Bradley Vaughn | University of North Carolina at Chapel Hill (original) (raw)

Papers by Bradley Vaughn

Neurologic Clinics, 2012

Sleep and epilepsy have a dynamic interaction that presents the clinician opportunities for diagn... more Sleep and epilepsy have a dynamic interaction that presents the clinician opportunities for diagnosis and treatment. Sleep complaints are very common in patients with epilepsy and these complaints may be related to the underlying epilepsy, the treatment of epilepsy or other sleep related issues. Appropriate treatment of epilepsy may improve sleep, and treatment of sleep disorders may reduce the frequency of recurrent seizures. Sleep and sleep deprivation may provoke seizures and can provide further diagnostic information about the seizure type and location. For the clinician, understanding the relationship of sleep and epilepsy expands the diagnostic and therapeutic armamentarium.

Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 5, 2015

Version 2.2 of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and ... more Version 2.2 of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and Associated Events was released on July 1, 2015. The Scoring Manual Editorial Board (previously the Scoring Manual Committee) would like to call attention to the most important changes. As discussed below, there are two new major sections providing rules for the staging of infant sleep and scoring respiratory events in home sleep apnea testing (HSAT) studies. The new sections were approved by the AASM Board of Directors to fill two obvious gaps in the Scoring Manual. The Scoring Manual Editorial Board would like to emphasize that any changes proposed in the manual are done so after long deliberation and consultation with area content experts.

Children

Genetic advances in the past three decades have transformed our understanding and treatment of ma... more Genetic advances in the past three decades have transformed our understanding and treatment of many human diseases including neurogenetic disorders. Most neurogenetic disorders can be classified as "rare disease," but collectively neurogenetic disorders are not rare and are commonly encountered in general pediatric practice. The authors decided to select eight relatively well-known neurogenetic disorders including Down syndrome, Angelman syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, congenital central hypoventilation syndrome, achondroplasia, mucopolysaccharidoses, and Duchenne muscular dystrophy. Each disorder is presented in the following format: overview, clinical characteristics, developmental aspects, associated sleep disorders, management and research/future directions.

Children

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central s... more Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA); however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0-3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO 2 and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population.

Current biology : CB, Aug 26, 2016

Transient episodes of brain oscillations are a common feature of both the waking and the sleeping... more Transient episodes of brain oscillations are a common feature of both the waking and the sleeping brain. Sleep spindles represent a prominent example of a poorly understood transient brain oscillation that is impaired in disorders such as Alzheimer's disease and schizophrenia. However, the causal role of these bouts of thalamo-cortical oscillations remains unknown. Demonstrating a functional role of sleep spindles in cognitive processes has, so far, been hindered by the lack of a tool to target transient brain oscillations in real time. Here, we show, for the first time, selective enhancement of sleep spindles with non-invasive brain stimulation in humans. We developed a system that detects sleep spindles in real time and applies oscillatory stimulation. Our stimulation selectively enhanced spindle activity as determined by increased sigma activity after transcranial alternating current stimulation (tACS) application. This targeted modulation caused significant enhancement of mo...

The Laryngoscope, 2015

OBJECTIVES-Determine whether quantitative geometric measures and a computational fluid dynamic (C... more OBJECTIVES-Determine whether quantitative geometric measures and a computational fluid dynamic (CFD) model derived from medical imaging of children with subglottic stenosis (SGS) can be effective diagnostic and treatment planning tools. STUDY DESIGN-Retrospective chart and imaging review. SETTING-Tertiary Care Hospital SUBJECTS AND METHODS-CT scans (n=17) of children with SGS were analyzed by geometric and CFD methods. Polysomnograms (n=15) were also analyzed. Radiographic data was age/weight flow normalized and compared to an Atlas created from radiographically normal airways. Five geometric, seven CFD, and five polysomnography measures were analyzed. Statistical analysis utilized a two-sample t-test with Bonferroni correction and area under the curve analysis. RESULTS-Two geometric indices (the ratio of the subglottic to mid-tracheal airway; the percent relative reduction of the subglottic airway) and one CFD measure (the percent relative reduction of the hydraulic diameter of the subglottic airway) were significant for determining which children with SGS received surgical intervention. Optimal cutoffs for these values were determined. Polysomnography, the respiratory effort related arousals index was significant only prior to Bonferroni correction for determining which children received surgical intervention. CONCLUSIONS-Geometric and CFD variables were sensitive at determining which patients with SGS received surgical intervention. Discrete, quantitative assessment of the pediatric airway was performed, yielding preliminary data regarding possible objective thresholds for surgical versus non-surgical treatment of disease. This study is limited by its small, retrospective, single institution nature. Further studies to validate these findings and possibly optimize treatment threshold recommendations are warranted.

