Preclinical substantia nigra dysfunction in rapid eye movement sleep behaviour disorder

Objectives

Transcranial sonography (TCS) has been shown to reveal hyperechogenicity of the substantia nigra (SN) in people with Parkinson’s disease and in approximately 10% of healthy subjects. It is hypothesized that SN hyperechogenicity in healthy subjects and patients with idiopathic rapid eye movement (REM) sleep behaviour disorder (iRBD) patients is a marker of vulnerability for Parkinson’s disease.

Methods

TCS and positron emission tomography (PET) with 6-[¹⁸F] fluoro-meta-tyrosine (FMT), which can assess the level of the presynaptic dopaminergic nerve, were performed in 19 male patients with iRBD, mean age 66.4 (standard deviation [SD] 4.9) years, to assess nigrostriatal function.

Results

Nine patients had pathological SN hyperechogenicity (mean age 66.8 [SD 3.9] years; 0.31 [SD 0.12] cm²) and 10 patients did not have SN hyperechogenicity (mean age 66.0 [SD 5.8] years; 0.11 [SD 0.06] cm²). FMT uptake at the putamen and caudate was significantly lower in iRBD patients with pathological SN hyperechogenicity compared with those without SN hyperechogenicity. However, no correlation was found between SN echogenicity and FMT uptake. This is in conflict with previous findings which showed that subjects with hyperechogenicity had lower FMT uptake in the striatum.

Conclusion

Pathological hyperechogenic alterations in the SN in patients with iRBD may suggest the existence of preclinical SN dysfunction as determined by FMT-PET.     

特发性快速眼动睡眠期行为障碍经颅脑实质超声研究

目的探讨快速眼动睡眠期行为障碍患者经颅脑实质超声改变。方法符合睡眠障碍国际分类第2版快速眼动睡眠期行为障碍诊断标准的15例患者(RBD组)和15例正常对照受试者,于多导睡眠图监测后通过经颅脑实质超声检查并测量中脑黑质高回声、基底节高回声、第三脑室宽度;简易智能状态检查量表(MMSE)和蒙特利尔认知评价量表(MoCA)评价认知功能。结果快速眼动睡眠期行为障碍患者具有典型的临床表现和电生理学改变。RBD组黑质高回声(6/15)、基底节高回声(7/15)阳性检出率,与正常对照组(1/15和2/15)之间差异无统计学意义(P=0.080,0.109)。RBD组伴与不伴黑质高回声患者MoCA评分差异无统计学意义(P=0.075);但RBD组伴基底节高回声患者MMSE评分高于不伴基底节高回声患者(P=0.021)。结论快速眼动睡眠期行为障碍作为突触共核蛋白病前驱期,经颅脑实质超声可表现为黑质和基底节高回声,且伴不同结局。经颅脑实质超声可以检测出脑亚临床改变,评价突触共核蛋白病风险。     

快速眼动睡眠期行为障碍患者运动和认知功能障碍及脑功能连接研究

目的探讨快速眼动睡眠期行为障碍(RBD)患者运动和认知功能障碍以及黑质与各脑区的功能连接。方法共14例快速眼动睡眠期行为障碍患者和8例性别、年龄、受教育程度相匹配的正常对照者,采用统一帕金森病评价量表第三部分(UPDRSⅢ)和Hoehn-Yahr分期评价运动功能,数字排序测验之注意力部分、符号数字模式测验(SDMT)、Stroop色词测验、连线测验(TMT)、Rey-Osterrieth复杂图形测验(ROCFT)、画钟测验、Boston命名测验和听觉词语学习测验(AVLT)评价认知功能,静息态f MRI观察左侧和右侧黑质与各脑区的功能连接。结果两组受试者UPDRSⅢ评分和Hoehn-Yahr分期差异无统计学意义(均P0.05);RBD组患者SDMT评分(P=0.001)、ROCFT量表之临摹部分评分(P=0.013)和AVLT量表之第2次瞬时回忆部分评分(P=0.032)低于正常对照组,TMT-B测试部分评分高于正常对照组(P=0.005)。与正常对照组相比,RBD组患者右侧黑质与左侧中央前回(P0.005)和右侧角回(P0.005)的功能连接下降。结论快速眼动睡眠期行为障碍患者认知功能障碍早于运动障碍,且黑质与运动功能区和认知功能区均存在异常功能连接,为快速眼动睡眠期行为障碍患者的行为学改变提供脑功能连接异常的客观证据。     

