REM sleep without atonia thresholds are associated with reduced cardiac MIBG uptake but not with DAT-SPECT…

Cohort studySleep medicine· Nov 2026

REM sleep without atonia thresholds are associated with reduced cardiac MIBG uptake but not with DAT-SPECT binding in probable REM sleep behavior.

Izumi Mihashi, Yoichiro Takei, Fusae Kawana … Shinji Saiki

Nuclear MedicineCohort studyDiagnosisQ1IF 3.8

RWA thresholds strongly linked to reduced cardiac MIBG uptake in probable REM sleep behavior disorder

REM sleep without atonia thresholds are associated with reduced cardiac MIBG uptake but not with DAT-SPECT binding in probable REM sleep behavior.

Izumi Mihashi … Shinji Saiki

Sleep medicine · Nov 2026 · Q1 in General Medicine

Background

Quantitative thresholds for REM sleep without atonia (RWA) vary across populations, and their relationships with neuroimaging markers of Lewy body disease remain incompletely understood.

Purpose

To examine whether previously proposed RWA thresholds for Japanese patients are associated with cardiac sympathetic and striatal dopaminergic imaging markers.

Methods

This multicenter study included 91 Japanese patients with probable RBD (isolated or PD-associated).

n = 91 Japanese patients

97.8%

Results

97.8%

nearly all with elevated RWA showed reduced cardiac sympathetic uptake

n = 91 Japanese patients

More results

No significant correlation existed between the specific binding ratio (specific binding ratio) and either %RWA or MDS-UPDRS-III scores.

Notably, RWA and RBDQ-JP scores were only weakly correlated (r s = 0.14-0.37); among patients exceeding the RWA threshold, 19.7% scored below the RBDQ-JP cutoff of 19.5.

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Conclusion · 1 of 2

The Japanese Sleep Innsbruck Barcelona and AASM phasic RWA thresholds are strongly associated with reduced cardiac MIBG uptake, but not with striatal dopamine transporter binding.

Conclusion · 2 of 2

These findings support an association between elevated RWA and cardiac sympathetic denervation, while suggesting that optimal thresholds vary across populations.

REM sleep without atonia thresholds are associated with reduced cardiac MIBG uptake but not with DAT-SPECT binding in probable REM sleep behavior.

REM sleep without atonia thresholds are associated with reduced cardiac MIBG uptake but not with DAT-SPECT binding in probable REM sleep behavior.

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