Faculty Bibliography

Von Economo neurons (VENs) and fork cells are principally located in the anterior cingulate cortex (ACC) and the frontoinsular cortex (FI). Both of these regions integrate inputs from the autonomic nervous system (ANS) and are involved in decision-making and perception of the emotional states of self and others. Familial dysautonomia (FD) is an orphan disorder characterized by autonomic dysfunction and behavioral abnormalities including repetitive behavior and emotional rigidity, which are also seen in autism spectrum disorder. To understand a possible link between the ANS and the cortical regions implicated in emotion regulation we studied VENs and fork cells in an autonomic disorder. We determined the densities of VENs, fork cells, and pyramidal neurons and the ratio of VENs and fork cells to pyramidal neurons in ACC and FI in 4 FD patient and 6 matched control brains using a stereologic approach. We identified alterations in densities of VENs and pyramidal neurons and their distributions in the ACC and FI in FD brains. These data suggest that alterations in migration and numbers of VENs may be involved in FD pathophysiology thereby supporting the notion of a functional link between VENs, the ANS and the peripheral nervous system in general.

Head and neck tumors can affect afferent baroreceptor neurons and either interrupt or intermittently increase their signaling, causing blood pressure to become erratic. When the afferent fibers of the baroreflex are injured by surgery or radiotherapy or fail to develop as in familial dysautonomia, their sensory information is no longer present to regulate arterial blood pressure, resulting in afferent baroreflex failure. When the baroreflex afferents are abnormally activated, such as by paragangliomas in the neck, presumably by direct compression, they trigger acute hypotension and bradycardia and frequently syncope, by a mechanism similar to the carotid sinus syndrome. We describe our observations in a large series of 23 patients with afferent baroreflex dysfunction and the cardiovascular autonomic features that arise when the sensory baroreceptor neurons are injured or compressed. The management of afferent baroreceptor dysfunction is limited, but pharmacological strategies can mitigate blood pressure swings, improve symptoms, and may reduce hypertensive organ damage. Although rare, the prevalence of afferent baroreflex dysfunction appears to be increasing in middle-aged men due to human papillomavirus related oropharyngeal cancer.

Objective: To develop a clinical score to distinguish between the parkinsonian variant of multiple system atrophy (MSA-P) and Parkinson's disease (PD).
Background(s): The differential diagnosis between MSA-P and PD is often difficult, particularly early in the disease course.
Method(s): We compared patients with probable MSA-P and with PD with a disease duration of <3 years, selected from those who were enrolled in the Natural History Study of the Synucleinopathies, an international prospective observational study. Detailed clinical neurological, and autonomic parameters were assessed at enrollment using UMSARS part I, II and IV; Schrag quality of life (QoL) scale; burden of autonomic dysfunction by COMPASS-31 scale; smell function using the UPSIT; cardiovascular autonomic function using heart rate variability during deep-breathing, analysis of the Valsalva maneuver, orthostatic stress test, plasma catecholamine levels during supine rest and after head-up tilt; and cognitive evaluation using MoCA. Positive and negative likelihood ratios (LR) were obtained for each variable assessed. Multiple iterations of a composite score based on sequential addition of variables with the highest diagnostic accuracy were created by multiplying each variable's LR and applying a logarithmic function.
Result(s): Fifty-eight MSA-P and 53 PD patients had a disease duration of less than 3 years. The vast majority of patients had been diagnosed within the last 12 months (81% MSA-P and 66% PD patients). MSA-P patients were more frequently female (53% vs. 30% p<0.05) and younger at diagnosis (63+/-8 years vs. 71+/-8 years, p<0.001). A 7-item score comprising the bladder weighted subscore of the COMPASS-31, UMSARS's part 1, UPSIT, hyperreflexia, the motor subscore of Schrag's MSA quality of life scale, falls within 3 years of diagnosis, and new or increased snoring resulted in a ROC curve AUC of 0.983, with excellent 93% sensitivity and 98% specificity to distinguish early MSA-P from PD.
Conclusion(s): We propose a scale of 7 clinical items to distinguish early stage MSA-P from PD. It considers urinary function, olfactory function, corticospinal signs, performance of activities of daily living, motor symptoms burden on quality of life, frequent early falls and sleep disordered breathing. We are now prospectively validating the scale to determine its predictive value in our prodromal cohort. (Figure Presented)

Objective: To confirm: 1) clinical efficacy and safety of once-daily oral ampreloxetine in a 4-week double-blind (