特发性快速眼动睡眠期行为障碍纹状体微结构磁共振成像研究

目的探讨帕金森病(PD)和特发性快速眼动睡眠期行为障碍(iRBD)患者纹状体结构和白质纤维束完整性。方法联合应用基于体素的形态学分析和扩散张量成像对12例特发性快速眼动睡眠期行为障碍患者、12例帕金森病患者及10例性别、年龄和受教育程度相匹配的正常对照者进行头部MRI检查,观察纹状体结构(灰质体积)和白质纤维束完整性[部分各向异性(FA)值]变化。结果与对照组相比,iRBD组左侧尾状核灰质体积缩小(P0.005),以及左侧(P0.005)和右侧(P0.001)尾状核、右侧壳核(P0.05)FA值降低;PD组仅右侧壳核FA值降低(P0.05)。与PD组相比,iRBD组左侧尾状核灰质体积缩小(P0.001),以及左侧(P0.01)和右侧(P0.005)尾状核FA值降低。结论特发性快速眼动睡眠期行为障碍患者存在纹状体灰质体积缩小和白质纤维束完整性损害,其白质纤维束完整性损害与帕金森病具有一致性,为特发性快速眼动睡眠期行为障碍是帕金森病的临床前期提供解剖学依据。     

Investigating rapid eye movement sleep without atonia in Parkinson's disease using the rapid eye movement sleep behavior disorder screening questionnaire

Rapid eye movement (REM) sleep behavior disorder (RBD) is frequently observed in patients with Parkinson's disease (PD). Accurate diagnosis is essential for managing this condition. Furthermore, the emergence of idiopathic RBD in later life can represent a premotor feature, heralding the development of PD. Reliable, accurate methods for identifying RBD may offer a window for early intervention. This study sought to identify whether the RBD screening questionnaire (RBDSQ) and three questionnaires focused on dream enactment were able to correctly identify patients with REM without atonia (RWA), the neurophysiological hallmark of RBD. Forty‐six patients with PD underwent neurological and sleep assessment in addition to completing the RBDSQ, the RBD single question (RBD1Q), and the Mayo Sleep Questionnaire (MSQ). The REM atonia index was derived for all participants as an objective measure of RWA. Patients identified to be RBD positive on the RBDSQ did not show increased RWA on polysomnography (80% sensitivity and 55% specificity). However, patients positive for RBD on questionnaires specific to dream enactment correctly identified higher degrees of RWA and improved the diagnostic accuracy of these questionnaires. This study suggests that the RBDSQ does not accurately identify RWA, essential for diagnosing RBD in PD. Furthermore, the results suggest that self‐report measures of RBD need to focus questions on dream enactment behavior to better identify RWA and RBD. Further studies are needed to develop accurate determination and quantification of RWA in RBD to improve management of patients with PD in the future. © 2014 International Parkinson and Movement Disorder Society     

特发性快速眼球运动睡眠行为障碍患者认知脑区灰质体积的改变

目的 通过对特发性快速眼球运动睡眠行为障碍(iRBD)患者认知脑区改变的探索,寻找其与帕金森病(PD)患者大脑形态改变的异同,为两者的联系提供依据.方法 对14例iRBD患者、12例PD患者及8名健康人(CON组)进行认知心理测评(复杂图形测试、临摹及回忆、符号-数字转换测试、连线测试、画钟测试、数字广度测验)及磁共振检查,采用基于体素形态学的研究技术进行分析.结果 iRBD组及PD组患者的数字符号转换测试、连线测验测试2与CON组之间的差异均有统计学意义(P<0.05),iRBD组与PD组间的差异无统计学意义(P>0.05);与CON组比较,iRBD组与PD组患者的右顶叶及左枕叶体积均缩小(P<0.05),但iRBD组与PD组间的差异无统计学意义(P>0.05);PD组右枕叶较CON组体积减小(P<0.05).结论 iRBD患者及PD患者均出现注意力及执行功能等认知能力下降,并且都出现右顶叶和枕叶萎缩,提示两者的认知损害存在相似的病理基础.     

