Silber, Michael H.

Abstract Study Objectives Isolated REM sleep behavior disorder (iRBD) carries a high lifetime risk for phenoconversion to a defined neurodegenerative disease (NDD) including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. We aimed to examine iRBD patient values and preferences regarding prognostic counseling. Methods One hundred thirteen iRBD patient participants enrolled in the Mayo Clinic iRBD Patient Registry were sent an email survey concerning their values and preferences concerning NDD prognostic counseling and their experiences following diagnosis with iRBD. Results Of 81 respondents (71.7% response rate), the majority were men (74.0%) with an average age of 65.7 (±9.7) years. Responses indicated a strong preference toward receiving prognostic information about possible future NDD development. 92.5% of respondents felt knowledge concerning personal NDD risk was important, while 87.6% indicated prognostic discussions were important to maintaining trust in their physician. 95.7% indicated a desire for more information, while only 4.3% desired less information regarding their NDD prognostic risk. Most respondents strongly agreed that prognostic information was important to discuss with their family and friends and inform future life planning, and most expressed interest in learning more about future neuroprotective therapies and symptomatic treatments for parkinsonism and dementia. Conclusions Most iRBD patients indicated strong preferences for disclosure of NDD prognostic risk and indicated that prognostic information was important for family discussions and future life planning. Future broader surveys and qualitative studies of clinic-based and ultimately community dwelling iRBD patients’ values and preferences are needed to guide appropriately tailored and individualized prognostic counseling approaches following iRBD diagnosis.

Risk of sudden death in multiple system atrophy (MSA) is greatest during sleep with unknown mechanisms. We compared nocturnal pulse event frequency in 46 MSA patients and age‐/sex‐matched controls undergoing overnight pulse oximetry. Nocturnal oxyhemoglobin desaturation indices and pulse event indices (PEIs) were recorded, and relationships between pulse oximetry variables and survival were analyzed. MSA patients had lower PEI (3.1 ± 5.3 vs. 12.8 ± 10.8, p < 0.001) despite greater hypoxic burden and similar frequency of respiratory events. Nocturnal pulse events were not associated with severity of daytime autonomic failure. Two MSA patients had suspected sudden death, both with severely reduced PEI. MSA patients have fewer nocturnal pulse events compared with controls, despite similar respiratory event frequency, suggesting abnormal cardiac responses to sleep‐disordered breathing. Whether this contributes to sudden death in MSA requires further study. ANN NEUROL 2023;93:205–212

Abstract Introduction Accurate, early diagnosis of isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is crucial given its injury potential and neurological prognosis. We aimed to analyze visual and automated REM sleep without atonia (RSWA) diagnostic thresholds in a current cohort of iRBD patients using submentalis (SM) and individual four limb electromyography (EMG) recordings, including bilateral flexor digitorum superificialis (FDS) and anterior tibialis (AT) during polysomnography. Methods We analyzed RSWA in 20 iRBD patients and 20 age-sex-AHI matched controls who underwent polysomnography between 2017-2021 for phasic burst durations, phasic, tonic, and "any" muscle activity, and automated REM atonia index (RAI). Group RSWA metrics were analyzed with non-parametric comparisons, logistic regression, and receiver operating characteristic (ROC) curves to determine optimal diagnostic cutoff thresholds for iRBD. Correlation explored associative relationships between RSWA metrics, and principal components analysis (PCA) defined determinants of RSWA metric variance. Results All mean RSWA metrics were higher in iRBD patients than controls (p&lt;0.05), except for left and bilateral AT phasic density and duration. RSWA(phasic%, AUC; "any"%, AUC) cutoffs were: SM (6.5%, AUC=90.2; 6.5%, AUC=92.5); L FDS (7.3%, AUC=95.8; 7.3%, AUC=95.8%); R FDS (5.4%, AUC=93.5; 5.8%, AUC=93.2%); Bilateral FDS (10.7%, AUC=96; 15.3%, AUC=95.8); L AT (6.7%, AUC=74.5; 6.7%, AUC=74.8%); R AT (4.7%, AUC=76.8; 4.7%, AUC=76.8%); Bilateral AT (7.5%, AUC=77.5; 7.5%, AUC=77.5%), combined SM/FDS (15.0%, AUC=95.5; 15.1%; AUC=95.8), combined SM/AT (16.5%, AUC=85.8; 21.0%; AUC=88.8),tonic (0.5%; AUC=85.9), and RAI (0.90; AUC=91.4). Phasic burst duration cutoffs were: SM=0.7s (AUC=90.2), L FDS=0.5 s (AUC=83.2), R FDS=0.6 (AUC=85.2), L AT=0.3 s (AUC=65.0) and R AT=0.4 s (AUC=77.0). PCA demonstrated that FDS and combined SM/FDS and SM/AT RSWA metrics best explained RSWA variance and differentiated controls from RBD, while SM and AT alone were less explanatory. Conclusion This study provides evidence for quantitative RSWA diagnostic thresholds applicable in current iRBD populations, and confirms the key importance of FDS to assure accurate iRBD diagnosis. Interestingly, these RSWA diagnostic thresholds are lower than previously determined thresholds, suggesting secular trends toward earlier iRBD detection and heterogeneous disease duration relative to polysomnography acquisition, underscoring the necessity of future large scale prospective, multicenter polysomnographic analyses to determine definitive iRBD diagnostic RSWA thresholds. Support (If Any)

