en Neurology Neurology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> Thalamic atrophy may be an indicator of neurodegeneration in people with secondary progressive multiple sclerosis (pwSPMS). The atrophy usually begins asymmetrically, and the thalamic asymmetry index (TAI) can be used to estimate the severity of neurodegeneration. SPMS is commonly divided into two groups of active and inactive. No study has compared TAI between SPMS groups and examine its relationships with cognitive and motor measures in pwSPMS. This study aimed to compare the TAI between active and inactive pwSPMS and to examine its relationship with key clinical, cognitive, and motor variables.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> In this cross-sectional study, 38 pwSPMS (15 active and 23 inactive) were enrolled from February to November 2024. MRI-based volumetric measurements were used to determine thalamic volumes and calculate the TAI. Cognitive and motor tests, including the SDMT, PASAT, and 9HPT were also administered alongside clinical examinations.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> Active SPMS patients had significantly lower NTV compared to inactive patients (Cohen&rsquo;s d = -1.58, p < 0.001). No significant difference in TAI was observed between groups. NTV correlated with cognitive scores in both active (r = 0.74, P = 0.002) and inactive (r = 0.65, p < 0.001) groups and with disability in the inactive group (r = -0.5, P= 0.014). Active SPMS patients showed worse cognitive and motor performance.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> Thalamic atrophy is more severe in active SPMS and is associated with worse cognitive and motor outcomes. While thalamic asymmetry did not differentiate between subgroups, it may serve as a marker for functional status in SPMS.</span></span></span><br> &nbsp; Multiple sclerosis, SPMS, Thalamic atrophy, Cognitive performance, MRI, Neurodegeneration 595 602 http://caspjim.com/browse.php?a_code=A-10-3863-1&slc_lang=en&sid=1 Shadi Bahrami shadibahrami72@gmail.com 100319475328460057851 0009-0000-5196-5142 No Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Neda Ramezani n_ramezani227@yahoo.com 100319475328460057852 100319475328460057852 No Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Mohammad Yazdanpanah mohamad.yazdanpanahh@gmail.com 100319475328460057853 100319475328460057853 No Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Saeed Vaheb saeedvaheb.sv@gmail.com 100319475328460057854 100319475328460057854 No Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Omid Mirmosayyeb omid.mirmosayyeb@gmail.com 100319475328460057855 100319475328460057855 No Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Fariba Davanian f.davanian@med.mui.ac.ir 100319475328460057856 100319475328460057856 No Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Sahand Golparvar sahandgolparvar@gmail.com 100319475328460057857 100319475328460057857 No Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Iman adibi I.adibi@gmail.com 100319475328460057858 100319475328460057858 No Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Vahid Shaygannejad v.shaygannejad@gmail.com 100319475328460057859 0009-0008-6960-1265 Yes Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran