Identifying and characterising sources of variability in digital outcome measures in Parkinson's disease

Smartphones and wearables are widely recognised as the foundation for novel Digital Health Technologies (DHTs) for the clinical assessment of Parkinson's disease. Yet, only limited progress has been made towards their regulatory acceptability as effective drug development tools. A key barrier in achieving this goal relates to the influence of a wide range of sources of variability (SoVs) introduced by measurement processes incorporating DHTs, on their ability to detect relevant changes to PD. This paper introduces a conceptual framework to assist clinical research teams investigating a specific Concept of Interest within a particular Context of Use, to identify, characterise, and when possible, mitigate the influence of SoVs. We illustrate how this conceptual framework can be applied in practice through specific examples, including two data-driven case studies.

A novel activated-zinc antiseptic solution effective against MRSA and Pseudomonas aeruginosa: a pig model

OBJECTIVE

The purpose of this study was to investigate the antimicrobial efficacy of a novel activated zinc solution against meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa after one hour, and to evaluate any untoward effect of the solution on local wound tissue at 24 hours after solution exposure in a pig wound model.

METHOD

A pathogen-free, commercially raised, Yorkshire-cross female pig was acquired 12 days prior to the procedure. Within one week prior to the procedure, a small loopful of test bacteria, Pseudomonas aeruginosa (pig-isolate) and MRSA (ATCC-6538), were streaked and cultured on a non-selective agar. Full-thickness wounds (n=24) were created and evenly divided into three groups: control wounds (exposed to bacteria but untreated, n=8); wounds treated with Compound 1 (n=8), and wounds treated with Compound 2 (n=8). All wounds were dressed and monitored for one hour and 24 hours.

RESULTS

After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable total bacteria of 2.8 log colony forming units (CFUs) and 3.5 logCFUs, respectively. After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable MRSA of 2.3 logCFUs and 1.6 logCFUs, respectively (p=0.009). After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable Pseudomonas aeruginosa of 0.3 logCFUs and 0.0 logCFUs, respectively (p=0.000). After 24 hours of exposure to Compound 1 and Compound 2, there was no statistically significant increased necrosis (p=0.12, p=0.31, respectively) or neutrophilic infiltrate (Compound 2, p=0.12) when compared with control wounds.

CONCLUSION

The novel activated-zinc compound used in this study demonstrated a 99.5-99.9% reduction in total bacteria, a 99.9-99.98% reduction in MRSA, and 100% eradication of Pseudomonas aeruginosa one hour after exposure. This novel solution may provide another significant tool to treat and/or prevent wound infections.

A Novel Activated Zinc Solution with Improved Efficacy Against Pseudomonas and MRSA Biofilm Compared to Chlorhexidine and Povidone-Iodine

INTRODUCTION

The search for the optimal agent for infection eradication in periprosthetic joint infection (PJI) remains challenging as there are limited efficacious and safe options. The ideal solution should have significant bactericidal and anti-biofilm activity to be able to eradicate infection with the preservation of prosthetic components. Therefore, the purpose of this study was to 1) investigate the anti-biofilm efficacy of a novel activated zinc solution against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) biofilm in vitro and 2) compare its efficacy against two leading commercially available antimicrobial irrigants (CHG and 0.35% povidone-iodine [PI]).

MATERIALS AND METHODS

A modified Robbins device (MRD) was utilized to replicate Pseudomonas aeruginosa and MRSA biofilms. The primary outcome was to determine bacterial reduction after two hours of biofilm exposure to an activated zinc solution, CHG, and PI, and compare to untreated controls.

RESULTS

Against Pseudomonas biofilm, activated zinc demonstrated a 4.5-log (99.996%) reduction, chlorhexidine demonstrated a 0.9-log (87.4%) reduction (p<0.001), and PI demonstrated a 0.8-log (83.1%) reduction (p<0.001). After two hours of exposure, activated zinc had undetectable MRSA with a 7.08-log (100%) reduction, chlorhexidine had a 1.9-log (98.7%) reduction (p<0.01), and PI had a 3.2-log (99.9%) reduction (p<0.01).

CONCLUSIONS

Our novel activated zinc compound demonstrated a 99.996% reduction in Pseudomonas biofilm and a 100% reduction in MRSA biofilm. This novel solution may provide a significant tool in the arsenal to treat and/or prevent PJI and other wound infections. Future in vivo studies are warranted to demonstrate clinical utility, efficacy, and safety.

