Letter to the Editor Involvement of cardiac sympathetic nerve endings in a patient with idiopathic RBD and intact nigrostriatal pathway q We describe a 72-year-old Italian woman with frequent night- time movement disorders. She was born from consanguineous parents, and she is currently married with three healthy sons. She was seen at our hospital because of a history of sleep disorder that began at the age of 69. She had a past history of hypertension that was very well controlled with drugs and she had a history of mild depression that was never treated with psychotropic medica- tions. She did not have history of epilepsy nor alcohol abuse. During sleep, the patient was noticed to have strong shaking of her limbs and episodes of laughing, talking and screaming; she would also frequently fall out of bed. The patient had noted a change in the nature of her dreams as they had become more vivid and disturbing, and she had started to experience frequent nocturnal nightmares. Moreover, on many occasions she would awaken several times during the night to find herself lying on the floor with bruises or lacerations on her body caused by falling out of bed. For three years these nocturnal episodes had occurred almost every night and mainly in the first part of sleep. She had no excessive daytime sleepiness. There was no familial history of neurological disorders. When she was first admitted to our clinic (May 2008), her neurological examination was normal. She underwent a large battery of cogni- tive tests (executive functions, short- and long-term verbal memory, visuo-constructive praxis, logical thinking, verbal fluency; Mini Mental State examination (MMSE)), blood tests, chest x-ray, electrocardiogram (ECG), echocardiography, holter blood pressure monitoring and brain magnetic resonance imaging (MRI). Electro- encephalograms (EEG) were recorded while the patient was awake and while asleep. A polysomnografic examination (PSG) was per- formed according to a standard clinical protocol with EEG record- ings (electrodes: Fp2, C4, O2, Fp1, C3, O1), electro-oculography, ECG, oronasal and thoracoabdominal airflow and electromyog- raphy (EMG) recorded from both mylohyoid and anterior tibial muscles. The patient was also observed with an infrared video to detect movements during REM sleep. The diagnosis of RBD was made according to the International Classification of Sleep Disor- ders [1]. Olfactory functions have not been investigated. All cogni- tive tests were normal and MMSE showed a score of 28/30 corrected (n.v.  24/30). The patient did not suffer of orthostatic hypotension. Brain imaging was normal. Few central sleep apnoeas were observed during stage II of non-REM sleep lasting between 10 and 20 s. PSG revealed several behavioural episodes with an elevated tonic and phasic muscle tone of the mylohyoid and ante- rior tibial muscles during the REM sleep stage (Fig. 1). There was no epileptiform activity throughout the recording. We have furthermore performed a cerebral single photon emis- sion computed tomography (DAT-SPECT scan) with 123 I-FP-CIT, which came back with normal results (Fig. 2 a); whereas, the myocardial 123 metaiodiobenzylguanidine (MIBG) scintigraphy showed a markedly reduced cardiac uptake (Fig. 2 b). A treatment with 0.75 mg per day of clonazepam was started. Here we describe, for the first time, a patient with idiopathic RBD and a marked decrease of cardiac MIBG uptake but normal striatal dopaminergic neurons. RBD is a parasomnia characterized by the suppression of muscular atonia and abnormal, often violent, motor behaviours with a high proportion of aggressive content in the patient’s dreams during REM sleep [1]. RBD can be idiopathic without concomitant neurological disorders, but is mostly reported in patients with neurodegenerative disorders. RBD can be the prodromal symptom of a-synucleinopathies (e.g. Parkinson’s Disease (PD), dementia with Lewy bodies (LBD), multiple system atrophy (MSA) or less frequently, of tauopathies, such as progres- sive supranuclear palsy (PSP) [2]. DAT-SPECT is a marker of nigros- triatal degeneration used in the diagnostic workup of the parkinsonian syndromes. Patients with idiopathic RBD usually show either normal or decreased striatal dopamine transporter binding, sometimes in the absence of neurological symptoms [2,3]. Similarly to previous reports [3], our patient showed both a normal neurologic examination and a normal DAT-scan. Cardiac MIBG scintigraphy is a useful tool for differentiating patients with Lewy body pathology, such as PD and LBD from those with atypical parkinsonian syndromes (e.g., PSP or MSA) [4]. MIBG uptake reflects presynaptic sympathetic system integrity, and reduced myocardial uptake of the tracer suggests cardiac sympa- thetic dysfunction or denervation [4]. Indeed, cardiac MIBG uptake has been found markedly reduced in PD and LBD, whereas it was normal in a patient with PSA and MSA. In our patient, cardiac MIBG uptake was markedly decreased, a finding suggestive of Lewy body pathology. In agreement with our data, a recent study showed a marked reduction of the cardiac MIBG uptake in 13 patients with idiopathic RBD, suggesting that idiopathic RBD in older patients may be considered a forme fruste of a-synucleinop- athy (PD or LBD) [4]. However, these authors did not perform q The review of this paper was entirely handled by the Co-Editor-in-Chief, Professor R.F. Pfeiffer. Contents lists available at ScienceDirect Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis 1353-8020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.parkreldis.2009.03.008 Parkinsonism and Related Disorders 15 (2009) 789–791