About

Nadine P. Connor is a Professor in the Department of Otolaryngology-Head and Neck Surgery at the University of Wisconsin-Madison. She holds a PhD in Neurophysiology from the University of Wisconsin and serves as the co-director of the Voice Research Training Program. Her research interests include voice and swallowing disorders, head and neck cancer, aging, and neuromuscular function in the head and neck. Her primary focus is on the effects of aging on the upper airway, including the larynx and tongue, studying muscle physiology, structure, and nerve-muscle connections to understand mechanisms of muscular plasticity within these regions and exploring how these processes can be reversed or prevented through exercise and other treatments. Dr. Connor has contributed to advancing knowledge in her field through her research, including recent work on swallowing problems in individuals with Alzheimer’s disease, supported by a significant federal research grant.

Research topics

• Surgery
• Medicine
• Internal medicine
• Physical therapy
• Intensive care medicine
• Pathology
• Anatomy
• Family medicine
• Nursing
• Urology

Selected publications

• Bulbar sensorimotor function in a rat model of Alexander disease

  SSRN Electronic Journal · 2026-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Swallowing characteristics in Down syndrome at an advanced age: a preclinical study in the Ts65Dn mouse model

  Frontiers in Neurology · 2026-01-21

  articleOpen access

  Down syndrome (DS) occurs in approximately one in 800 births worldwide and is associated with various medical complications including swallowing impairments and dysphagia. Advances in childhood survival have led to an increased number of people with DS reaching older ages. Aging is generally accompanied by changes in sensory and motor functions, including those involved in swallowing. Swallowing impairments can lead to complications such as malnutrition, dehydration, and aspiration pneumonia. Despite the multifactorial nature of swallowing impairments in older people with DS, research in this area remains limited, with most studies focusing on pediatric populations. We hypothesized that aged Ts65Dn mice (mouse model of DS; 14 males, 15 females) would demonstrate significant impairments in swallowing performance on quantitative measures derived from videofluoroscopic swallow studies, relative to age-matched euploid controls (genetically typical mice; 14 males and 15 females). Statistical analyses included two-way ANOVA for genotype and sex effects. The Ts65Dn group exhibited significantly lower swallow rates, longer inter-swallow intervals (ISI), increased jaw cycle: swallow ratios (JSR), and lower jaw excursion rates (JER) than euploid controls. Body weight was significantly lower in the Ts65Dn group. These findings confirm persistent swallowing impairments in aged Ts65Dn mice, supporting their use as a model for studying swallowing mechanisms, provide critical insights into swallowing impairments in aging DS and support the need for specialized clinical interventions for swallowing disorders in this population.

  PublisherOA PDFDOI

• Impact of Cre/LoxP-Mediated Chromosome Engineering Technology on Down Syndrome Research

  2025-01-01

  book-chapter
  PublisherDOI

• Secondary analyses of swallowing efficiency and safety outcomes following thyroidectomy versus thyroidectomy plus prophylactic central neck dissection

  Thyroid Research · 2025-09-15

  articleOpen access

  BACKGROUND: Swallowing complaints are common following total thyroidectomy, though an exact mechanism of patient-reported swallowing symptoms following thyroidectomy is currently lacking. This secondary, blinded analysis of data collected in a randomized, controlled clinical trial hypothesized that patients randomly assigned to the central neck dissection group would exhibit increased aspiration and pharyngeal residue on videofluoroscopic swallowing evaluation, and reduced patient-rated swallowing outcomes, as compared to patients randomized to thyroidectomy alone. We further hypothesized that blinded analysis would reveal worse swallowing function two-weeks post-surgery when compared to their pre-operative status to explain qualitative patient-reported dysphagia symptoms. METHODS: Thirty-two participants randomized to total thyroidectomy treatment with or without central neck dissection underwent pre- and post-surgical evaluation of swallowing outcomes, including videofluoroscopic Penetration/Aspiration Scale ratings, Normalized Residue Ratio Scale measures of valleculae and pyriform sinus residue, and EAT-10 patient-rated outcomes. RESULTS: No statistically significant differences were found post-surgery between randomized treatment groups for patient-rated EAT-10 scores (p = 0.2406), penetration/aspiration scale (p = 0.4465) or Normalized Residue Rating Scale scores for either vallecular or pyriform sinus sites. When group data were combined for analysis of differences between pre- and post-operative swallow performance, no statistically significant differences were found in patient-rated EAT-10 scores (p = 0.1374), penetration/aspiration scale (p = 0.7588) or Normalized Residue Rating Scale scores. CONCLUSIONS: Measures of penetration/aspiration and pharyngeal residue failed to substantiate perceptions of post-operative dysphagia reported by patients undergoing total thyroidectomy with or without central neck dissection. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02138214.