Metadata Framework to Support Deployment of Digital Health Technologies in Clinical Trials in Parkinson's Disease

Sensor data from digital health technologies (DHTs) used in clinical trials provides a valuable source of information, because of the possibility to combine datasets from different studies, to combine it with other data types, and to reuse it multiple times for various purposes. To date, there exist no standards for capturing or storing DHT biosensor data applicable across modalities and disease areas, and which can also capture the clinical trial and environment-specific aspects, so-called metadata. In this perspectives paper, we propose a metadata framework that divides the DHT metadata into metadata that is independent of the therapeutic area or clinical trial design (concept of interest and context of use), and metadata that is dependent on these factors. We demonstrate how this framework can be applied to data collected with different types of DHTs deployed in the WATCH-PD clinical study of Parkinson's disease. This framework provides a means to pre-specify and therefore standardize aspects of the use of DHTs, promoting comparability of DHTs across future studies.

Myelination of the developing lateral olfactory tract and anterior commissure

Both the lateral olfactory tract (LOT) and anterior limb of the anterior commissure (AC) carry olfactory information. The LOT forms the projection from the olfactory bulb to the ipsilateral olfactory cortices, while the AC carries odor information across the midline to the contralateral olfactory cortex and bulb. The LOT and AC differ on a number of dimensions, including early development and functional onset. The present work, examining their myelination in mice, reveals additional important differences. For example, the LOT initiates myelination 3-4 days earlier than the AC, evidenced by both an earlier increase in myelin basic protein staining seen with immunohistochemistry and an earlier appearance of myelinated fibers using electron microscopy. While both exhibit a period of rapid myelination, it occurs 4-5 days earlier in the LOT than the AC. The tracts also respond differently to early sensory restriction. Unilateral naris occlusion from the day after birth to postnatal day 30 had no consistent effects on the AC but resulted in significantly thinner myelin sheaths relative to axon caliber in the LOT. Finally, the two tracts differ structurally (the LOT contains larger, more densely packed axons with significantly thicker myelin sheaths resulting in a conduction velocity that is more than twice as fast as the AC). The findings indicate that these two large, accessible tracts provide an important means for studying brain maturation due to basic differences in both the timing of their maturation and general organization.

Amyloid-β 11C-PiB-PET imaging results from 2 randomized bapineuzumab phase 3 AD trials

OBJECTIVE

To evaluate the effects of bapineuzumab on brain β-amyloid (Aβ) burden using (11)C-Pittsburgh compound B ((11)C-PiB)-PET.

METHODS

Two phase 3 clinical trials, 1 each in apolipoprotein APOE ε4 carriers and noncarriers, were conducted in patients with mild to moderate Alzheimer disease dementia. Bapineuzumab, an anti-Aβ monoclonal antibody, or placebo, was administered by IV infusion every 13 weeks for 78 weeks. PET substudies assessed change in brain fibrillar Aβ over 71 weeks using an (11)C-PiB-PET standardized uptake value ratio (SUVr) global cortical average (GCA) comprising the average SUVr from 5 cortical regions of interest with cerebellar gray matter as the reference region.

RESULTS

A total of 115 carriers and 39 noncarriers were analyzed. The difference (δ) in mean baseline to 71 week change in (11)C-PiB-PET GCA between bapineuzumab and placebo was significant in carriers (0.5 mg/kg vs placebo δ = -0.101; p = 0.004) and in pooled analyses of both carriers and noncarriers (0.5 mg/kg vs placebo δ = -0.068; p = 0.027; 1.0 mg/kg vs placebo δ = -0.133; p = 0.028) but not in the noncarrier trial separately. Analyses by individual region of interest and in mild disease yielded findings similar to the main trial results.

CONCLUSIONS

The (11)C-PiB-PET imaging results demonstrated reduction of fibrillar Aβ accumulation in patients with Alzheimer disease treated with bapineuzumab; however, as no clinical benefit was observed, the findings are consistent with the hypotheses that bapineuzumab may not have been initiated early enough in the disease course, the doses were insufficient, or the most critical Aβ species were inadequately targeted.

