Fractional anisotropy measurements of the left dorsolateral prefrontal cortex for therapeutic response assessment after repetitive transcranial magnetic stimulation (rTMS) in relapsing remitting multiple sclerosis patients suffering from depression

• Main Authors: Talaat A. Hassan, Shaima Fattouh Elkholy, Hatem S. Shehata, Nevin M. Shalaby, Alaa N. Elmazny, Mohamed N. Sadek, Bahaa Eldin Mahmoud, Mona M. Elsherbiny
• Format: Article
• Language: English
• Published: SpringerOpen 2021-01-01
• Series: The Egyptian Journal of Radiology and Nuclear Medicine
• Subjects: Multiple sclerosis; Depression; Cognition; rTMS; SSRIs; Diffusion tensor imaging
• Online Access: https://doi.org/10.1186/s43055-020-00404-x

Abstract Background Multiple sclerosis (MS) is a major cause of neurological disability in adults. Depression is one of the most common psychiatric comorbidities in MS patients with negative impact on patients’ quality of life. The aim of the study is to evaluate the role of diffusion tensor imaging (DTI) in monitoring the therapeutic response after high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) versus selective serotonin reuptake inhibitor (SSRI) therapy for relapsing remitting multiple sclerosis (RRMS) patients presenting with depression by measuring the factional anisotropy of the dorsolateral prefrontal cortex (DLPFC) before and after treatment and also to assess the treatments’ impact on patients’ cognitive functions and depression. Results Fractional anisotropy (FA) only increased in rTMS group (0.44 ± 0.03 pre-rTMS vs 0.53 ± 0.05 post-rTMS, P < 0.001), but there were no significant changes in the SSRI group (0.44 ± 0.04 pre-SSRIs vs 0.45 ± .37 post-SSRIs, P = 0.072). Both rTMS and SSRI groups showed significant clinical improvement in Beck Depression Inventory (BDI) and Paced Auditory Serial Addition Test (PASAT) after either intervention (17.6 ± 3.25 pre-rTMS vs 10.6 ± 1.89 post-rTMS and 23 ± 6.36 pre-rTMS vs 24.87 ± 6.6 post-rTMS, respectively, P < 0.001; 17.67 ± 3.15 pre-SSRIs vs 0.6 ± 1.84 post-SSRIs and 23.8 ± 6.45 pre-SSRIs vs 25.07 ± 7.02 post-SSRIs, respectively, P < 0.001). Conclusion DTI is an ideal non-invasive tool for examining white matter integrity and can detect microstructural changes in the dorsolateral prefrontal cortex after rTMS and SSRI therapies for patients with MS and depression. FA increased only with rTMS denoting positive alteration in white matter microstructure. Both rTMS and SSRIs were equally effective in improving depression and cognition.