  PublisherOA PDFDOI

• Reliability of 3-D/4-D Ultrasound Contouring of Tongue Surface During Swallowing

  Ultrasound in Medicine & Biology · 2025-05-03 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Cellular and transcriptomic changes by the supplementation of aged rat serum in human pluripotent stem cell-derived myogenic progenitors

  Frontiers in Cell and Developmental Biology · 2024-10-15

  articleOpen access

  Introduction: The changing composition of non-cell autonomous circulating factors in blood as humans age is believed to play a role in muscle mass and strength loss. The mechanisms through which these circulating factors act in age-related skeletal muscle changes is not fully understood. In this study, we used human myogenic progenitors derived from human pluripotent stem cells to study non-cell autonomous roles of circulating factors during the process of myogenic differentiation. Methods: Myogenic progenitors from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) were supplemented with serum samples from aged or young Fischer 344 × Brown Norway F1-hybrid rats. The effect of aged or young serum supplementation on myogenic progenitor proliferation, myotube formation capacity, differentiation, and early transcriptomic profiles were analyzed. Results: We found that aged rat serum supplementation significantly reduced cell proliferation and increased cell death in both ESC- and iPSC-derived myogenic progenitors. Next, we found that the supplementation of aged rat serum inhibited myotube formation and maturation during terminal differentiation from progenitors to skeletal myocytes when compared to the cells treated with young adult rat serum. Lastly, we identified that gene expression profiles were affected following serum supplementation in culture. Discussion: model possibly simulate non-cell autonomous contributions of blood composition to age-related processes in human skeletal muscle.

  PublisherOA PDFDOI

• Vocal and tongue exercise in early to mid-stage Parkinson disease using the Pink1-/- rat

  Brain Research · 2024-04-27 · 4 citations

  articleOpen access
  PublisherOA PDFDOI

• Altered tongue muscle contractile properties coincide with altered swallow function in the adult Ts65Dn mouse model of down syndrome

  Frontiers in Neurology · 2024-03-22 · 3 citations

  articleOpen accessSenior author

  Purpose: Down syndrome (DS) is a developmental disability associated with difficulties in deglutition. The adult Ts65Dn mouse model of DS has been previously shown to have differences in measures of swallowing compared with euploid controls. However, the putative mechanisms of these differences in swallowing function are unclear. This study tested the hypothesis that the Ts65Dn genotype is associated with atypical measures of tongue muscle contractile properties, coinciding with atypical swallow function. Methods: = 16 female, 14 male) were evaluated through videofluoroscopy swallow studies (VFSS) to quantify measures of swallowing performance including swallow rate and inter-swallow interval (ISI). After VFSS, retrusive tongue muscle contractile properties, including measures of muscle fatigue, were determined using bilateral hypoglossal nerve stimulation. Results: The Ts65Dn group had significantly slower swallow rates, significantly greater ISI times, significantly slower rates of tongue force development, and significantly greater levels of tongue muscle fatigue, with lower retrusive tongue forces than controls in fatigue conditions. Conclusion: Tongue muscle contractile properties are altered in adult Ts65Dn and coincide with altered swallow function.

  PublisherOA PDFDOI

• Developmental deglutition and intrinsic tongue muscle maturation phenotypes in the Ts65Dn mouse model of Down syndrome

  Frontiers in Neurology · 2024-12-11 · 1 citations

  articleOpen accessSenior author

  Introduction: Down syndrome (DS) is associated with difficulties with feeding during infancy and childhood. Weaning, or transitioning from nursing to independent deglutition, requires developmental progression in tongue function. However, little is known about whether postnatal tongue muscle maturation is impacted in DS. This study tested the hypothesis that the Ts65Dn mouse model of DS has developmental delays in deglutition, comprised of differences in eating and drinking behaviors relative to euploid controls, coinciding with atypical measures of intrinsic tongue muscle microanatomy. Methods: The Ts65Dn mouse model of DS and euploid controls were evaluated at 7 days of age (p7; nursing), p21 (weaning), and p35 (mature deglutition) (n = 13-18 mice per group). Eating behavior, drinking behavior, and body weight changes were quantified in p21 and p35 mice through the use of automated monitoring over 24 h. Intrinsic tongues of mice at all three ages were sectioned and stained to permit quantification of the sizes of the four major intrinsic tongue muscles. Transverse intrinsic tongue muscles were evaluated for myofiber size (average myofiber cross sectional area (CSA) of all fibers, MyHC2a fibers, MyHC 2b fibers, and minimum Feret fiber diameter), and percentage of MyHC isoforms (%MyHC2a + fibers, and %MyHC 2b + fibers) in anterior, middle, and posterior regions. Results: Ts65Dn showed significant differences from euploid in deglutition measures. Compared to euploid, Ts65Dn also showed differences in intrinsic tongue muscle microanatomy and biology. Specifically, Ts65Dn intrinsic tongues had smaller transverse muscle myofiber size measures than control in the anterior and middle tongue, but not in the posterior tongue. Conclusion: Differences in intrinsic tongue muscles coincide with feeding phenotypes in the Ts65Dn mouse model of DS.