Identifying the best surface topography parameters for detecting idiopathic scoliosis curve progression

There is no consensus on which surface topography (ST) parameters may be used to detect scoliosis progression. The sensitivity to change of common ST parameters has not yet been compared. The goal of this study was to determine which ST parameters are most sensitive to scoliosis progression in patients with adolescent idiopathic scoliosis (AIS) receiving conservative treatment. Fifty-eight subjects with AIS were included whose Cobb angle had progressed by at least 5 degrees during a 1 year interval. All had had ST scans and frontal radiographs at a 12 month interval at our clinic. Commonly used back-only ST parameters and contributing scores were derived by one evaluator. Standardized response mean (SRM) and 95% confidence intervals (CI) were calculated using the absolute value of the changes between baseline and follow-up to reflect change in deformity, independent of direction. Decompensation, cosmetic score, Deformity in the Axial Plane Index (DAPI), trunk rotation, Hump Sum, and lordosis angle were highly sensitive to scoliosis progression (SRM>0.8). Cosmetic score, Posterior Trunk Symmetry Index (POTSI), and kyphosis angle had significantly poorer SRM values than the Cobb angle. All other ST parameters had SRM estimates that did not differ significantly from the Cobb angle, suggesting that they have a similar ability to detect progression The ST measures that were most sensitive to detection of scoliosis progression in the frontal, transverse, and sagittal planes were decompensation, trunk rotation, and lordosis angle, respectively. Absolute changes in surface parameters representing either worsening or improvement externally could reflect worsening of the internal deformity. The majority of ST parameters are potentially sensitive to scoliosis progression.

Publication rate of abstracts presented at the shoulder and elbow session of the American Academy of Orthopaedic Surgery

Many shoulder and elbow abstracts presented at the American Academy of Orthopaedic Surgeons (AAOS) annual meeting are cited in the orthopaedic literature or are used to guide orthopaedic practice, but not all of these abstracts are submitted, survive peer review, or eventually are published. Presuming unpublished works have not been scientifically confirmed, one could question whether it is academically responsible to cite abstracts presented at the AAOS before they are peer-reviewed and published. To partly address this issue we determined the peer-reviewed publication rate for 558 abstracts (233 papers and 325 posters) presented at the shoulder and elbow sessions of the AAOS from 1999 to 2004. In April 2007, we searched the computerized database MEDLINE and PubMed for published articles based on these abstracts. We examined the published articles to assess publication rate, time to publication, change in contents, change in authors, and change in conclusions of abstracts. The overall publication rate in peer-reviewed journals was 58% (321 of 558), similar to other orthopaedic meetings and medical disciplines. We believe it is unacceptable to cite shoulder and elbow abstracts submitted to the AAOS because only slightly more than (1/2) (58%) of them are authenticated scientifically.

The effects of dietary protein restriction on chorda tympani nerve taste responses and terminal field organization

Prenatal dietary sodium restriction produces profound developmental effects on rat functional taste responses and formation of neural circuits in the brainstem. Converging evidence indicates that the underlying mechanisms for these effects are related to a compromised nutritional state and not to direct stimulus-receptor interactions. We explored whether early malnourishment produces similar functional and structural effects to those seen following dietary sodium restriction by using a protein deficient, sodium replete diet. To determine if early dietary protein-restriction affects the development of the peripheral gustatory system, multi-fiber neurophysiological recordings were made from the chorda tympani nerve and anterograde track tracing of the chorda tympani nerve into the nucleus of the solitary tract (NTS) was accomplished in rats fed a protein-restricted or a control diet (6% and 20%, respectively). The dietary regimens began on embryonic day 7 and continued until rats were used for neurophysiological recordings (postnatal days (P) 35-50) or for chorda tympani terminal field labeling (P40-50). Responses to a concentration series of NaCl, sodium acetate, KCl, and to 0.50 M sucrose, 0.03 M quinine-HCl, and 0.01 N HCl revealed attenuated responses (30-60%) to sodium-specific stimuli in rats fed the 6% protein diet compared with those fed the 20% protein diet. Responses to all other stimuli were similar between groups. Terminal field volumes were nearly twofold larger in protein-restricted rats compared with controls, with the differences located primarily in the dorsal-caudal zone of the terminal field. These results are similar to the results seen previously in rats fed a sodium-restricted diet throughout pre- and postnatal development, suggesting that dietary sodium- and protein-restriction share similar mechanisms in altering gustatory development.

