Use of the Behavioral Dyscontrol Scale-2 (BDS-2) to measure executive dysfunction in FXTAS.

BACKGROUND/

OBJECTIVE

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a neurodegenerative disorder caused by a premutation (55 to 200 CGG repeats) in the FMR1 gene. This expansion leads to mRNA toxicity, resulting in the deterioration of executive and cognitive abilities alongside characteristic brain changes detected via Magnetic Resonance Imaging (MRI). While the Behavioral Dyscontrol Scale-2 (BDS-2) is commonly used to evaluate executive function, its specific relationship with neuroanatomical markers in FXTAS has not been fully examined. This study investigated the association between BDS-2 and MRI scores in FXTAS.

METHODS

Correlation and linear regression analyses were conducted to evaluate how BDS-2 scores correlate with MRI total scores and other neurodegeneration variables, measured by white matter hyperintensities, relative to the MMSE and CANTAB subtests in 56 FMR1 premutation carriers with and without FXTAS.

RESULTS

MRI scores were negatively correlated with BDS-2 total scores (Pearson's r = -0.66, p < 0.0001). The association between BDS-2 total scores and MRI scores was still significant after accounting for CGG repeat length, sex, and age as covariates (β = -0.36, p = 0.002). In the complete-case sample analysis (n = 30), the executive functioning subtests of the CANTAB were positively correlated with the MRI total score (ρ = 0.46-0.61, p < 0.05), while the MMSE demonstrated a negative correlation (ρ = -0.40, p = 0.03).

CONCLUSION

These findings indicate that BDS-2 can be used alongside other instruments for measuring executive dysfunction in FXTAS, demonstrating the potential for clinical utility to complement traditional cognitive and automated executive measures.