Brain-derived neurotrophic factor gene polymorphism differentially affects speech and language performance and recovery after stroke

Background: Stroke is the leading cause of long-term disability worldwide, with detrimental effects on many brain functions, such as speech and language. Data regarding the role of genetics in stroke recovery is lacking. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that was shown to be involved in stroke recovery. A single nucleotide polymorphism (SNP) in the BDNF gene was shown to affect its release and function. Data regarding the effect of this SNP on speech and language recovery after stroke is still lacking. Objective: This study assesses the role of BDNF gene polymorphism in speech and language performance and response to rehabilitation after stroke. Methods: patients with speech and language deficits referred to the speech and language rehabilitation clinic at King Abdullah University Hospital were recruited. A baseline speech and language assessment was performed, followed by a rehabilitation program. Additionally, a blood sample was obtained for BDNF genotyping. Results: Thirty-two patients participated in this study, with 12 patients (37.5 %) having the metBDNF genotype. Patients with metBDNF genotype had significantly lower speech performance at baseline (23.3 Vs. 8.5; p = 0.022) and lower response to the rehabilitation program (31.4 Vs. 39.1, p = 0.032). Furthermore, the BDNF genotype was identified as an independent predictor of baseline speech performance. Language baseline performance and response to rehabilitation were not affected by the BDNF genotype. Conclusion: The results indicate a differential effect of BDNF genotype on speech performance and recovery after stroke.