Smart garment to help children improve posture

Many of the aches and pains of adults are the result not of injuries, but of the long-term effects of distortions in posture or alignment. Postural kyphosis in adolescence may be one of the effects of poor standing and sitting habits. Kyphosis is an excessive rounding of the upper spine. A smart garment that can monitor and provide vibration feedback to children has been developed to investigate an alternative treatment possibility. Laboratory tests verified that the accuracy of the system was +/-2 degrees within the full 180 degrees range. A clinical trial has been conducted and it showed that the system can aid subjects to improve by 20% the proportion of time in a more balanced posture. The long term effect is still under investigation.

20(S)-25-methoxyl-dammarane-3beta, 12beta, 20-triol, a novel natural product for prostate cancer therapy: activity in vitro and in vivo and mechanisms of action

We recently isolated 20(S)-25-methoxyl-dammarane-3β, 12β, 20-triol (25-OCH₃-PPD), a natural product from Panax notoginseng, and demonstrated its cytotoxicity against a variety of cancer cells. Here we report the effects of this compound in vitro and in vivo on human prostate cancer cells, LNCaP (androgen-dependent) and PC3 (androgen-independent), in comparison with three structurally related ginsenosides, ginsenoside Rh2, ginsenoside Rg3, and 20(S)-protopanaxadiol. Of the four test compounds, 25-OCH₃-PPD was most potent. It decreased survival, inhibited proliferation, induced apoptosis, and led to G1 cell cycle arrest in both cell lines. It also decreased the levels of proteins associated with cell proliferation (MDM2, E2F1, cyclin D1, and cdks 2 and 4) and increased or activated pro-apoptotic proteins (cleaved PARP, cleaved caspase-3, -8, and -9). In LNCaP cells, 25-OCH₃-PPD inhibited the expression of the androgen receptor and prostate-specific antigen. Moreover, 25-OCH₃-PPD inhibited the growth of prostate cancer xenograft tumours. Combining 25-OCH₃-PPD with conventional chemotherapeutic agents or with radiation led to potent antitumour effects; tumour regression was almost complete following administration of 25-OCH₃-PPD and either taxotere or gemcitabine. 25-OCH₃-PPD also demonstrated low toxicity to noncancer cells and no observable toxicity in animals. In conclusion, our preclinical data indicate that 25-OCH₃-PPD is a potential therapeutic agent against both androgen-dependent and androgen-independent prostate cancer.

A wireless personal wearable network system to understand the biomechanics of orthotic for the treatment of scoliosis

The wear tightness of an orthosis for the treatment of scoliosis varies greatly during daily activities. Currently, there is no commercially available product that can monitor force distribution inside the brace and the time that the othosis is worn during daily activities. Subjective feeling is the most commonly used method. To provide an objective measure, a battery-powered wireless personal wearable network system is developed. This system consists of up to 16 wireless force loggers and a USB ZigBee dongle. Each logger contains a force sensor and a wireless unit. The whole system records how much time the orthosis has been used and how loads distribute inside the orthoses. Laboratory tests have been performed; the maximum force measurement error is +/-0.02N and the resolution is 0.1N. The average power consumption of the system is 0.3mW/h and thus a single AAA-sized alkaline battery is able to support the power for 6 months.

Isolation, structural determination, and evaluation of the biological activity of 20(S)-25-methoxyl-dammarane-3beta, 12beta, 20-triol [20(S)-25-OCH3-PPD], a novel natural product from Panax notoginseng

Ginseng has been used extensively for medicinal purposes, with suggested utility for indications as diverse as diabetes, cardiovascular disease and cancer. Herein we report the discovery and characterization of 20(S)-25-OCH3-PPD, a ginsenoside that inhibits growth and survival of cancer cells. The novel dammarane triterpene sapogenin (C31H56O4; molecular weight 492) was isolated from the total hydrolyzed saponins extracted from the leaves of Panax notoginseng using conventional and reverse-phase silica gel chromatography. Based on physicochemical characteristics and NMR data, the compound was identified as 20(S)-25-OCH3-PPD. The biological activities of 20(S)-25-OCH3-PPD and its known analogs, 20(S)-PPD and Rg3, were evaluated in 12 human cancer cell lines. In all cell lines, the order of cytotoxicity of the test compounds was 20(S)-25-OCH3-PPD >> 20(S)-PPD >> Rg3. 20(S)-25-OCH3-PPD also induced apoptosis and cell cycle arrest in the G1 phase, and inhibited proliferation in breast cancer cell lines, demonstrating its potent biological effects. In regard to cytotoxicity, the IC50 values of 20(S)-25-OCH3-PPD for most cell lines were in the lower microM range, a 5-15-fold greater cytotoxicity relative to 20(S)-PPD and a 10-100-fold increase over Rg3. These findings suggest a structure-activity relationship among dammarane-type sapogenins. The data presented here may provide a basis for the future development of 20(S)-25-OCH3-PPD as a novel anti-cancer agent.