ChronoPhysiology and Therapy, 2014

Circadian rhythms and sleep influence a variety of physiological functions, including the digesti... more Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their role in normal physiology and the link of their disruption to pathological conditions. Recent work has demonstrated that sleep and circadian factors influence appetite, nutrient absorption, and metabolism. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues, irritable bowel disease, and gastrointestinal cancer. As our knowledge of the link between circadian timing and gastrointestinal physiology grows, so do our opportunities to provide promising diagnostic and therapeutic approaches for gastrointestinal disorders.

Heart rate variability analysis is a dynamic method to estimate the autonomic control over the ca... more Heart rate variability analysis is a dynamic method to estimate the autonomic control over the cardiac cycle. Although dysfunction in this control system may appear spontaneously, other deficits may require provocation of the system. In this article we describe a non-invasive method to perturb the autonomic influences on the cardiac cycle. We recorded the ECG and respiratory pressure of ten healthy volunteers while introducing a random forced oscillation pressure wave onto spontaneous respiration. The heart period time series were determined and the power spectra for the 0.05-0.15, 0.15-0.3 and 0.05-0.4 Hz bands were calculated. The random input did not alter mean heart rate. However, the segments with the forced oscillation input demonstrated, on average, a tenfold increase in spectral power averaged across all subjects, with a maximum observed effect of 100 fold increase in power. This increase in power correlated with the respiratory frequency. This study demonstrates that random noise ventilation, such as used in respiratory forced oscillation impedance estimates, significantly alters the autonomic input to cardiac cycle variability in wake subjects.

Neurologic Clinics, 2012

Sleep and epilepsy have a dynamic interaction that presents the clinician opportunities for diagn... more Sleep and epilepsy have a dynamic interaction that presents the clinician opportunities for diagnosis and treatment. Sleep complaints are very common in patients with epilepsy and these complaints may be related to the underlying epilepsy, the treatment of epilepsy or other sleep related issues. Appropriate treatment of epilepsy may improve sleep, and treatment of sleep disorders may reduce the frequency of recurrent seizures. Sleep and sleep deprivation may provoke seizures and can provide further diagnostic information about the seizure type and location. For the clinician, understanding the relationship of sleep and epilepsy expands the diagnostic and therapeutic armamentarium.

Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 5, 2015

Version 2.2 of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and ... more Version 2.2 of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and Associated Events was released on July 1, 2015. The Scoring Manual Editorial Board (previously the Scoring Manual Committee) would like to call attention to the most important changes. As discussed below, there are two new major sections providing rules for the staging of infant sleep and scoring respiratory events in home sleep apnea testing (HSAT) studies. The new sections were approved by the AASM Board of Directors to fill two obvious gaps in the Scoring Manual. The Scoring Manual Editorial Board would like to emphasize that any changes proposed in the manual are done so after long deliberation and consultation with area content experts.

Children

Genetic advances in the past three decades have transformed our understanding and treatment of ma... more Genetic advances in the past three decades have transformed our understanding and treatment of many human diseases including neurogenetic disorders. Most neurogenetic disorders can be classified as "rare disease," but collectively neurogenetic disorders are not rare and are commonly encountered in general pediatric practice. The authors decided to select eight relatively well-known neurogenetic disorders including Down syndrome, Angelman syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, congenital central hypoventilation syndrome, achondroplasia, mucopolysaccharidoses, and Duchenne muscular dystrophy. Each disorder is presented in the following format: overview, clinical characteristics, developmental aspects, associated sleep disorders, management and research/future directions.

Children

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central s... more Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA); however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0-3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO 2 and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population.

