Department of Materials Process Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8601, Japan.
Department of Psychiatry, Shiga University of Medical Science, Seta Tsukinowa-Cho, Otsu, Shiga, 520-2192, Japan.
BMC Neurol. 2024 Sep 4;24(1):317. doi: 10.1186/s12883-024-03822-w.
Isolated rapid eye movement sleep behavior disorder (iRBD) serves as a prodromal phase of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Blunted tachycardia (BT) during postural changes indicates neurogenic orthostatic hypotension, a marker of autonomic dysfunction. We aimed to investigate whether BT is associated with cardiac sympathetic neurogenic denervation. Additionally, we conducted a preliminary short-term follow-up to examine the potential prognostic significance of BT regarding phenoconversion and mortality.
Forty-three patients with iRBD at Shiga University of Medical Science Hospital underwent active standing tests to identify BT, defined by a specific ratio of decrease in systolic blood pressure to inadequate increase in heart rate after standing, and orthostatic hypotension. I-metaiodobenzylguanidine myocardial scintigraphy (I-MIBG) and dopamine transporter single-photon emission computed tomography (DAT-SPECT) were performed. Participants were followed up for 3.4 ± 2.4 years for phenoconversion and 4.0 ± 2.3 years for mortality assessment, and the risk of events was analyzed using log-rank tests.
Among the 43 participants (mean age, 72.3 ± 7.9 years; 8 female), 17 met the BT criteria. We found no significant comorbidity-related differences in hypertension or diabetes between the BT(+) and BT(-) groups. Orthostatic hypotension was more prevalent in the BT(+) group than in the BT(-) group (47.1% vs 7.7%, p = 0.003). BT(+) patients were older with a lower early and delayed MIBG uptake; however, no significant differences were observed in DAT accumulation. Phenoconversion was observed in seven (41.2%) BT(+) and seven (26.9%) BT(-) patients. Three deaths were recorded in the BT(+) group (17.6%) and three in the BT(-) group (11.5%). No significant differences were observed in the risk of phenoconversion or mortality between the groups.
We have identified the possibility that BT reflects cardiac sympathetic neurogenic denervation in patients with iRBD. Future research is needed to elucidate the potential prognostic value of BT.
孤立性快速眼动睡眠行为障碍（iRBD）是帕金森病（PD）和路易体痴呆（DLB）的前驱期。直立位变化时心动过缓（BT）提示神经源性直立性低血压，是自主神经功能障碍的标志物。我们旨在研究 BT 是否与心脏交感神经去神经支配有关。此外，我们进行了初步的短期随访，以研究 BT 对表型转化和死亡率的潜在预后意义。
在滋贺医科大学医院的 43 名 iRBD 患者进行了主动站立测试以确定 BT，BT 定义为站立后收缩压下降与心率增加不足的特定比值，并确定直立性低血压。进行碘-间位碘苄胍心肌闪烁照相术（I-MIBG）和多巴胺转运蛋白单光子发射计算机断层扫描（DAT-SPECT）。对参与者进行了 3.4±2.4 年的表型转化和 4.0±2.3 年的死亡率评估，使用对数秩检验分析事件风险。
在 43 名参与者（平均年龄 72.3±7.9 岁；8 名女性）中，17 名符合 BT 标准。我们发现 BT(+)和 BT(-)组在高血压或糖尿病等合并症方面无显著差异。BT(+)组比 BT(-)组更常见直立性低血压（47.1%比 7.7%，p=0.003）。BT(+)患者年龄较大，早期和延迟 MIBG 摄取较低；然而，DAT 积聚没有明显差异。BT(+)组有 7 例（41.2%）和 BT(-)组有 7 例（26.9%）发生表型转化。BT(+)组有 3 人死亡（17.6%），BT(-)组有 3 人死亡（11.5%）。两组在表型转化或死亡率的风险方面无显著差异。
我们已经确定 BT 可能反映 iRBD 患者的心脏交感神经去神经支配。需要进一步研究来阐明 BT 的潜在预后价值。