Ribosomal protein S7 as a novel modulator of p53-MDM2 interaction: binding to MDM2, stabilization of p53 protein, and activation of p53 function

As a major negative regulator of p53, the MDM2 oncogene plays an important role in carcinogenesis and tumor progression. MDM2 promotes p53 proteasomal degradation and negatively regulates p53 function. The mechanisms by which the MDM2-p53 interaction is regulated are not fully understood, although several MDM2-interacting molecules have recently been identified. To search for novel MDM2-binding partners, we screened a human prostate cDNA library by the yeast two-hybrid assay using full-length MDM2 protein as the bait. Among the candidate proteins, ribosomal protein S7 was identified and confirmed as a novel MDM2-interacting protein. Herein, we demonstrate that S7 binds to MDM2, in vitro and in vivo, and that the interaction between MDM2 and S7 leads to modulation of MDM2-p53 binding by forming a ternary complex among MDM2, p53 and S7. This results in the stabilization of p53 protein through abrogation of MDM2-mediated p53 ubiquitination. Consequently, S7 overexpression increases p53 transactivational activities, induces apoptosis, and inhibits cell proliferation. The identification of S7 as a novel MDM2-interacting partner contributes to elucidation of the complex regulation of the MDM2-p53 interaction and has implications in cancer prevention and therapy.

Smart orthosis for the treatment of adolescent idiopathic scoliosis

There is considerable controversy regarding the effectiveness of orthotic treatment for patients with adolescent idiopathic scoliosis. Most researchers believe that, to be effective, the orthosis must be worn as prescribed for both compliance and tightness. Compliance is the time the brace is worn relative to the prescribed time. A battery-powered microcomputer system was developed to monitor and maintain the loads exerted by orthoses used to treat children with spinal deformities during daily living. This system not only records how well and for how much time the brace has been used, but also helps patients to ensure that the brace is being worn at the prescribed tightness. Laboratory tests were performed, and five patients used the system for four weeks. The patients reported that the system helped them to wear the orthoses correctly and comfortably. The time that the patients wore the orthoses at the prescribed tightness level increased from 53 +/- 9% during the monitoring period (first 2 weeks) to 68 +/- 14% during the automatic adjustment period (last 2 weeks).

Catheter tracking and visualization using 19F nuclear magnetic resonance

This work presents an investigation into catheter visualization and localization using 19F nuclear magnetic resonance (NMR) in conjunction with proton imaging. For this purpose, the imaging capabilities of a standard system were extended to allow for 19F excitation and signal detection. Two modes of operation were implemented: 1) a real-time tracking mode that provides tip tracking and automatic slice position updates interleaved with real-time, interactive proton imaging; and 2) a non-real-time catheter length visualization mode in which the entire length of a catheter can be assessed. Initial phantom experiments were conducted with the use of an angiographic balloon catheter filled with the blood substitute perfluorooctylbromide (PFOB). Using limited bandwidth excitation centered at the resonances of the CF2 groups of PFOB, we found that sufficient signal could be received to facilitate tip tracking during catheter motion and length visualization for various catheter configurations. The present approach is considered a promising alternative to existing methods, which either are associated with safety concerns (if active markers are employed) or suffer from insufficient, direction-dependent contrast (if passive visualization is used). Furthermore, our approach enables visualization of the entire length of the catheter. The proposed method provides a safe technique that, unlike electrical or optical devices, does not require modification of commercially available catheters.

Correlation between quantity and quality of orthosis wear and treatment outcomes in adolescent idiopathic scoliosis

Orthotic treatment is the most commonly used non-surgical treatment method for adolescent idiopathic scoliosis (AIS). This study determined whether treatment outcome correlates with how often and how well children with AIS wear their orthoses. Eighteen (18) subjects (3M, 15F) who were diagnosed with idiopathic scoliosis and had worn their orthoses from 6 months up to 1 year participated in this study. All subjects were prescribed Boston braces to be worn full time (23 hrs/day). Twelve (12) subjects who completed their brace treatment were included in the data analysis. Three (3) treatment outcomes were classified as improvement, no change and deterioration. The quality of the brace wear was assessed by how often the brace was worn with zero force, below 80%, between 80 to 120%, and above 120% of the load level prescribed in the clinic. The quantity of brace wear was determined by how many hours per day they wore their brace. Subjects who wear their braces tighter and for more hours per day seem to have better outcomes.

