Microstructural Changes in the Striatum and Their Impact on Motor and Neuropsychological Performance in Patients with Multiple Sclerosis

Grey matter (GM) damage is a clinically relevant feature of multiple sclerosis (MS) that has been previously assessed with diffusion tensor imaging (DTI). Fractional anisotropy (FA) of the basal ganglia and thalamus might be increased in MS patients, and correlates with disability scores. Despite the established role of the striatum and thalamus in motor control, mood and cognition, the impact of DTI changes within these structures on motor and neuropsychological performance has not yet been specifically addressed in MS. We investigated DTI metrics of deep GM nuclei and their potential association with mobility and neuropsychological function. DTI metrics from 3T MRI were assessed in the caudate, putamen, and thalamus of 30 MS patients and 10 controls. Sixteen of the patients underwent neuropsychological testing. FA of the caudate and putamen was higher in MS patients compared to controls. Caudate FA correlated with Expanded Disability Status Scale score, Ambulation Index, and severity of depressive symptomatology. Putamen and thalamus FA correlated with deficits in memory tests. In contrast, cerebral white matter (WM) lesion burden showed no significant correlation with any of the disability, mobility and psychometric parameters. Our findings support evidence of FA changes in the basal ganglia in MS patients, as well as deep GM involvement in disabling features of MS, including mobility and cognitive impairment. Deep GM FA appears to be a more sensitive correlate of disability than WM lesion burden.灰质（Grey matter, GM）损伤是多发性硬化（multiple sclerosis, MS）的临床相关特征，既往多通过扩散张量成像（diffusion tensor imaging, DTI）进行评估。多发性硬化患者的基底神经节与丘脑各向异性分数（Fractional anisotropy, FA）可能升高，且与残疾评分存在相关性。尽管纹状体与丘脑在运动控制、情绪调节及认知功能中的作用已获证实，但上述结构内的DTI改变对多发性硬化患者运动与神经心理功能的影响，尚未在该疾病研究中得到专门探讨。本研究针对深部灰质核团的DTI指标及其与运动功能、神经心理功能的潜在关联展开了探究。我们对30名多发性硬化患者与10名健康对照受试者的尾状核、壳核及丘脑的3T MRI DTI指标进行了分析，其中16名患者完成了神经心理测试。相较于对照组，多发性硬化患者的尾状核与壳核FA值更高。尾状核FA值与扩展残疾状态量表（Expanded Disability Status Scale）评分、行走指数及抑郁症状严重程度呈显著相关；壳核与丘脑FA值则与记忆测试中的认知缺损存在关联。与之相反，脑白质（cerebral white matter, WM）病灶负荷与所有残疾、运动功能及心理测量参数均无显著相关性。本研究结果进一步证实了多发性硬化患者基底神经节FA值存在异常改变，且深部灰质受累与多发性硬化的致残性特征（包括运动功能障碍与认知损害）密切相关。深部灰质FA值似乎比脑白质病灶负荷更能敏感地反映残疾程度。