Publications by authors named "Pierz K"

Background: Orthopaedic surgical intervention in children with Charcot-Marie-Tooth (CMT) often includes triceps surae lengthening (TSL) and foot procedures to address instability and pain due to equinus and cavovarus deformities. These surgeries may unmask underlying weakness in this progressive disease causing increased calcaneal pitch and excessive dorsiflexion in terminal stance leading to crouch. The purpose of this study was to evaluate changes in ankle function during gait following TSL surgery in children with CMT.

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Background: The assessment of gait disorders in patients with neuromotor conditions, such as cerebral palsy (CP), has been a focus of clinical and research attention, with electromyography (EMG) offering a nuanced understanding of neurological and neuromuscular disorders. However, the interpretation of EMG data in the context of gait analysis remains challenging due to the complexity of neuromotor dynamics and variability in assessment methodologies.

Research Question: To which consensus can we get in a group of experts in the fields of neurological and neuromuscular disorders, biomechanics, and clinical gait analysis to establish standardized protocols and a common language for the measurement and analysis of EMG data in gait disorders, particularly in people living with CP?

Methods: A three-round Delphi process was conducted from February to September 2023 to gather opinions of 53 experts on the use of surface EMG data during gait in the context of CP.

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Article Synopsis
  • Children with cerebral palsy often experience foot deformities, which require precise evaluation for effective treatment and monitoring.
  • This study tested the reliability of a new photo-based assessment tool called the Modified Foot Posture Index (MFPI) among 13 orthopedic surgeons evaluating foot photographs of 20 children with CP.
  • Results indicated that the MFPI exhibits excellent reliability in measuring foot deformities, making it a noninvasive and practical option for clinical and research settings.
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Article Synopsis
  • The Foot Posture Index-6 (FPI6) is a foot position assessment tool that helps evaluate orthopaedic issues, rating foot position components on a scale from -12 (severe supination) to +12 (severe pronation).
  • This study aims to determine if a simplified three-component version (FPI3) correlates with the FPI6 scores, checking its reliability and the accuracy of video assessments versus live evaluations.
  • A retrospective analysis of 155 participants was conducted, focusing on specific foot components to compare FPI3 and FPI6 scores, looking for symmetry and categorical agreement between both versions. *
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Background: Wellinks is a remote disease management solution that provides novel chronic obstructive pulmonary disease (COPD) care delivery.

Objective: This study evaluated the satisfaction, engagement, and clinical outcomes of Wellinks participants. This study also investigated the cadence of health coaching for patients with COPD.

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The nonlinear response of a beam splitter to the coincident arrival of interacting particles enables numerous applications in quantum engineering and metrology. Yet, it poses considerable challenges to control interactions on the individual particle level. Here, we probe the coincidence correlations at a mesoscopic constriction between individual ballistic electrons in a system with unscreened Coulomb interactions and introduce concepts to quantify the associated parametric nonlinearity.

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Article Synopsis
  • Charcot-Marie-Tooth disease (CMT) leads to muscle weakness and gait issues, making it crucial to comprehend how ankle strength loss impacts walking for treatment evaluation.
  • The study investigates how ankle movement and strength differ by age, CMT type, and disease severity in young individuals with CMT types 1 and 2.
  • Results show that CMT2 patients exhibit lower strength and power in ankle movements compared to CMT1, with age affecting peak ankle positions differently between the two types.
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Background And Objectives: The University of Pennsylvania Smell Identification Test (UPSIT) is commonly used to assess olfaction and screen for early detection of disorders including Parkinson (PD) and Alzheimer disease. Our objective was to develop updated percentiles, based on substantially larger samples than previous norms, to more finely discriminate age- and sex-specific UPSIT performance among ≥50-year-old adults who may be candidates for studies of prodromal neurodegenerative diseases.

Methods: The UPSIT was administered cross-sectionally to participants recruited between 2007-2010 and 2013-2015 for the Parkinson Associated Risk Syndrome (PARS) and Parkinson's Progression Markers Initiative (PPMI) cohort studies, respectively.

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Purpose: In children with cerebral palsy, flexion deformities of the knee can be treated with a distal femoral extension osteotomy combined with either patellar tendon advancement or patellar tendon shortening. The purpose of this study was to establish a consensus through expert orthopedic opinion, using a modified Delphi process to describe the surgical indications for distal femoral extension osteotomy and patellar tendon advancement/patellar tendon shortening. A literature review was also conducted to summarize the recent literature on distal femoral extension osteotomy and patellar tendon shortening/patellar tendon advancement.

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The growth parameters for epitaxial growth of graphene on silicon carbide (SiC) have been the focus of research over the past few years. However, besides the standard growth parameters, the influence of the substrate pretreatment and properties of the underlying SiC wafer are critical parameters for optimizing the quality of monolayer graphene on SiC. In this systematic study, we show how the surface properties and the pretreatment determine the quality of monolayer graphene using polymer-assisted sublimation growth (PASG) on SiC.