Bluetooth wireless database for scoliosis clinics

A database system with Bluetooth wireless connectivity has been developed so that scoliosis clinics can be run more efficiently and data can be mined for research studies without significant increases in equipment cost. The wireless database system consists of a Bluetooth-enabled laptop or PC and a Bluetooth-enabled handheld personal data assistant (PDA). Each patient has a profile in the database, which has all of his or her clinical history. Immediately prior to the examination, the orthopaedic surgeon selects a patient's profile from the database and uploads that data to the PDA over a Bluetooth wireless connection. The surgeon can view the entire clinical history of the patient while in the examination room and, at the same time, enter in any new measurements and comments from the current examination. After seeing the patient, the surgeon synchronises the newly entered information with the database wirelessly and prints a record for the chart. This combination of the database and the PDA both improves efficiency and accuracy and can save significant time, as there is less duplication of work, and no dictation is required. The equipment required to implement this solution is a Bluetooth-enabled PDA and a Bluetooth wireless transceiver for the PC or laptop.

Instrumented rod rotator system for spinal surgery

An electronically instrumented rod rotator has been developed to monitor forces and moments applied by surgeons during the derotation manoeuver to correct spinal curvature. This instrumented rod rotator consisted of an inclinometer and two pairs of strain gauges, with all the support circuitry. The strain gauge and the inclinometer data were sampled with a data-acquisition system, and the results were displayed in real time. The device was calibrated in the laboratory and used on seven subjects. The precision of the load measurement of this device was +/- 5 N in the range of 5-65N. The distance between the middle of the rod rotator handle to the rod position was 0.21 m. The maximum loads applied by the surgeon during seven surgeries were from 22 to 57N, with a torque (force x distance) from 4.6 to 12 Nm.

Using three-dimensional difference maps to assess changes in scoliotic deformities

The three-dimensional nature of scoliosis, coupled with changes due to natural history or treatment, is often difficult to quantify and visualise. A difference map was developed to compare the sequential surface topography of subjects over their treatment period. Three-dimensional surface maps representing patients' trunk surfaces were captured with a laser scanner. Patient surface maps from two clinic visits were matched using a manual best-fit technique that accounted for growth and positioning. The surfaces were subtracted, generating a colour-coded three-dimensional difference map displaying the surface changes. The difference maps were compared with known clinical measures, indicating good agreement (78% specific) with the clinical parameters in detecting change. Full agreement or agreement with the clinical parameters occurred in the surgical, brace and no treatment groups: 76%, 80% and 85%, respectively. A difference index (average of the absolute value of differences on a point-by-point basis) was calculated from the difference map, enabling quantification of change. The difference index, with zero being a perfect match, averaged 5 +/- 1 for repeated measures 7 +/- 2 for subjects deemed to have no change, 9 +/- 2 for subjects with slight change, and 14 +/- 2 for subjects with significant change. The difference map showed the extent and location of changes and is a useful tool for assessing surface topography changes.

The daily force pattern of spinal orthoses in subjects with adolescent idiopathic scoliosis

The efficacy of orthotic treatment for children with abnormal spinal curvature has been hampered by the lack of comprehensive information about wear characteristics. A battery-powered microcomputer system was developed to monitor loads exerted by orthoses used to treat children with spinal deformities during daily living. The system not only records how well the orthosis has been used, but also helps to ensure that the orthosis is being worn as prescribed. Data acquisition is controlled by a microcontroller and can be programmed to have sample intervals ranging from 1 second to 1 hour. Low power control circuitry is designed so that the system can be operated by a battery. In a preliminary study, 16 subjects (3M, 13F) used this system from 1 to 16 days (9.3 +/- 5.0) with the prescribed hours between 16 to 23 hours (22.3 +/- 1.3). This study demonstrated the feasibility of the approach, and that this device may increase the understanding of orthotic mechanics, and may help patients to wear their orthoses in a better way.