Abstract Introduction REM sleep without atonia (RSWA) is the neurophysiological substrate of REM sleep behavior disorder (RBD), a form of prodromal parkinsonism in most older adults. Isolated RSWA (without clinical RBD) elevation was demonstrated recently in older adults following SARS-CoV2 (COVID-19) infection, but comparison to controls was not reported. We aimed to comparatively analyze RSWA between patients with previous COVID-19 infection and COVID-19 negative controls. Methods 25 patients with previous COVID-19 infection were compared to 25 age-sex matched controls who tested negative for COVID-19 prior to polysomnography. Patients receiving medications known to increase RSWA were excluded. We reviewed medical records to determine clinical features and quantitatively analyzed RSWA in the submentalis (SM) and anterior tibialis (AT) muscles for phasic, tonic, and “any” muscle activity, phasic burst duration, and the automated REM atonia index. Non-parametric analyses compared clinical and polysomnographic features between groups, with combined SM and AT RSWA as the defined primary outcome. The comparative frequency of COVID-19 positive cases and COVID-19 negative controls who met or exceeded proposed isolated RSWA thresholds was also determined. Results COVID-19 patients had significantly greater RSWA than COVID-19 negative controls in the combined SM and AT muscles (p = 0.00076). Most other RSWA metrics were also higher in COVID-19 patients than controls (p&lt;0.03), except tonic muscle activity, phasic burst durations, and RAI. Isolated RSWA occurred more frequently in COVID-19 (9 patients, 36%) than controls (3, 12%; p&gt;0.05). No patients had a clinical history or polysomnographic evidence for parasomnia behavior or a primary neurological condition. Conclusion Quantitative RSWA amounts were comparatively greater in COVID-19 patients than in COVID-19 tested-negative controls, suggesting association of previous COVID-19 infection with central nervous system brainstem dysfunction in the region of the dorsal pons and/or ventromedial medulla. Further prospective studies are needed to determine whether RSWA is a predisposing influence to, or consequence of, COVID-19 infection in these patients, and whether COVID-19 survivors might harbor neurodegenerative risk or disease markers. Support (If Any)

Abstract Introduction Orexin deficiency in cerebrospinal fluid (CSF) was first reported in human narcolepsy in 2001, included in diagnostic criteria for narcolepsy in 2014, and made clinically available at the Mayo Clinic in 2019. The purpose of this publication is to report orexin test utilization and results, and other clinically relevant findings from patients evaluated at Mayo Clinic. Methods We retrospectively reviewed CSF orexin samples and clinical records from patients evaluated at Mayo Clinic from 2019 to 2021. Results A total of 98 internal samples (Rochester, n=56; Arizona, n=25, and Florida, n=17) from 95 patients (mean age 32.4 +/- 16.6 years with 20 %, 52 %, and 28 % of patients &lt; 18, 18 – 40, and &gt; 40 years, respectively, at time of CSF collection; 62 % female) have been submitted for CSF orexin measurement (mean CSF orexin 335.17 +/- 158.3 pg/ml; deficient &lt; 110 pg/ml, n=11, 64 % &lt;=40 years with mean age 32.9 +/- 17.0 years; intermediate 110 – 200 pg/ml, n=8, 100 % &lt;= 40 years with mean age 21.1 +/- 12.8 years; normal &gt; 200 pg/ml, n=79, 57 % &lt;=40 years with mean age 33.5 +/- 16.7). No significant correlation was found between orexin levels, and time of collection (i.e., diurnal variation), gender, or age. Repeat testing was performed on three individuals (ages 10, 14, and 19 years) with a change in category of orexin level found in one patient from an intermediate to a normal level. Conclusion Orexin deficiency was found in 12 % of the patients (64 % of the deficient samples were found at ages &lt;= 40 years). This result may reflect the fact that this test is frequently pursued in clinical patients presenting with inconclusive findings and/or comorbidities. Intermediate orexin levels found in 8 % of the samples (100 % &lt;= 40 years). Although most of the patients tested were female (62.2%) and most were 40 years or younger (72%), no significant correlation was found between orexin levels, and time of collection (i.e., diurnal variation), gender, or age. Support (If Any) none