早期帕金森病患者快速眼动睡眠期行为障碍研究

目的探讨早期帕金森病患者快速眼动睡眠期行为障碍发生情况,以及帕金森病运动症状、非运动症状和快速眼动睡眠期行为障碍特点。方法共60例原发性帕金森病患者,采用统一帕金森病评价量表第二和第三部分(UPDRSⅡ和UPDRSⅢ)以及Hoehn-Yahr分期评价帕金森病非运动症状和运动症状,蒙特利尔认知评价量表评价认知功能,汉密尔顿焦虑量表和汉密尔顿抑郁量表评价焦虑和抑郁症状;中文版快速眼动睡眠期行为障碍筛查量表判断是否伴快速眼动睡眠期行为障碍,Epworth嗜睡量表(ESS)评价白天过度嗜睡程度;多导睡眠图监测睡眠障碍特征,包括下颌位相性肌电活动密度和快速眼动睡眠期肌肉失弛缓。结果 60例帕金森病患者中42例(70%)伴快速眼动睡眠期行为障碍(PD+RBD组),多导睡眠图监测其异常行为主要表现为上肢伸展抓握、肢体震颤抽搐、发笑、喊叫和怒骂等非暴力动作,仅2例出现暴力击打、蹬踢等异常行为。PD+RBD组患者年龄(P=0.024)、病程8年比例(P=0.000)、UPDRSⅡ(P=0.005)和UPDRSⅢ(P=0.001)评分、Hoehn-Yahr分期2级比例(P=0.007)、焦虑障碍(P=0.044)和抑郁障碍(P=0.001)比例,以及下颌位相性肌电活动密度(P=0.000)和快速眼动睡眠期肌肉失弛缓比例(P=0.000)均高于对照组,其中,PD+RBD组有16例(38.10%)快速眼动睡眠期行为障碍症状早于帕金森样症状5.20(3.91,6.51)年。结论年龄大、病程长、运动症状和非运动症状严重的帕金森病患者易伴发快速眼动睡眠期行为障碍,快速眼动睡眠期行为障碍可能是帕金森病的早期表现。多导睡眠图监测对早期帕金森病伴快速眼动睡眠期行为障碍的诊断有重要参考价值。     

帕金森病合并快速眼球运动睡眠行为障碍患者的客观睡眠结构及认知功能

目的 评价帕金森病合并快速眼球运动睡眠行为障碍(RBD)患者的睡眠结构及认知功能,并探讨其睡眠结构与认知功能之间的相关性.方法 本研究为横断面研究,以在我院睡眠中心进行睡眠监测的39例帕金森病合并RBD患者作为病例组,并以年龄、性别相匹配的21例原发性快速眼球运动睡眠行为障碍(iRBD)患者及37例不合并RBD的帕金森病患者作为对照组.所有患者均行整夜睡眠监测以定量睡眠相关参数,并且于监测当天使用蒙特利尔(MoCA)评估量表评估其认知功能.采用多重线性回归分析量表得分与睡眠结构之间的相关性.结果 (1)帕金森病合并RBD患者的睡眠效率(60.9％±16.9％)、总睡眠时间[(329.7±96.5)min]、非快速眼动睡眠2期时间[(127.6±67.6) min]及快速眼动睡眠期时间[(45.3 ±33.2) min]较iRBD组的相应值[77.8％±16.9％以及(397.1 ±88.9)、(188.0±94.7)、(70.6 ±25.9) min]比较明显减少(均P＜0.05),较不合并RBD的PD组的相应值[61.3％±21.7％以及(324.9 ±134.6)、(132.6 ±65.6)、(47.1±31.9)min]减少,但差异均无统计学意义.3组的睡眠潜伏期、快速眼球运动睡眠潜伏期、非快速眼球运动睡眠1期,慢波睡眠比例、氧减指数、呼吸暂停低通气指数及周期性肢体运动指数比较差异均无统计学意义.(2)帕金森病合并RBD患者认知功能最差,其中视空间与执行功能得分[(3.8±1.1)分]较iRBD组[(4.4±0.7)分]比较差异有统计学意义(F=3.426,P＜0.05).(3)多重线性回归显示帕金森病合并RBD患者的RBD病程、睡眠效率和非快速眼动睡眠2期与视空间与执行功能得分有相关性.结论 帕金森病合并RBD患者的睡眠效率、总睡眠、非快速眼动睡眠2期及快速眼动睡眠期时间和认知功能均明显下降,认知功能的改变与睡眠结构的变化可能存在相关性.     

