1.00), indicating excellent criterion validity. Small but significant differences in UD were found between the automatic and manual scoring (mean difference: - 1.12, 95% CI - 1.92, - 0.33). Digital and paper-and-pencil RFFT had moderate agreement for UD (ICC = 0.73, 95% CI 0.34, 0.87) and poor agreement for PE (ICC = 0.47, 95% CI 0.30, 0.62). Participants had fewer UD on the digital than paper-and-pencil RFFT (mean difference: - 7.09, 95% CI - 11.80, - 2.38). The number of UD on the digital RFFT was associated with higher education (Spearman's r = 0.43, p < 0.001), and younger age (Pearson's r = - 0.36, p < 0.001), showing its ability to discriminate between different age categories and levels of education. Test-retest reliability was moderate (ICC = 0.74, 95% CI 0.61, 0.83).

CONCLUSIONS

The automatic scoring of the digital RFFT has good criterion and convergent validity. There was low agreement between the digital RFFT and paper-and-pencil RFFT and moderate test-retest reliability, which can be explained by learning effects. The digital RFFT is a valid and reliable instrument to measure executive cognitive function among the general population and is a feasible alternative to the paper-and-pencil RFFT in large-scale studies. However, its scores cannot be used interchangeably with the paper-and-pencil RFFT scores.

Treatable Vascular Risk and Cognitive Performance in Persons Aged 35 Years or Older: Longitudinal Study of Six Years

Background

Poor cognitive performance is associated with high vascular risk. However, this association is only investigated in elderly. As neuropathological changes precede clinical symptoms of cognitive impairment by several decades, it is likely that cognitive performance is already associated with vascular risk at middle-age.

Objectives

To investigate the association of cognitive performance with treatable vascular risk in middle-aged and old persons.

Design

Longitudinal study with three measurements during follow-up period of 5.5 years.

Setting

City of Groningen, the Netherlands.

Participants

Cohort of 3,572 participants (age range, 35–82 years; mean age, 54 years; men, 52%).

Exposure

Treatable vascular risk as defined by treatable components of the Framingham Risk Score for Cardiovascular Disease at the first measurement (diabetes mellitus, smoking, hypercholesterolemia and hypertension).

Measurements

Change in cognitive performance during follow-up. Cognitive performance was measured with Ruff Figural Fluency Test (RFFT) and Visual Association Test (VAT), and calculated as the average of the standardized RFFT and VAT score per participant.

Results

The mean (SD) cognitive performance changed from 0.00 (0.79) at the first measurement to 0.15 (0.83) at second measurement and to 0.39 (0.82) at the third measurement (Ptrend<0.001). This change was negatively associated with treatable vascular risk: the change in cognitive performance between two measurements decreased with 0.004 per one-point increment of treatable vascular risk (95%CI, -0.008 to 0.000; P=0.05) and with 0.006 per one-year increment of age (95%CI, -0.008 to -0.004; P<0.001).

Conclusions

Change in cognitive performance was associated with treatable vascular risk in persons aged 35 years or older.

Electronic Supplementary Material

Supplementary material is available for this article at 10.14283/jpad.2018.47 and is accessible for authorized users.

Pharmacological treatment of increased vascular risk and cognitive performance in middle-aged and old persons: six-year observational longitudinal study

Background

Lowering vascular risk is associated with a decrease in the prevalence of cardiovascular disease and dementia. However, it is still unknown whether lowering of vascular risk with pharmacological treatment preserves cognitive performance in general. Therefore, we compared the change in cognitive performance in persons with and without treatment of vascular risk factors.

Methods

In this longitudinal observational study, 256 persons (mean age, 58 years) were treated for increased vascular risk during a mean follow-up period of 5.5 years (treatment group), whereas 1678 persons (mean age, 50 years) did not receive treatment (control group). Cognitive performance was three times measured during follow-up using the Ruff Figural Fluency Test (RFFT) and Visual Association Test (VAT), and calculated as the average of standardized RFFT and VAT score per participant. Because treatment allocation was nonrandomized, additional analyses were performed in demographic and vascular risk-matched samples and adjusted for propensity scores.