Objective: To study the rate of progression of multiple system atrophy (MSA) and assess for a potential ceiling effect of the Unified Multiple System Atrophy Rating Scale (UMSARS).
Background(s): Disease progression of MSA as measured by UMSARS varied significantly in natural history studies. Reported 1-year UMSARS-1 and UMSARS-2 progression rates ranged from 3.9 to 6.5 and 3.5 to 8.2 respectively. We hypothesize that this variability is due, at least in part, to differences in severity at enrollment and a potential ceiling effect in the scale, so that patients in more advanced stages may appear to worsen less, which would have important implications for clinical trial design.
Method(s): We analyzed the rate of change in the UMSARS in a large international cohort of well-characterized patients with a clinical diagnosis of possible or probable MSA enrolled in the Natural History Study of Synucleinopathies. Annualized progression rates were obtained using 2-year follow-up data.
Result(s): Three hundred and forty nine patients (61.4+/-7.9 years old) with MSA were enrolled. Disease duration was 4.5+/-5.1 years. 143 patients completed 1-year evaluations and 61 completed the 2-year evaluation. The 12-month progression rates were 5.4+/-5.1 for the UMSARS-I, 5.9+/-5.3 for the UMSARS-II, and 11.8+/-9.6 for the total score. The 24-month progression rates were 10.8+/-7.3 for the UMSARS-I, 12.2+/-7.9 for the UMSARSII, and 22.6+/-13.7 for the total score. Annualized progression rates were divided according to their baseline UMSARS-I and UMSARS II. There was a significant (p = 0.0153) inverse relationship between rate of progression and UMSARS-I at baseline. A similar, but not significant trend was observed with UMSARS-II at baseline.
Conclusion(s): The rate of progression as measured by UMSARS is influenced by the baseline disease severity. A possible ceiling effect should be considered when planning enrollment, power calculations, and outcome measures in clinical trials

KEY POINTS/CONCLUSIONS:Individuals with Hereditary Sensory & Autonomic Neuropathy type III (HSAN III), also known as Riley-Day syndrome or Familial Dysautonomia, do not have functional muscle spindle afferents but do have essentially normal cutaneous mechanoreceptors Lack of muscle spindle feedback from the legs may account for the poor proprioception at the knee and the ataxic gait typical of HSAN III Given that functional muscle spindle afferents are also absent in the upper limb, we assessed whether proprioception at the elbow was likewise compromised Passive joint angle matching showed that proprioception was normal at the elbow, suggesting that individuals with HSAN III rely more on cutaneous afferents around the elbow ABSTRACT: Hereditary Sensory & Autonomic Neuropathy type III (HSAN III) is a rare neurological condition that features a marked ataxic gait that progressively worsens over time. We have shown that functional muscle spindle afferents are absent in the upper and lower limbs in HSAN III, and we have argued that this may account for the ataxia. We recently used passive joint angle matching to demonstrate that proprioception of the knee joint is very poor in HSAN III but can be improved towards normal by application of elastic kinesiology tape across the knee joints, which we attribute to the presence of intact cutaneous mechanoreceptors. Here we assessed whether proprioception was equally compromised at the elbow joint, and whether it could be improved through taping. Proprioception at the elbow joint was assessed using passive joint angle matching in 12 HSAN III patients and 12 age-matched controls. There was no difference in absolute error, gradient or correlation coefficient of the relationship between joint angles of the reference and indicator arms. Unlike at the knee, taping did not improve elbow proprioception in either group. Clearly, the lack of muscle spindles compromised proprioception at the knee but not at the elbow, and we suggest that the HSAN III patients rely more on proprioceptive signals from the skin around the elbow. This article is protected by copyright. All rights reserved.

Afferent lesions of the arterial baroreflex occur in familial dysautonomia. This leads to excessive blood pressure variability with falls and frequent surges that damage the organs. These hypertensive surges are the result of excess peripheral catecholamine release and have no adequate treatment. Carbidopa is a selective DOPA-decarboxylase inhibitor that suppresses catecholamines production outside the brain. To learn whether carbidopa can inhibit catecholamine-induced hypertensive surges in patients with severe afferent baroreflex failure, we conducted a double-blind randomized crossover trial in which patients with familial dysautonomia received high dose carbidopa (600 mg/day), low-dose carbidopa (300 mg/day), or matching placebo in 3 4-week treatment periods. Among the 22 patients enrolled (13 females/8 males), the median age was 26 (range, 12-59 years). At enrollment, patients had hypertensive peaks to 164/116 (range, 144/92 to 213/150 mm Hg). Twenty-four hour urinary norepinephrine excretion, a marker of peripheral catecholamine release, was significantly suppressed on both high dose and low dose carbidopa, compared with placebo (P=0.0075). The 2 co-primary end points of the trial were met. The SD of systolic BP variability was reduced at both carbidopa doses (low dose: 17±4; high dose: 18±5 mm Hg) compared with placebo (23±7 mm Hg; P=0.0013), and there was a significant reduction in the systolic BP peaks on active treatment (P=0.0015). High- and low-dose carbidopa were similarly effective and well tolerated. This study provides class Ib evidence that carbidopa can reduce blood pressure variability in patients with congenital afferent baroreflex failure. Similar beneficial effects are observed in patients with acquired baroreflex lesions.