Difference in severity of sleep apnea in patients with rapid eye movement sleep behavior disorder with or without parkinsonism

ObjectiveRapid eye movement sleep behavior disorder (RBD) is a common sleep disturbance in patients with neurodegenerative disorders. We aimed to compare sleep parameters among the different types of RBD patients.MethodsA total of 122 patients with dream enactment behavior were screened. Of these, 92 patients who were diagnosed with RBD by polysomnography were included in this study. Enrolled patients with RBD were classified into four groups based on the following diagnoses: idiopathic RBD (iRBD); RBD with Parkinson disease (PD-RBD); multiple system atrophy (MSA) with RBD (MSA-RBD); and dementia with Lewy bodies (DLB) with RBD (DLB-RBD). Various clinical and polysomnographic parameters were compared.ResultsAmong the 92 patients with RBD, 35 had iRBD, 25 had PD-RBD, 17 had MSA-RBD, and 15 had DLB-RBD. The mean apnea−hypopnea index of atypical parkinsonism with RBD (AP-RBD) group was 16.2 ± 17.7 events/h (MSA-RBD, 14.0 ± 16.6; DLB-RBD, 18.8 ± 19.1), which was significantly higher than the other groups (p < 0.05). The proportion of patients with 100% supine sleep in the AP-RBD group (44%) was higher than that in the iRBD group (14%; p = 0.030). The proportion of OSA with 100% supine sleep position was significantly higher in the MSA-RBD and DLB-RBD groups than in the iRBD group (p = 0.042 and p = 0.029, respectively).ConclusionOur study demonstrated that patients in the MSA-RBD and DLB-RBD groups had a tendency to sleeping in the supine position and a higher vulnerability to OSA compared to other RBD groups. Further cohort studies are needed to evaluate the influence of these factors on the development of parkinsonism.     

伴快速眼球运动睡眠行为障碍的帕金森病患者临床特征

目的 评价快速眼球运动睡眠行为障碍(RBD)在帕金森病(PD)患者中的患病率以及伴发RBD的PD患者临床特征.方法 2007年连续入组124例PD患者,采用非运动症状问卷(NMSquest)第25项问答结果调查PD患者中RBD患病率;将入选患者分为RBD组(78例)和非RBD组(13例),采用统一PD评分量表(UPDRS)、Hoehn-Yahr(H-Y)分级比较2组运动症状严重程度和运动并发症发生情况;选用NMSquest量表比较2组非运动症状发生情况,选用MMSE、汉密尔顿抑郁量表(HAMD)、汉密尔顿焦虑量表(HAMA)、帕金森病睡眠量表(PDSS)和Epworth嗜睡量表(ESS)比较2组认知功能、焦虑和抑郁、夜间睡眠障碍和日间思睡程度.结果 (1)RBD的患病率为62.9%(78/124);(2)RBD组患者的病程[(3.8±2.8)年]显著短于非RBD组[(5.0±2.5)年,t=-1.972,P=0.048],但在性别、年龄、起病年龄、发病类型、左旋多巴等效剂量(LDE)和用药种类上2组差异没有统计学意义;(3)在运动症状中RBD与非RBD组在H-Y分级、UPDRS-Ⅱ、Ⅲ、Ⅳ评分以及运动并发症发生率方面差异无统计学意义;(4)在非运动症状中胃肠道功能、自主神经系统功能、精神和睡眠活动等方面的不良症状在RBD组的发生率显著高于非RBD组,但是认知、焦虑和抑郁、夜间睡眠障碍和日间思睡的严重程度在2组间差异没有统计学意义.结论 RBD在PD患者中的患病率较高,伴发RBD的PD患者病程较短且非运动系统受累更加广泛.     

快速眼动睡眠期行为障碍与神经变性病发病机制研究进展

快速眼动睡眠期行为障碍系指快速眼动睡眠期肌肉失弛缓,并出现梦境(通常是暴力梦境)相关肢体运动(梦境演绎行为)。其人群发病率为0.38%~2.01%,在神经变性病尤其是α-突触核蛋白病患者中的发病率明显增加。快速眼动睡眠期行为障碍可早于α-突触核蛋白病数十年出现,因此可以作为预测神经变性病的早期标记。本文拟就近年来关于快速眼动睡眠期行为障碍发病机制及其与神经变性病之间的关系进行简要综述。     