Results

In the treatment group, mean (SD) cognitive performance changed from − 0.30 (0.80) to − 0.23 (0.80) to 0.02 (0.87), and in control group, from 0.08 (0.77) to 0.24 (0.79) to 0.49 (0.74) at the first, second and third measurement, respectively (p_trend < 0.001). After adjustment for demographics and vascular risk, the change in cognitive performance during follow-up was not statistically significantly different between the treatment and control group: mean estimated difference, − 0.10 (95%CI − 0.21 to 0.01; p = 0.08). Similar results were found in matched samples and after adjustment for propensity score.

Conclusion

Change in cognitive performance during follow-up was similar in treated and untreated persons. This suggests that lowering vascular risk preserves cognitive performance.

Differential role of prefrontal, temporal and parietal cortices in verbal and figural fluency: Implications for the supramodal contribution of executive functions

Verbal and figural fluency are related to executive functions (EFs), but the extent to which they benefit from executive resources and their respective cortical representations is not clear. Moreover, different brain areas and cognitive functions are involved in fluency processing. This study investigated effects of modulation of cortical excitability in the left dorsolateral prefrontal cortex (l-DLPFC), left temporal area and right posterior parietal cortex (r-PPC) with transcranial direct current stimulation (tDCS), on verbal and figural fluency. Fifteen healthy adult participants received anodal l-DLPFC (F3), anodal left temporal (T3), anodal r-PPC (P4) and sham tDCS (15 min, 1.5 mA). After five minutes of stimulation, participants underwent the verbal fluency (i.e., semantic and phonemic fluency tasks) and figural fluency tasks. Participants significantly generated more words with phonemic cues during anodal l-DLPFC tDCS and more words with semantic cues during both anodal left temporal and anodal l-DLPFC tDCS. In contrast, they generated more unique figures under anodal r-PPC and anodal l-DLPFC tDCS. Our results implicate that prefrontal regions and EFs are shared anatomical correlates and cognitive processes relevant for both, verbal and figural fluency (supramodal contribution of DLPFC activation), whereas r-PPC and left temporal cortex are more specifically involved in figural and semantic fluency (modality-specific contribution).

Comparison of cognitive functioning as measured by the Ruff Figural Fluency Test and the CogState computerized battery within the LifeLines Cohort Study

Background

The Ruff Figural Fluency Test (RFFT; a pencil and paper test) and the CogState (a computerized cognitive test battery) are well-validated and suitable tests to evaluate cognitive functioning in large observational studies at the population level. The LifeLines Cohort Study includes the RFFT as baseline measurement and incorporated the CogState as replacement for the RFFT at follow-up. It is unknown how these two tests relate to each other. Therefore, the aim of this study is to examine the correlation between the RFFT and the CogState and the impact of demographic characteristics on this association.

Methods

A subcohort of the LifeLines Cohort Study, a large population based cohort study, participated in this study. Correlations between the RFFT and six subtasks of the CogState were examined. Subgroup analyses were performed to investigate the influence of age, education, and gender on the results. With sensitivity analyses we investigated the influence of computer experience and (physical) impairments.

Results

A total of 509 participants (mean age (SD): 53 years (14.6); range 18–87 years) participated in this study. All correlations between the RFFT and the CogState were statistically significant (except for the correlation between the RFFT error ratio and the CogState One Back Task), ranging from -0.39 to 0.28. Stratifying the analyses for age, education, and gender did not substantially affect our conclusions. Sensitivity analyses showed no substantial influence of level of computer experience or (physical) impairments.

Conclusions

Correlations found in the present study were only weak to moderate, indicating that cognitive functioning measured by the RFFT does not measure the same components of cognitive functioning as six subtasks of the CogState. Computerized testing such as the CogState may be very well suited for large cohort studies to assess cognitive functioning in the general population and to identify cognitive changes as early as possible, as it is a less time- and labor intensive tool.