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Background: Charcot-Marie-Tooth disease (CMT) results in muscle weakness and contracture leading to a wide variety of gait issues including atypical ankle kinematics in both stance and swing. Knowledge of the stance and swing phase kinematic patterns for CMT type 1 (CMT1), the most common CMT type, will improve our understanding of expected gait outcomes and treatment needs to improve gait function.

Research Question: What are the stance/swing phase ankle phenotypes in CMT1?

Methods: A prospective convenience sample of 25 participants with CMT1, ages 7-19 years, underwent comprehensive gait analysis following standard procedures.

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Comprehending far-from-equilibrium many-body interactions is one of the major goals of current ultrafast condensed matter physics research. Here, a particularly interesting but barely understood situation occurs during a strong optical excitation, where the electron and phonon systems can be significantly perturbed and the quasiparticle distributions cannot be described with equilibrium functions. In this work, we use time- and angle-resolved photoelectron spectroscopy to study such far-from-equilibrium many-body interactions for the prototypical material graphene.

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Purpose: The purpose of this study was to establish consensus for the assessment of foot alignment and function in ambulatory children with cerebral palsy, using expert surgeon's opinion through a modified Delphi technique.

Methods: The panel used a five-level Likert-type scale to record agreement or disagreement with 33 statements regarding the assessment of foot alignment and function. Consensus was defined as at least 80% of responses being in the highest or lowest of two of the five Likert-type ratings.

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Purpose: The purpose of this study was to develop consensus for the surgical indications of anterior distal femur hemiepiphysiodesis in children with cerebral palsy using expert surgeon opinion through a modified Delphi technique.

Methods: The panel used a 5-level Likert-type scale to record agreement or disagreement with 27 statements regarding anterior distal femur hemiepiphysiodesis. Consensus was defined as at least 80% of responses being in the highest or lowest 2 of the Likert-type ratings.

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Purpose: There is marked variation in indications and techniques for hamstring surgery in children with cerebral palsy. There is particular uncertainty regarding the indications for hamstring transfer compared to traditional hamstring lengthening. The purpose of this study was for an international panel of experts to use the Delphi method to establish consensus indications for hamstring surgery in ambulatory children with cerebral palsy.

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Background: The purpose of this study was to determine the differences in billable provider charges between single event multilevel surgery (SEMLS) based on comprehensive gait analysis and a staged surgical approach (SSA) without comprehensive gait analysis for the orthopedic treatment of ambulatory children with cerebral palsy (CP).

Methods: The charges associated with nine common orthopedic surgical combinations (both unilateral and bilateral, soft tissue or soft tissue plus bony) for children with CP were determined and compared between SEMLS and SSA. The charges included surgical, anesthesia, operating room, recovery room, hospital stay, physical therapy, and, for SEMLS only, comprehensive computerized gait analysis.

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Background: Increased knee flexion at initial contact and in stance is a common problem for children with cerebral palsy. Surgical correction with percutaneous hamstring lengthening is an alternative to open hamstring lengthening; however, outcomes are less well documented, and there is concern about increasing anterior pelvic tilt. The purpose of this study was to evaluate the short-term outcomes of percutaneous hamstring lengthenings in children with cerebral palsy using comprehensive gait analysis techniques.

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Purpose: The purpose of this study was for an international panel of experts to establish consensus indications for distal rectus femoris surgery in children with cerebral palsy (CP) using a modified Delphi method.

Methods: The panel used a five-level Likert scale to record agreement or disagreement with 33 statements regarding distal rectus femoris surgery. The panel responded to statements regarding general characteristics, clinical indications, computerized gait data, intraoperative techniques and outcome measures.

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A new type of graphene-based quantum Hall standards is tested for electrical quantum metrology applications at alternating current (ac) and direct current (dc). The devices are functionalized with Cr(CO) to control the charge carrier density and have branched Hall contacts based on NbTiN superconducting material. The work is an in-depth study about the characteristic capacitances and related losses in the ac regime of the devices and about their performance during precision resistance measurements at dc and ac.

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Background: Charcot-Marie-Tooth disease (CMT) results in distal muscle weakness that leads to gait difficulties in both the stance and swing phases, thus limiting function in the community. A primary purpose of ankle foot orthoses (AFOs) is to improve gait function; however, little is known about what AFOs are prescribed and how they benefit children with CMT.

Research Question: To determine the impact of previously prescribed AFOs on gait in children with CMT using comprehensive gait analysis techniques.

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Purpose: Equinus is the most common deformity in cerebral palsy (CP) and gastrocsoleus lengthening (GSL) is the most commonly performed surgery to improve gait and function in ambulatory children with CP. Substantial variation exists in the indications for GSL and surgical technique. The purpose of this study was to review surgical anatomy and biomechanics of the gastrocsoleus and to utilize expert orthopaedic opinion through a Delphi technique to establish consensus for surgical indications for GSL in ambulatory children with CP.

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The purpose of this study is to assess how Charcot-Marie-Tooth disease, a group of inherited peripheral neuropathies that result in distal weakness, affects walking velocity over time in comparison to age-matched controls. Comprehensive gait analysis of 57 children (mean age 12.0, SD 3.

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