帕金森病患者快速眼球运动睡眠行为障碍的回顾分析及前瞻性研究

目的 临床回顾分析帕金森病(PD)患者快速眼球运动(REM)睡眠行为障碍(RBD)的发生率及其危险因素,前瞻性研究RBD对PD进展的影响.方法 根据国际睡眠障碍分型修订版(ICSD-R)关于RBD的最低诊断标准,对符合临床疑似RBD(cpRBD)的患者进行统一PD评估量表(UPDRS)、MMSE、蒙特利尔认知功能评估量表(MoCA)等测定与随访观察,随访时间为2.5年.结果 基线时cpRBD的发生率为35.6%(47/132),随访末的发生率为41.7%(55/132),脱落率为11.4%(15/132).RBD的独立危险因素为MoCA分值低(OR=0.817,P=0.004),而震颤型起病形式为RBD的保护因素(OR=0.247,P=0.020).cpRBD患者病情进展较非cpRBD患者快[UPDRSⅢ终点与基线差值:(9.86±4.96)分与(6.76±4.26)分,t=2.909,P=0.005;H-Y分期终点与基线差值:(0.77±0.54)期与(0.33±0.49)期,t=3.664,P=0.000].结论 RBD的发生可能预测PD病情的快速进展、认知功能损害、精神症状的出现.     

Increased neural motor activation and functional reorganization in patients with idiopathic rapid eye movement sleep behavior disorder

IntroductionAltered brain activity and functional reorganization patterns during self-initiated movements have been reported in early pre-motor and motor stages of Parkinson's disease. The aim of this study was to investigate whether similar alterations can be observed in patients with idiopathic REM-sleep behavior disorder (RBD).Methods13 polysomnography-confirmed male and right-handed RBD patients and 13 healthy controls underwent a bilateral hand-movement fMRI task including internally selected (INT) and externally-guided (EXT) movement conditions for each hand. We examined functional activity and connectivity differences between groups and task-conditions, structural differences using voxel-based morphometry, as well as associations between functional activity and clinical variables.ResultsNo group differences were observed in fMRI-task performance or in voxel-based morphometry. Both groups showed faster reaction times and exhibited greater neural activation when movements were internally selected compared to externally-guided tasks. Compared to controls, RBD patients displayed stronger activation in the dorsolateral prefrontal cortex and primary somatosensory cortex during INT-tasks, and in the right fronto-insular cortex during EXT-tasks performed with the non-dominant hand. Stronger activation in RBD patients was associated with cognitive and olfactory impairment. Connectivity analysis demonstrated overall less interregional coupling in patients compared to controls. In particular, patients showed reduced temporo-cerebellar, occipito-cerebellar and intra-cerebellar connectivity, but stronger connectivity in fronto-cerebellar and fronto-occipital pathways.ConclusionThe observed stronger activation during hand-movement tasks and connectivity changes in RBD may reflect early compensatory and reorganization patterns in order to preserve motor functioning. Our findings may contribute to a better understanding and prognosis of prodromal stages of α-synucleinopathies.     

Neural substrates of rapid eye movement sleep behavior disorder in Parkinson's disease

ObjectivesTo investigate neural substrates of symptomatic rapid eye movement sleep behavior disorder (RBD) in Parkinson's disease (PD) by analyzing brain changes based on both hypothesis-free and hypothesis-driven neuroimaging analyses.MethodsA total of 63 subjects (14 PDRBD−, 24 PDRBD+, and 25 age-matched healthy controls = HC) were enrolled in this study. RBD was defined by RBD screening questionnaire with video-polysomnographic confirmation. All subjects underwent volumetric and diffusion tensor imaging. The whole brain gray- and white-matter changes were analyzed and the central ascending cholinergic pathway involving the pedunculopontine nucleus and thalamus was compared with a region-of-interest analysis and probabilistic tractography.ResultsThe PDRBD+ group showed decreased gray matter volume of the left posterior cingulate and hippocampus compared to the PDRBD− and additional gray matter decrease in the left precuneus, cuneus, medial frontal gyrus, postcentral gyrus and both inferior parietal lobule compared to the HC group (uncorrected p < 0.001, k = 50). There were no significant differences in white matter changes between the PDRBD− and PDRBD+ groups both by fractional anisotropy and mean diffusivities. However, both PD groups showed widespread changes by fractional anisotropy reductions and mean diffusivity increments compared to HC (p < 0.05 corrected). There were no significant differences in tract-based spatial statistics and the normalized tract volumes as well as the diffusion indices of both the thalamus and pedunculopontine nuclei among the study groups.ConclusionsThe appearance of RBD in PD may be related to regional gray matter changes in the left posterior cingulate and hippocampus but not localized to the brainstem.     