  PublisherDOI

• Early ultrasonic vocalization deficits and related thyroarytenoid muscle pathology in the transgenic TgF344-AD rat model of Alzheimer’s disease

  Frontiers in Behavioral Neuroscience · 2024-01-23 · 7 citations

  articleOpen access

  Background Alzheimer’s disease (AD) is a progressive neurologic disease and the most common cause of dementia. Classic pathology in AD is characterized by inflammation, abnormal presence of tau protein, and aggregation of β-amyloid that disrupt normal neuronal function and lead to cell death. Deficits in communication also occur during disease progression and significantly reduce health, well-being, and quality of life. Because clinical diagnosis occurs in the mid-stage of the disease, characterizing the prodrome and early stages in humans is currently challenging. To overcome these challenges, we use the validated TgF344-AD (F344-Tg(Prp-APP, Prp-PS1)19/Rrrc) transgenic rat model that manifests cognitive, behavioral, and neuropathological dysfunction akin to AD in humans. Objectives The overarching goal of our work is to test the central hypothesis that pathology and related behavioral deficits such as communication dysfunction in part manifest in the peripheral nervous system and corresponding target tissues already in the early stages. The primary aims of this study are to test the hypotheses that: (1) changes in ultrasonic vocalizations (USV) occur in the prodromal stage at 6 months of age and worsen at 9 months of age, (2) inflammation as well as AD-related pathology can be found in the thyroarytenoid muscle (TA) at 12 months of age (experimental endpoint tissue harvest), and to (3) demonstrate that the TgF344-AD rat model is an appropriate model for preclinical investigations of early AD-related vocal deficits. Methods USVs were collected from male TgF344-AD ( N = 19) and wildtype (WT) Fischer-344 rats ( N = 19) at 6 months ( N = 38; WT: n = 19; TgF344-AD : n = 19) and 9 months of age ( N = 18; WT: n = 10; TgF344-AD : n = 8) and acoustically analyzed for duration, mean power, principal frequency, low frequency, high frequency, peak frequency, and call type. RT-qPCR was used to assay peripheral inflammation and AD-related pathology via gene expressions in the TA muscle of male TgF344-AD rats ( n = 6) and WT rats ( n = 6) at 12 months of age. Results This study revealed a significant reduction in mean power of ultrasonic calls from 6 to 9 months of age and increased peak frequency levels over time in TgF344-AD rats compared to WT controls. Additionally, significant downregulation of AD-related genes Uqcrc2 , Bace2 , Serpina3n , and Igf2, as well as downregulation of pro-inflammatory gene Myd88 was found in the TA muscle of TgF344-AD rats at 12 months of age. Discussion Our findings demonstrate early and progressive vocal deficits in the TgF344-AD rat model. We further provide evidence of dysregulation of AD-pathology-related genes as well as inflammatory genes in the TA muscles of TgF344-AD rats in the early stage of the disease, confirming this rat model for early-stage investigations of voice deficits and related pathology.

  PublisherOA PDFDOI

Recent grants

• NIH Grant R21DC009649

  NIH · $397k · 2012

• NIH Grant R01DC005935

  NIH · $3.3M · 2017

• NIH Grant R01CA176911

  NIH · $1.8M · 2020

• NIH Grant R01DC014358

  NIH · $2.7M · 2022

• NIH Grant R41DC009101

  NIH · $100k · 2010

Frequent coauthors

• John A. Russell

  41 shared

• Heidi Kletzien

  University of Wisconsin–Madison

  23 shared

• Glen Leverson

  University of Wisconsin–Madison

  21 shared

• Nicole Rogus‐Pulia

  William S. Middleton Memorial Veterans Hospital

  20 shared

• Gregory K. Hartig

  20 shared

• Rebecca S. Sippel

  University of Wisconsin–Madison

  20 shared

• Michelle R. Ciucci

  University of Wisconsin–Madison

  19 shared

• Dennis M. Heisey

  United States Geological Survey

  17 shared

Labs

• Connor LabPI