AbstractBackgroundIsolated REM Sleep Behavior Disorder (iRBD) patients are known to be at high risk for developing an overt synucleinopathy – particularly Dementia with Lewy Bodies (DLB) and Parkinson’s Disease (PD). Reduced nigrostriatal uptake on 123I‐FP‐CIT SPECT reflects dopamine deficiency, which is common in the overt synucleinopathies. We sought to assess how 123I‐FP‐CIT SPECT imaging in iRBD changes longitudinally and whether an abnormal 123I‐FP‐CIT SPECT scan precedes and predicts future transition to an overt synucleinopathy.MethodParticipants with polysomnography‐confirmed iRBD from the Mayo Clinic Alzheimer’s Disease Research Center database +/‐ North American Prodromal Synucleinopathy (NAPS) Consortium who had two or more longitudinal 123I‐FP‐CIT SPECT scans and been followed prospectively for at least 24 months were included in this analysis. Striatonigral dopamine transporter uptake was evaluated semi‐quantitatively with 123I‐FP‐CIT SPECT using DaTQUANT software (GE Healthcare) to calculate z‐scores of putamen uptake.ResultThirty‐five iRBD participants (86% male) were evaluated prospectively (mean 62.5 ± 19.4 months) and underwent two or more 123I‐FP‐CIT SPECT scans at a minimum of 12 months intervals. Thirteen participants (37%) developed an overt synucleinopathy (11 DLB and 2 PD; phenoconverters) and 22 participants (63%) remained as iRBD (stable iRBD). Phenoconverters were older (mean 70.8 ± 7.0 vs 63.4 ± 6.0 years old) and had more negative DaTQUANT putamen z‐scores (mean ‐1.68 ± 1.42 vs ‐0.33 ± 1.52) than stable iRBD participants at baseline. Among phenoconverters, nine participants (69%) had one or more 123I‐FP‐CIT SPECT scans with DaTQUANT putamen z‐score of <‐2.0 prior to phenoconversion, and mean time from initial DaTQUANT putamen z‐score of <‐2.0 to phenoconversion was 36.8 ± 28.7 months. In stable RBD participants, eight participants (36%) showed a decline in DaTQUANT putamen z‐score of >1 between the most recent and the baseline scan, and four participants (18%) presented DaTQUANT putamen z‐score of <‐2.0 at the most recent scan.ConclusionThese findings suggest that a decline in putamen uptake on 123I‐FP‐CIT SPECT in iRBD serves as a predictor and a surrogate biomarker for progression of iRBD to an overt synucleinopathy.

AbstractBackgroundImpaired olfaction has been associated with neurodegenerative diseases and may be a useful tool to aid in diagnosis or track disease progression. We sought to compare olfaction in participants with the clinical diagnoses of idiopathic REM sleep behavior disorder (RBD), dementia with Lewy bodies (DLB), or Alzheimer’s disease dementia (AD).MethodParticipants from the Mayo Clinic Alzheimer’s Disease Research Center database who had a diagnosis of RBD (n=27, 56% male), DLB (n=51, 84% male), or AD (n=83, 47% male), and were given the Brief Smell Identification Test (B‐SIT) were included in this analysis. The B‐SIT score was calculated as the sum of correct responses (12 possible). Scores were categorized as reflecting anosmia (<6), hyposmia (6‐10), and normal olfactory function (>10). All participants underwent clinical and neuropsychological evaluations.ResultGlobal cognition was lower in AD and DLB than RBD (MMSE 21.5 ±4.9 in AD, 23.3 ±4.3 in DLB, 28.8 ± 1.2 in RBD; p <0.001). The mean B‐SIT total score was significantly lower for DLB (4.5 ± 3.1) compared to RBD (7.5 ± 3.0) or AD (7.0 ± 2.7) (p<0.001) using an ANOVA F‐test. Anosmia was present in 76% of DLB, which compared to 32% in RBD, and 32% in AD (p=0.9). Hyposmia was present in 18% of DLB, 47% of RBD, and 52% of AD (p=ns). Of 22 patients with normal olfaction, X% were DLB, X% RBD, and X% AD (p=X). An item analysis illustrated that participants with DLB were less likely to identify Menthol, Clove, Strawberry, Smoke, and Soap than those with RBD and AD. On serial examination, 12 RBD (60%) patients’ B‐SIT score decreased by at least one point at their most recent visit compared to their baseline visit.ConclusionThese findings suggest that impaired olfactory function is frequent in RBD, DLB and AD, with olfaction being worst in DLB in this cohort. Olfaction was declining in most of those with RBD who underwent serial evaluations. Further analyses are needed to determine if any scents are more sensitive to phenotype, progression, and degree of cognitive impairment. Supported by: NIH grants AG016574, NS100620, AG056639, AG015866