Relationship of substantia nigra hyperechogenicity to risk of Lewy body disease in idiopathic REM sleep behavior disorder patients: a longitudinal study

BackgroundWe examined the relationship between baseline substantia nigra (SN) echogenicity on transcranial sonography (TCS) images and medium-to long-term developments of Parkinson's disease (PD) and dementia with Lewy bodies (DLB) in idiopathic RBD (IRBD) patients.MethodsFrom 2007–2009, TCS and odor identification tests were performed in 34 consecutive IRBD patients (67.9 ± 6.1 years). A medical chart review was conducted in August 2019 to investigate the development of PD or DLB.ResultsOf the 34 IRBD patients, 14 (41.2%) showed SN hyperechogenicity (SN+) on TCS at baseline. There were no significant differences in age, Unified Parkinson's Disease Rating Scale (UPDRS) score, Mini-Mental State Exam (MMSE) score, or odor identification (OSIT-J) score between the SN+ and SN normoechogenicity (SN−) groups at baseline. The phenoconversion rate was 57.4% (n = 8) in the SN+ group (mean 5.8 years from baseline TCS), and 25.0% (n = 5) in the SN− group (mean 8.6 years from baseline TCS). Of those with phenoconversions, there were five PD patients and three DLB patients in the SN+ group, and one PD patient and four DLB patients in the SN− group. The SN+ group had a higher estimated risk for disease development than the SN− group. The coexistence of SN+ with functional anosmia may predict a short-term Lewy body disease onset risk.ConclusionA single baseline TCS for IRBD patients may be a suitable test for screening and predicting groups at high-risk for developing PD or DLB. This may help to select appropriate IRBD patients in clinical trials for disease modifying therapy to prevent progression to PD or DLB.     

Olfactory deficit in idiopathic rapid eye movements sleep behavior disorder

INTRODUCTION: REM sleep behavior disorder (RBD) is a parasomnia characterized by a loss of atonia and an increased phasic muscle activity during REM sleep. Idiopathic RBD frequently herald an alpha-synucleinopathy, including such as Parkinson's disease (PD) and dementia with Lewy Body (DLB). Pathological changes in the anterior olfactory nucleus and olfactory loss occur very early in the course of PD and DLB. The aim of the study was to assess olfactory function in a large group of idiopathic RBD patients. METHODS: Fifty-four consecutive polysomnographically-confirmed iRBD patients (44 men, 10 women; mean age: 69.2+/-8.3 years; mean Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) score: 4.9+/-4.3) and 54 age and gender-matched control subjects underwent the Brief University of Pennsylvania Smell Identification Test (B-SIT). RESULTS: A marked olfactory impairment was observed in the RBD group (mean B-SIT score: 7.1+/-2.5 versus 9.4+/-1.8; p < 0.0001), with 33 (61.1%) RBD patients versus 9 (16.6%) controls showing abnormal olfactory function (p < 0.0001). No correlation was found between the degree of olfactory loss and either duration of RBD symptoms or UPDRS-III score. Deficit in recognize paint thinner odorant showed the highest positive predictive value (0.95) for identifying idiopathic RBD. CONCLUSIONS: The olfactory deficit found in most idiopathic RBD patients shares similarities with that described in PD and may be a sign of a widespread neurodegenerative process. Its detection may help in identifying subjects at higher risk of developing an alpha-synucleinopathy-mediated neurodegeneration.     

Altered resting-state thalamo-occipital functional connectivity is associated with cognition in isolated rapid eye movement sleep behavior disorder

ObjectiveIsolated rapid eye movement sleep behavior disorder (iRBD) patients are at risk of cognitive impairments, however the underlying mechanism is still unclear. This study aimed to evaluate thalamo-cortical functional connectivity (FC) using resting-state functional magnetic resonance imaging (fMRI) and its correlation with cognitive dysfunction in patients with iRBD.MethodsA total 37 polysomnographies (PSGs) confirmed iRBD patients and 15 age-sex matched controls underwent resting-state fMRI and comprehensive neuropsychological assessment. Thalamo-cortical FC was evaluated by using seed-to voxel analysis and was compared between the iRBD and controls. Correlation between the average value of significant clusters and cognitive function scores in iRBD were calculated.ResultsCompared to the control subjects, patients with iRBD patients showed cognitive decline in word list recognition (p = 0.016), and constructional recall (p = 0.044). The FC analysis showed increased FC between the left thalamus and occipital regions including the right cuneal cortex, left fusiform gyrus and lingual gyrus (cluster level p < 0.05, corrected for false discovery rate). The averaged thalamo-fusiform FC value positively correlated with word list recognition after adjusting for age and sex (adjusted r = 0.347, p = 0.041).ConclusionThalamic resting state FC is altered in iRBD patients and is associated with the cognitive function. Enhancement of the thalamo-occipital FC may reflect a compensatory mechanism for cognitive impairment in iRBD.