Medial Gastrocnemius Muscle–Tendon Junction and Fascicle Lengthening across the Range of Motion Analyzed in 2-D and 3-D Ultrasound Images

Ultrasound imaging modalities offer a clinically viable method to visualize musculoskeletal structures. However, proper data comparison between investigations is compromised because of a lack of measurement error documentation and method standardization. This investigation analyzes the reliability and validity of extracting medial gastrocnemius belly and fascicle lengths and pennation angles in different ankle joint positions, across the full range of motion, in a cohort of 11 children with spastic cerebral palsy and 11 typically developed children. Each of these parameters was extracted from two consecutive acquisitions, using both 2-D and 3-D ultrasound images. The findings suggest that the muscle tendon junction extraction in 2-D images can be a suitable parameter for analyzing medial gastrocnemius muscle length in typically developed children and children with spastic cerebral palsy, although averaging over multiple measurements is recommended to reduce variability. More caution should be taken when performing analyses based on fascicle length.     

Acute interstitial nephritis associated with salmonellosis

Acute interstitial nephritis (AIN) is a common cause of acute renal failure. We report a case of AIN, confirmed by renal biopsy, that developed in a patient with typhoid fever due to a Salmonella hadar infection. AIN secondary to Salmonella infection is a rare complication that has only been described twice in the literature. Salmonella should be added to the list of possible causes of AIN.     

Quantitative Effect of Pelvic Position on Radiographic Assessment of Acetabular Component Position

Background

Intraoperative fluoroscopy aims to improve component position in total hip arthroplasty. Measurement bias related to image quality, however, has not been quantified. We aim to quantify measurement bias in the interpretation of acetabular component position as a function of pelvis and fluoroscopic beam position in a simulated supine total hip arthroplasty model.

Vestibular dysfunction is a manifestation of 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11.2DS) is the second most common cause of developmental delay after Down syndrome. Impaired cognitive development is highly prevalent, but also motor abnormalities such as hypotonia and delays in achieving motor milestones are described. Instability is frequently detected in children, adolescents, and adults and is mostly attributed to their limited motor performance. Until now, vestibular function has not been investigated in these patients, despite the growing evidence that they often have inner ear malformations. The aim of this prospective study was to identify the presence and character of vestibular dysfunction in 22q11.2DS. We investigated 23 subjects with proven 22q11.2DS, older than the age of 12. We performed caloric testing and pendular rotation chair tests with videonystagmography, cervical vestibular‐evoked myogenic potential (c‐VEMP)‐testing, and posturography. Additional otoscopy and audiometry were performed on all subjects. We found a unilateral caloric hypofunction in 55% of patients, a certain absent c‐VEMP response in 15% of ears, an inconclusive c‐VEMP response in 33% of ears, and abnormal posturography in 68% of patients, of whom 42% displayed a typical vestibular pattern. Remarkably, 90% revealed uni‐ or bilateral weak caloric responses, independent of caloric symmetry. Vestibular dysfunction is frequent in subjects with 22q11.2DS. This knowledge should be taken into account when assessing motor performance in these patients. Additional larger studies are needed to determine whether this dysfunction implicates a therapeutic potential.     

Expanding a common metric for depression reporting: linking two scales to PROMIS<Superscript>®</Superscript> depression

Purpose

Depression is a significant mental health concern. There are numerous depression questionnaires, several of which can be scored onto the Patient Reported Outcomes Measurement Information System (PROMIS^®) Depression metric. This study expands the unified metric by linking depression subscales from the Adult Self-Report (ASR) and the Brief Symptom Inventory (BSI) to it.

Methods

An online sample of 2009 men who have sex with men (MSM) was recruited. Item factor analysis was used to evaluate the dimensionality of the aggregated measures and confirm the statistical assumptions for linking. Then, linking was conducted using equipercentile and item response theory (IRT) methods. Equipercentile linking considered varying degrees of post-smoothing. IRT-based linking used fixed-anchor calibration and separate calibration with Stocking-Lord linking constants.

Results

All three scales were broadly unidimensional. This MSM sample had slightly higher average depression scores than the general population (mean = 54.4, SD = 9.6). Both linking methods provided robust, largely comparable results. Subgroup invariance held for age, race, and HIV status. Given the broad comparability across methods, the crosswalk between raw sum scores and the unified T-score metric used fixed-anchor IRT-based methods.