Current biology : CB, Aug 26, 2016

Transient episodes of brain oscillations are a common feature of both the waking and the sleeping... more Transient episodes of brain oscillations are a common feature of both the waking and the sleeping brain. Sleep spindles represent a prominent example of a poorly understood transient brain oscillation that is impaired in disorders such as Alzheimer's disease and schizophrenia. However, the causal role of these bouts of thalamo-cortical oscillations remains unknown. Demonstrating a functional role of sleep spindles in cognitive processes has, so far, been hindered by the lack of a tool to target transient brain oscillations in real time. Here, we show, for the first time, selective enhancement of sleep spindles with non-invasive brain stimulation in humans. We developed a system that detects sleep spindles in real time and applies oscillatory stimulation. Our stimulation selectively enhanced spindle activity as determined by increased sigma activity after transcranial alternating current stimulation (tACS) application. This targeted modulation caused significant enhancement of mo...

The Laryngoscope, 2015

OBJECTIVES-Determine whether quantitative geometric measures and a computational fluid dynamic (C... more OBJECTIVES-Determine whether quantitative geometric measures and a computational fluid dynamic (CFD) model derived from medical imaging of children with subglottic stenosis (SGS) can be effective diagnostic and treatment planning tools. STUDY DESIGN-Retrospective chart and imaging review. SETTING-Tertiary Care Hospital SUBJECTS AND METHODS-CT scans (n=17) of children with SGS were analyzed by geometric and CFD methods. Polysomnograms (n=15) were also analyzed. Radiographic data was age/weight flow normalized and compared to an Atlas created from radiographically normal airways. Five geometric, seven CFD, and five polysomnography measures were analyzed. Statistical analysis utilized a two-sample t-test with Bonferroni correction and area under the curve analysis. RESULTS-Two geometric indices (the ratio of the subglottic to mid-tracheal airway; the percent relative reduction of the subglottic airway) and one CFD measure (the percent relative reduction of the hydraulic diameter of the subglottic airway) were significant for determining which children with SGS received surgical intervention. Optimal cutoffs for these values were determined. Polysomnography, the respiratory effort related arousals index was significant only prior to Bonferroni correction for determining which children received surgical intervention. CONCLUSIONS-Geometric and CFD variables were sensitive at determining which patients with SGS received surgical intervention. Discrete, quantitative assessment of the pediatric airway was performed, yielding preliminary data regarding possible objective thresholds for surgical versus non-surgical treatment of disease. This study is limited by its small, retrospective, single institution nature. Further studies to validate these findings and possibly optimize treatment threshold recommendations are warranted.

ChronoPhysiology and Therapy, 2014

Circadian rhythms and sleep influence a variety of physiological functions, including the digesti... more Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their role in normal physiology and the link of their disruption to pathological conditions. Recent work has demonstrated that sleep and circadian factors influence appetite, nutrient absorption, and metabolism. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues, irritable bowel disease, and gastrointestinal cancer. As our knowledge of the link between circadian timing and gastrointestinal physiology grows, so do our opportunities to provide promising diagnostic and therapeutic approaches for gastrointestinal disorders.

Heart rate variability analysis is a dynamic method to estimate the autonomic control over the ca... more Heart rate variability analysis is a dynamic method to estimate the autonomic control over the cardiac cycle. Although dysfunction in this control system may appear spontaneously, other deficits may require provocation of the system. In this article we describe a non-invasive method to perturb the autonomic influences on the cardiac cycle. We recorded the ECG and respiratory pressure of ten healthy volunteers while introducing a random forced oscillation pressure wave onto spontaneous respiration. The heart period time series were determined and the power spectra for the 0.05-0.15, 0.15-0.3 and 0.05-0.4 Hz bands were calculated. The random input did not alter mean heart rate. However, the segments with the forced oscillation input demonstrated, on average, a tenfold increase in spectral power averaged across all subjects, with a maximum observed effect of 100 fold increase in power. This increase in power correlated with the respiratory frequency. This study demonstrates that random noise ventilation, such as used in respiratory forced oscillation impedance estimates, significantly alters the autonomic input to cardiac cycle variability in wake subjects.