Evaluation of a laser scanner for surface topography

A Minolta VIVID 700 portable non-contact 3D laser scanner was evaluated on 15 subjects with idiopathic scoliosis. The 3D map was compared to two structured light pattern (lines and dots) techniques to determine the reliability, ease of use, speed, and quality. The parameters used for the clinical assessment of scoliosis were measured twice for the Minolta and light projection systems. The edges of the image and areas where occlusion typically occur were examined. The absolute distance in calculated depth between adjacent points was examined to determine errors. The Minolta system and the dot pattern produced regular grids of points. The light projection pattern produced an irregular grid, with more resolution along the video line and less resolution between projected lines, resulted in a somewhat jagged appearance of the surface map. The Minolta system was less sensitive to edge effects, occlusion, and sharp transitions of depth. The comparison of clinical parameters showed good results between repetitions but moderate results between techniques.

Local energy as a measure of back symmetry in scoliosis

The Cobb angle has been the most commonly used method in measuring the severity of scoliosis and its progression. However, in recent years a number of researchers have chosen to monitor scoliosis by examining the severity of the surface deformity resulting from the scoliosis. Each of these approaches has been limited by errors introduced in manual location of landmarks. Scoliosis results in an asymmetry of the back. It would be very desirable to have a computer-based method of measuring this asymmetry. This paper investigates the use of wavelets and the concept of local energy to measure asymmetry associated with scoliosis. The local energy model uses wavelet theory to obtain information about shading and boundaries of objects in an image. Edges and sharp discontinuities are areas of high local energy in an image. Features such as scapular prominence, shoulder edges, waist creases and other anomalies that contribute to the scoliotic back asymmetry have high local energy. A preliminary study was completed to determine if this approach was applicable to measurement of back asymmetry. Two-dimensional local energy images were created from photographs of the backs of patients with scoliosis. The local energy was integrated across each image and a left-to right line of symmetry was calculated. This line of symmetry was then correlated with the scoliotic score developed by our group. This technique shows promise of providing an automatic method of measuring scoliosis progression.

Image coding technique for 3-D back reconstruction

This work investigated the use of coded-line patterns to improve image correspondence and 3D reconstruction. The objective was to define an optimum structured light pattern to facilitate the construction of topographic maps of the trunks of scoliosis patients. The system consisted of stereo CCD television cameras, a slide projector to create the coded-line pattern and a computer with video acquisition card. The optimum pattern in terms of generating correct results with minimum computing time was a line pattern consisting of 6 groupings of 3-level grey lines. This chosen pattern was investigated using known 3D objects to determine the effectiveness, resolution and computational time to correlate stereo images. The selected structured light pattern consisted of a repeated pattern of white (W), grey (G) and black (B) lines. Each line was 4mm wide on the back surface. The pattern consisted of 6 groups of 3 lines, WBG WGB GWB GBW BGW BWG. Using known 3D models of a section of a cylinder, a plate with steps and a ramp-like object; the coded line system was tested under typical clinical lighting conditions. For the 3D test objects, errors in correspondence occurred in 2-4 % of stereo pixels. The processing time varied from 10-12 minutes. The 3D resolution obtained was 4mm.

Computer modelling of hooks for use as intra-operative force sensors

There are a number of forces applied during scoliosis surgery, the magnitude and direction of which remains unknown. There is little literature concerning the in vivo distribution of forces along the spine. Computer modelling (ANSYS) was used to investigate the possibility of using an instrumented hook to intra-operatively measure the antero-posterior and distraction/compression forces applied by the surgeon during corrective scoliosis surgery. Three hook designs were evaluated based on specific design criteria. ANSYS provided the preliminary analysis to determine the strain distribution in these hooks. One design, the "membrane" design, was selected and a prototype was manufactured. Preliminary tests demonstrate that this prototype will be able to differentiate between the four major forces applied during the surgical correction.

