LB: Are Prodromal Swallowing Deficits in Asymptomatic Infants with Spinal Muscular Atrophy a Source for Select Cases of Suboptimal Treatment Outcomes?

Topic:

Translational Research

Poster Number: 496 LBM

Author(s):

Katlyn McGrattan, PhD, University of Minnesota, Randal Richardson, MD, Gillette Children's, Graham Schenck, PhD, Gillette Children's, Robert Graham, MD, Boston Children's Hospital, Basil Darras, MD, Boston Children's Hospital, Peter Karachunski, MD, University of Minnesota, Irena Wilson, BS, University of Minnesota, Alicia Hofelich Mohr, PhD, University of Minnesota, Mackenzi5 Coker, MS, University of Florida, Caitlyn Carey, MS, University of Florida, Carmen Leon Astudillo, MD, University of Florida

Background: Administration of disease modifying treatments in presymptomatic patients with Spinal Muscular Atrophy (SMA) enables the majority of infants to maintain good swallowing function, though not all. This discrepancy in outcomes is postulated to reflect the presence of prodromal motor neuron loss. However, no investigations have examined baseline swallowing integrity to know for certain.

Objective: In this investigation we characterized swallowing physiology and function among presymptomatic infants with SMA prior to the effects of disease modifying treatments. Infants with presymptomatic SMA who underwent a videofluoroscopic swallow study as part of routine presymptomatic high-risk referral were identified from 4 children’s hospitals. Infants who had been on a DMT for >1 month were excluded to reduce potential of pharmaceutical treatment effects. Charts were reviewed and VFSS exams evaluated for measures of biomechanics during intake of thin liquids using BabyVFSSImP. Data was reported using descriptive statistics.

Results: 25 infants were included in the investigation. The majority of infants had 2 copies of SMN 2 (61%), and all were consuming full oral nutrition without reported dysphagia symptoms. Average age at the time of VFSS was 19+-13 days old. Infants sucked with an average of 1.85  0.58 sucks/swallow. Examination of airway protection revealed nearly all infants exhibited penetration (91%), which occurred an average of 22 +- 15% of swallows. Aspiration was observed less frequently than penetration, though present in 30% of infants. Bolus clearance was generally preserved, with only 1 infant exhibiting profound impairments as characterized by the majority of the bolus remaining after the swallow. This was due to insufficient opening of the pharyngoesophageal segment on select swallows.

Conclusions: Presymptomatic infants with SMA frequently have imperfections in swallowing biomechanics frequently impeding airway protection. Future investigations examining how these deficits compare to healthy infants and change with prolonged administration of DMT are warranted.