Earley Christopher J, B Barker Peter, Horská Alena, Allen Richard P
Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA.
Sleep Med. 2006 Aug;7(5):458-61. doi: 10.1016/j.sleep.2005.11.009. Epub 2006 Jun 5.
Cerebrospinal fluid (CSF), magnetic resonance imaging (MRI) and autopsy studies have suggested that brain iron may be reduced in restless legs syndrome (RLS). Further analysis of the data also suggests that diminished brain iron may selectively be for early-onset RLS. This study was designed to replicate and extend our previous findings, specifically with regard to early-onset RLS. In this study our primary hypothesis was that substantia nigra (SN) iron index would be decreased in early-onset RLS compared to controls.
The iron concentration or 'iron index' in 10 brain regions was determined using MRI in 39 controls and in 22 early-onset and 19 late-onset RLS subjects. The Johns Hopkins RLS severity (JHRLSS) scale was used to define disease severity.
The mean iron index from the SN was significantly lower in the early-onset RLS compared to controls (t=2.5, P=0.016), while late-onset RLS and controls did not differ. There was a significant negative Spearman rank correlation between SN iron index and JHRLSS scale for the control-early-onset-RLS cohort (rho=-0.32, P=0.016).
The current MRI results in combination with previous autopsy data support the role of low brain iron in the SN in at least those with early-onset RLS symptoms.
脑脊液（CSF）、磁共振成像（MRI）及尸检研究表明，不安腿综合征（RLS）患者脑内铁含量可能降低。对数据的进一步分析还表明，脑内铁含量降低可能与早发型RLS有选择性关联。本研究旨在重复并扩展我们之前的发现，特别是关于早发型RLS的发现。在本研究中，我们的主要假设是，与对照组相比，早发型RLS患者黑质（SN）铁指数会降低。
采用MRI测定39名对照者、22名早发型RLS患者及19名晚发型RLS患者10个脑区的铁浓度或“铁指数”。使用约翰霍普金斯RLS严重程度（JHRLSS）量表来定义疾病严重程度。
与对照组相比，早发型RLS患者SN的平均铁指数显著降低（t = 2.5，P = 0.016），而晚发型RLS患者与对照组无差异。在对照 - 早发型 - RLS队列中，SN铁指数与JHRLSS量表之间存在显著的负斯皮尔曼等级相关性（rho = -0.32，P = 0.016）。
目前的MRI结果与先前的尸检数据相结合，支持至少在有早发型RLS症状的患者中，SN脑内铁含量低所起的作用。