Assessing changes in three dimensional scoliotic deformities with difference maps

Topographical difference maps were used to compare the trunk surfaces of subjects over the course of their treatment. Three-dimensional points representing the trunk surfaces were aligned accounting for growth and positioning. A goodness-of-fit score was calculated and a color map used to display trunk surface changes. Fifty-one successive subjects were assessed with difference maps. Two subjects each had 10 repetitions taken on the same day to assess reliability. A blinded observer used a five-point scale that extended from full agreement to full disagrment to judge the maps according to the extent and location of changes. The observations were compared to clinical measures mapped onto the same scale by another blinded observer. Goodness of fit for repeated measures averaged 5 +/- 1, for subjects deemed to have no change 7 +/- 2, for subjects with slight change 9 +/- 2, and 14 +/- 2 for subjects with significant change. Judges were in full agreement or in agreemnt with forty of the fifty-one subjects (78%) and in slight disagreement with the remaining eleven. When the cohort was subdivided in surgical, brace and no treatment groups, the judges were in full agreement or in agreement 76%, 80%, and 85% respectively. The difference map provides a qualitative and quantitative measure of how the trunk surface has changed as a whole.

Is the Boston brace mechanically effective in AIS?

The application of three-point loading is thought to be the essential basis for effective bracing of adolescent idiopathic scoliosis. Care is taken to ensure that active pressure pad is located to provide maximum support to the apex of the scoliosis while minimizing its lordosising effect. Paradoxically, while cited as an essential factor in the design of braces, there is no consensus as to the importance of such loading to the clinical effectiveness of braces. It may be that braces are effective but that they are effective for reasons unrelated to mechanics. There are few studies that link brace mechanics and change in spinal alignment. Optimal bracing for AIS requires a much better understanding of the role of the mechanical support of braces used to treat AIS. Sixteen subjects, 3 males and 13 females, were participated to this study to determine the correlation between quantity and quality of brace wear and treatment outcomes in AIS. This study showed that the target force levels set for the active pad in braces prescribed for the treatment of AIS vary considerably and that brace applies the desired load 25% of the prescribed time.

Validation of a two- to three-dimensional registration algorithm for aligning preoperative CT images and intraoperative fluoroscopy images

We present a validation of an intensity based two- to three-dimensional image registration algorithm. The algorithm can register a CT volume to a single-plane fluoroscopy image. Four routinely acquired clinical data sets from patients who underwent endovascular treatment for an abdominal aortic aneurysm were used. Each data set was comprised of two intraoperative fluoroscopy images and a preoperative CT image. Regions of interest (ROI) were drawn around each vertebra in the CT and fluoroscopy images. Each CT image ROI was individually registered to the corresponding ROI in the fluoroscopy images. A cross validation approach was used to obtain a measure of registration consistency. Spinal movement between the preoperative and intraoperative scene was accounted for by using two fluoroscopy images. The consistency and robustness of the algorithm when using two similarity measures, pattern intensity and gradient difference, was investigated. Both similarity measures produced similar results. The consistency values were rotational errors below 0.74 degree and in-plane translational errors below 0.90 mm. These errors approximately relate to a two-dimensional projection error of 1.3 mm. The failure rate was less than 8.3% for three of the four data sets. However, for one of the data sets a much larger failure rate (28.5%) occurred.

Community interdisciplinary education to promote partnerships in family violence prevention

Family violence is a major social and health problem in the United States. Educational approaches are needed that help professionals and communities develop more effective skills to work with families and communities. This article describes a statewide, interdisciplinary, community-based educational program for professionals and paraprofessionals and a 6-month post-evaluation. Participants reported knowledge and skill development in assessment and interventions, improved use of violence prevention data for planning and interventions, and increased community partnerships and collaborations. Recommendations address violence prevention leadership, funding, infrastructure, interdisciplinary professional education, greater community awareness, and policy development.

Stereo augmented reality in the surgical microscope

We present an augmented reality system that allows surgeons to view features from preoperative radiological images accurately overlaid in stereo in the optical path of a surgical microscope. The purpose of the system is to show the surgeon structures beneath the viewed surface in the correct 3-D position. The technical challenges are registration, tracking, calibration and visualisation. For patient registration, or alignment to preoperative images, we use bone-implanted markers and a dental splint is used for patient tracking. Both microscope and patient are tracked by an optical localiser. Calibration uses an accurately manufactured object with high contrast circular markers which are identified automatically. All ten camera parameters are modelled as a bivariate polynomial function of zoom and focus. The overall system has a theoretical overlay accuracy of better than 1 mm. Implementations of the system have been tested on seven patients. Recent measurements in the operating room conformed to our accuracy predictions. For visualisation the system has been implemented on a graphics workstation to enable high frame rates with a variety of rendering schemes. Several issues of 3-D depth perception remain unsolved, but early results suggest that perception of structures in the correct 3-D position beneath the viewed surface is possible.