No Effect of the Thr92Ala Polymorphism of Deiodinase-2 on Thyroid Hormone Parameters, Health-Related Quality of Life, and Cognitive Functioning in a Large Population-Based Cohort Study

INTRODUCTION

The presence of the Thr92Ala polymorphism of deiodinase-2 (D2) has been thought to have several effects. It may influence its enzymatic function, is associated with increased expression of genes involved in oxidative stress in brain tissue, and may predict favorable response to combination levothyroxine (LT4) plus triiodothyronine (T3) therapy. It was hypothesized that homozygous carriers of the D2-92Ala allele have different thyroid hormone parameters, and reduced health-related quality of life (HRQoL) and cognitive functioning.

METHODS

In 12,625 participants from the LifeLines cohort study with genome-wide genetic data available, the effects of the Thr92Ala polymorphism (rs225014) were evaluated in the general population and in 364 people treated with thyroid hormone replacement therapy, the latter mainly because of primary hypothyroidism. In addition to evaluating anthropometric data, medication use, and existence of metabolic syndrome, HRQoL was assessed with the RAND 36-Item Health Survey, and the Ruff Figural Fluency Test was used as a sensitive test for executive functioning. Data on thyrotropin, free thyroxine (fT4), and free T3 (fT3) levels were available in a subset of 4479 participants.

RESULTS

The mean age (±standard deviation) was 53 ± 12 years and the body mass index was 27.0 ± 4.5 kg/m2 in the LT4 users compared with 48 ± 11 years and 26.2 ± 4.1 kg/m2 in participants from the general population. The Ala/Ala genotype of the D2-Thr92Ala polymorphism was present in 11.3% of LT4 users and in 10.7% of the general population. In total, 3742/4479 subjects with thyroid hormone data available had normal TSH (0.4-4.0 mIU/L), and 88% of LT4 users were females. LT4 users had higher fT4, lower fT3, and a lower fT3/fT4 ratio, and female patients had lower scores on the HRQoL domains of physical functioning, vitality, mental health, social functioning, bodily pain, and general health compared with those not using LT4 (p < 0.005). Executive functioning scores, as part of cognitive functioning, were comparable between female LT4 users and the general population. In both groups, the D2-Thr92Ala polymorphism was not associated with differences in TSH, fT4, fT3, the fT3/fT4 ratio, presence of metabolic syndrome or other comorbidities, use of medication, HRQoL, and cognitive functioning.

CONCLUSION

The Thr92Ala polymorphism of D2 was not associated with thyroid parameters, HRQoL, and cognitive functioning in the general population and in participants on thyroid hormone replacement therapy.

A Computerized Test of Design Fluency

Tests of design fluency (DF) assess a participant’s ability to generate geometric patterns and are thought to measure executive functions involving the non-dominant frontal lobe. Here, we describe the properties of a rapidly administered computerized design-fluency (C-DF) test that measures response times, and is automatically scored. In Experiment 1, we found that the number of unique patterns produced over 90 s by 180 control participants (ages 18 to 82 years) correlated with age, education, and daily computer-use. Each line in the continuous 4-line patterns required approximately 1.0 s to draw. The rate of pattern production and the incidence of repeated patterns both increased over the 90 s test. Unique pattern z-scores (corrected for age and computer-use) correlated with the results of other neuropsychological tests performed on the same day. Experiment 2 analyzed C-DF test-retest reliability in 55 participants in three test sessions at weekly intervals and found high z-score intraclass correlation coefficients (ICC = 0.79). Z-scores in the first session did not differ significantly from those of Experiment 1, but performance improved significantly over repeated tests. Experiment 3 investigated the performance of Experiment 2 participants when instructed to simulate malingering. Z-scores were significantly reduced and pattern repetitions increased, but there was considerable overlap with the performance of the control population. Experiment 4 examined performance in veteran patients tested more than one year after traumatic brain injury (TBI). Patients with mild TBI performed within the normal range, but patients with severe TBI showed reduced z-scores. The C-DF test reliably measures visuospatial pattern generation ability and reveals performance deficits in patients with severe TBI.