Faculty Bibliography

Patients with Hereditary Sensory & Autonomic Neuropathy type III exhibit marked ataxia, including gait disturbances. We recently showed that functional muscle spindle afferents in the leg, recorded via intraneural microelectrodes inserted into the peroneal nerve, are absent in HSAN III, although large-diameter cutaneous afferents are intact. Moreover, there is a tight correlation between loss of proprioceptive acuity at the knee and the severity of gait impairment. We tested the hypothesis that manual motor performance is also compromised in HSAN III, attributed to the predicted absence of muscle spindles in the intrinsic muscles of the hand. Manual performance in the Purdue pegboard task was assessed in 12 individuals with HSAN III and 11 age-matched healthy controls. The mean (SD) pegboard score (number of pins inserted in 30 s) was 8.11.9 and 8.61.8 for the left and right hand respectively, significantly lower than the scores for the controls (15.01.3 and 16.01.1; p<0.0001). Performance was not improved after applying kinesiology tape over the joints of the hand. In five patients we inserted a tungsten microelectrode into the ulnar nerve at the wrist. No spontaneous or stretch-evoked muscle afferent activity could be identified in any of the 11 fascicles supplying intrinsic muscles of the hand, whereas rich tactile afferent activity could be recorded from four cutaneous fascicles. We conclude that functional muscle spindles are absent in the hand, and most likely absent in the long finger flexors and extensors, and that this largely accounts for the poor manual motor performance in HSAN III.

INTRODUCTION/BACKGROUND:This study aimed to assess the outcomes of mirabegron for the treatment of overactive bladder (OAB) symptoms in patients with Parkinson disease (PD). METHODS:A retrospective study was conducted including patients with PD who received mirabegron 50 mg once daily for OAB symptoms between 2012 and 2017. The primary endpoint was clinical success defined as any improvement in overactive bladder symptoms self-assessed by the patients 6 weeks after mirabegron initiation. Secondary endpoints included number of pads per day, number of nocturia episodes and adverse events. RESULTS:Fifty patients (mean 74 years old) were included. Before being treated with mirabegron, 56% had failed prior anticholinergic therapy. After 6 weeks of mirabegron 50 mg, five patients (11.4%) had a complete resolution of their OAB symptoms; 25 patients (50%) reported improvement, 23 (46%) reported no change and 2(4%) reported worsening of their OAB symptoms. The number of pads per day decreased from 1.5 to 0.9 (p = 0.01) and so did the number of nocturia episodes (from 3 to 2.6/night; p = 0.02). Only 2 adverse events were reported during mirabegron treatment (4%): one dizziness and one diaphoresis, that disappeared after mirabegron discontinuation. After a median follow-up of 19 months, 23 patients (46%) persisted on mirabegron. Persistence rates were 51.5%, 44.6% and 36.4% at 1, 2 and 3 years respectively. CONCLUSION/CONCLUSIONS:Mirabegron has an excellent safety profile and appears to be an effective treatment for overactive bladder symptoms in patients with PD. Further prospective randomized trials are needed to properly assess mirabegron in PD patients.

OBJECTIVE:To test whether the plasma levels of norepinephrine (NE) in patients with neurogenic orthostatic hypotension (nOH) predict their pressor response to droxidopa. METHODS:This was an observational study, which included patients with nOH. All patients had standardized autonomic function testing including determination of venous plasma catecholamine levels drawn through an indwelling catheter while resting supine. This was followed by a droxidopa titration with 100 mg increments in successive days until relief of symptoms, side effects, or the maximum dose of 600 mg was reached. No response was defined as an increase of <10 mm Hg in systolic blood pressure (BP) after 3-minute standing 1 hour after droxidopa administration. Nonlinear regression models were used to determine the relationship between BP response and plasma NE levels. RESULTS:= 0.0023). CONCLUSIONS:In patients with nOH, lower supine resting plasma NE levels are associated with a greater pressor effect of droxidopa treatment. This finding should help identify patients with nOH most likely to respond to standard doses of droxidopa. CLASSIFICATION OF EVIDENCE/METHODS:This study provides Class I evidence that lower supine plasma NE levels accurately identify patients with nOH more likely to have a greater pressor effect from droxidopa.

Introduction: Deep brain stimulation (