Conclusions

PROMIS provides a unified, interpretable metric for depression reporting. The results of this study allow the depression subscales from the ASR and BSI to be rescored onto the unified metric with reasonable caution. This will benefit epidemiological projects aggregating data across various measures or time points.

     

The role of governance in different types of interhospital collaborations: A systematic review

Context

Financial challenges and the need for high-quality care have vastly increased the number of hospital collaborations in recent decades. The governance of these collaborations remains a challenge. The goal of this study is twofold: (1) to investigate the governance characteristics in an interhospital collaboration and (2) explore the impact on the performance of the interhospital collaboration.

Associations Between Muscle Synergies and Treatment Outcomes in Cerebral Palsy Are Robust Across Clinical Centers

Objective

To determine whether patient-specific differences in motor control quantified using muscle synergy analysis were associated with changes in gait after treatment of cerebral palsy (CP) across 2 clinical centers with different treatments and clinical protocols.

Vibration-induced changes in EMG during human locomotion

The present study was set up to examine the contribution of Ia afferent input in the generation of electromyographic (EMG) activity. Subjects walked blindfolded along a walkway while tendon vibration was applied continuously to a leg muscle. The effects of vibration were measured on mean EMG activity in stance and swing phase. The results show that vibration of the quadriceps femoris (Q) at the knee and of biceps femoris (BF) at the knee enhanced the EMG activity of these muscles and this occurred mainly in the stance phase of walking. These results suggest involvement of Ia afferent input of Q and BF in EMG activation during stance. In contrast, vibration of muscles at the ankle and hip had no significant effect on burst amplitude. Additionally, the onset time of tibialis anterior was measured to look at timing of phase transitions. Only vibration of quadriceps femoris resulted in an earlier onset of tibialis anterior within the gait cycle, suggesting involvement of these Ia afferents in the triggering of phase transitions. In conclusion, the results of the present study suggest involvement of Ia afferent input in the control of muscle activity during locomotion in humans. A limited role in timing of phase transitions is proposed as well.     

Aetiology of congenital hearing loss: A cohort review of 569 subjects

Objective

Newborn hearing screening was implemented in Flanders about fifteen years ago. The aim of this study was to determine the aetiology of hearing loss detected by the Flemish screening programme.

Methods

From 1997 to 2011, 569 neonates were referred to our tertiary referral centre after failed neonatal screening with Auditory Brainstem Responses. In case hearing loss (HL) was confirmed, further diagnostic testing was launched. A retrospective chart review was performed analysing the degree of HL, risk factor and aetiology.

Results

Metabolic disorders (0.5%), infectious diseases (35.8%), congenital malformations (6.1%) and genetic abnormalities (19.8%), whether or not syndromic, were retained. In 35% of the subjects no obvious aetiology could be determined in the current study.

Conclusion

In contrast to the literature findings, this series shows a genetic syndromic cause in 80% of the genetic bilateral HL cases. On the other hand connexin positive diagnoses were mostly underrepresented in this study, showing the need for better screening.     

Probabilistic gait classification in children with cerebral palsy: a Bayesian approach

Three-dimensional gait analysis (3DGA) generates a wealth of highly variable data. Gait classifications help to reduce, simplify and interpret this vast amount of 3DGA data and thereby assist and facilitate clinical decision making in the treatment of CP. CP gait is often a mix of several clinically accepted distinct gait patterns. Therefore, there is a need for a classification which characterizes each CP gait by different degrees of membership for several gait patterns, which are considered by clinical experts to be highly relevant. In this respect, this paper introduces Bayesian networks (BN) as a new approach for classification of 3DGA data of the ankle and knee in children with CP. A BN is a probabilistic graphical model that represents a set of random variables and their conditional dependencies via a directed acyclic graph. Furthermore, they provide an explicit way of introducing clinical expertise as prior knowledge to guide the BN in its analysis of the data and the underlying clinically relevant relationships. BNs also enable to classify gait on a continuum of patterns, as their outcome consists of a set of probabilistic membership values for different clinically accepted patterns. A group of 139 patients with CP was recruited and divided into a training- (n = 80% of all patients) and a validation-dataset (n = 20% of all patients). An average classification accuracy of 88.4% was reached. The BN of this study achieved promising accuracy rates and was found to be successful for classifying ankle and knee joint motion on a continuum of different clinically relevant gait patterns.