TY - JOUR
T1 - The verbal fluency index
T2 - Dutch normative data for cognitive testing in ALS
AU - Beeldman, Emma
AU - Jaeger, Bregje
AU - Raaphorst, Joost
AU - Seelen, Meinie
AU - Veldink, Jan
AU - Van Den Berg, Leonard
AU - De Visser, Marianne
AU - Schmand, Ben
PY - 2014/9
Y1 - 2014/9
N2 - Objective: Executive dysfunction occurs in 30-50% of amyotrophic lateral sclerosis (ALS) patients and is most frequently assessed with the verbal fluency test. The verbal fluency index (VFI) has been developed to correct for slowness of speech in ALS, and reflects the average thinking time per word. However, its use as a marker of cognitive impairment is hindered by the absence of valid norm scores. Therefore, we provide normative data for the VFI. Methods: Dutch volunteers were demographically matched to the Dutch ALS population and completed the verbal fluency index (one-minute and three-minute spoken letter fluency). Multiple stepwise linear regression was performed to assess the influence of demographic variables, past medical history and medication use. Results: 273 volunteers participated in this study. Educational level was negatively correlated to one-minute and three-minute VFI performance (r = -0.3 and r = -0.4, p < 0.001, respectively). No correlations for age, gender, medication and past medical history were found. A formula for standardized z-scores, corrected for educational level, for the one-minute and three-minute VFI was calculated. Conclusions: We provide Dutch normative data for the spoken verbal fluency index, which can be used internationally, but validation in other languages is recommended. The findings illustrate the importance of valid disease-specific norm scores for time-dependent cognitive tests in ALS.
AB - Objective: Executive dysfunction occurs in 30-50% of amyotrophic lateral sclerosis (ALS) patients and is most frequently assessed with the verbal fluency test. The verbal fluency index (VFI) has been developed to correct for slowness of speech in ALS, and reflects the average thinking time per word. However, its use as a marker of cognitive impairment is hindered by the absence of valid norm scores. Therefore, we provide normative data for the VFI. Methods: Dutch volunteers were demographically matched to the Dutch ALS population and completed the verbal fluency index (one-minute and three-minute spoken letter fluency). Multiple stepwise linear regression was performed to assess the influence of demographic variables, past medical history and medication use. Results: 273 volunteers participated in this study. Educational level was negatively correlated to one-minute and three-minute VFI performance (r = -0.3 and r = -0.4, p < 0.001, respectively). No correlations for age, gender, medication and past medical history were found. A formula for standardized z-scores, corrected for educational level, for the one-minute and three-minute VFI was calculated. Conclusions: We provide Dutch normative data for the spoken verbal fluency index, which can be used internationally, but validation in other languages is recommended. The findings illustrate the importance of valid disease-specific norm scores for time-dependent cognitive tests in ALS.
KW - Fluency
KW - Normative data
KW - Verbal fluency index (VFI)
UR - http://www.scopus.com/inward/record.url?scp=84906348753&partnerID=8YFLogxK
U2 - https://doi.org/10.3109/21678421.2014.906620
DO - https://doi.org/10.3109/21678421.2014.906620
M3 - Article
C2 - 24862654
SN - 2167-8421
VL - 15
SP - 388
EP - 391
JO - Amyotrophic lateral sclerosis and frontotemporal degeneration
JF - Amyotrophic lateral sclerosis and frontotemporal degeneration
IS - 5-6
ER -