Automated Detection of Real-World Falls: Modeled From People With Multiple Sclerosis.

Falls are a major health problem with one in three people over the age of 65 falling each year, oftentimes causing hip fractures, disability, reduced mobility, hospitalization and death. A major limitation in fall detection algorithm development is an absence of real-world falls data. Fall detection algorithms are typically trained on simulated fall data that contain a well-balanced number of examples of falls and activities of daily living. However, real-world falls occur infrequently, making them difficult to capture and causing severe data imbalance. People with multiple sclerosis (MS) fall frequently, and their risk of falling increases with disease progression. Because of their high fall incidence, people with MS provide an ideal model for studying falls. This paper describes the development of a context-aware fall detection system based on inertial sensors and time of flight sensors that is robust to imbalance, which is trained and evaluated on real-world falls in people with MS. The algorithm uses an auto-encoder that detects fall candidates using reconstruction error of accelerometer signals followed by a hyper-ensemble of balanced random forests trained using both acceleration and movement features. On a clinical dataset obtained from 25 people with MS monitored over eight weeks during free-living conditions, 54 falls were observed and our system achieved a sensitivity of 92.14%, and false-positive rate of 0.65 false alarms per day.

Design and Evaluation of a Non-ContactBed-Mounted Sensing Device for AutomatedIn-Home Detection of Obstructive Sleep Apnea:A Pilot Study.

We conducted a pilot study to evaluate the accuracy of a custom built non-contactpressure-sensitive device in diagnosing obstructive sleep apnea (OSA) severity as an alternative toin-laboratory polysomnography (PSG) and a Type 3 in-home sleep apnea test (HSAT). Fourteenpatients completed PSG sleep studies for one night with simultaneous recording from ourload-cell-based sensing device in the bed. Subjects subsequently installed pressure sensors in theirbed at home and recorded signals for up to four nights. Machine learning models were optimized toclassify sleep apnea severity using a standardized American Academy of Sleep Medicine (AASM)scoring of the gold standard studies as reference. On a per-night basis, our model reached a correctOSA detection rate of 82.9% (sensitivity = 88.9%, specificity = 76.5%), and OSA severity classificationaccuracy of 74.3% (61.5% and 81.8% correctly classified in-clinic and in-home tests, respectively).There was no difference in Apnea Hypopnea Index (AHI) estimation when subjects wore HSATsensors versus load cells (LCs) only (p-value = 0.62). Our in-home diagnostic system providesan unobtrusive method for detecting OSA with high sensitivity and may potentially be used forlong-term monitoring of breathing during sleep. Further research is needed to address the lowerspecificity resulting from using the highest AHI from repeated samples.

Design and evaluation of a portable smart-phone based peripheral neuropathy test platform.

In this paper, we describe a novel portable test platform that can be used to test peripheral neuropathy either within a clinic or at home. The system, called the PeriVib, is comprised of (1) a small, custom vibration motor designed to apply a vibration stimulus to the toe with constant pressure to test sensation threshold, and (2) a custom smart-phone app that enables a patient to run a series of functional gait and balance tests. Vibration is applied by PeriVib in two separate modes. The first mode, ramp-up, starts at zero amplitude and increases to a maximum level while the patient indicates when they start feeling the pressure by lifting their finger off the touch-screen on the phone. The second mode, ramp-down, starts at a maximal intensity and decreases in intensity; the patient indicates when they stop feeling the vibration. The smart-phone app determines the patient's threshold by recording the vibration amplitude when they indicate the onset or loss of vibratory sensation, depending on the mode. In both modes, the measurement is repeated five times. In addition to controlling the vibration motor during the vibration test, the smart phone app also enables collection of gait and sway metrics through the use of the accelerometer and gyroscope sensors on the smartphone. The entire set of tests requires approximately 5 minutes to complete and can be done by a patient with minimal instructions from a clinician. In a cohort of 28 subjects with a history of chemotherapy-induced peripheral neuropathy, we compared the PeriVib performance with two established threshold sensing systems: (1) a Biothesiometer device and (2) a tuning fork. We found that the sensation threshold estimated by PeriVib correlated well with the Biothesiometer ($\mathrm{R}^{2}$ of 0.68) but less well with the tuning fork ($\mathrm{R}^{2}$ of 0.15). Functional gait and balance metrics did not correlate with peripheral neuropathy severity.

Randomized Outpatient Trial of Single- and Dual-Hormone Closed-Loop Systems That Adapt to Exercise Using Wearable Sensors.

OBJECTIVE: Automated insulin delivery is the new standard for type 1 diabetes, but exercise-related hypoglycemia remains a challenge. Our aim was to determine whether a dual-hormone closed-loop system using wearable sensors to detect exercise and adjust dosing to reduce exercise-related hypoglycemia would outperform other forms of closed-loop and open-loop therapy. RESEARCH DESIGN AND METHODS: Participants underwent four arms in randomized order: dual-hormone, single-hormone, predictive low glucose suspend, and continuation of current care over 4 outpatient days. Each arm included three moderate-intensity aerobic exercise sessions. The two primary outcomes were percentage of time in hypoglycemia (<70 mg/dL) and in a target range (70-180 mg/dL) assessed across the entire study and from the start of the in-clinic exercise until the next meal. RESULTS: The analysis included 20 adults with type 1 diabetes who completed all arms. The mean time (SD) in hypoglycemia was the lowest with dual-hormone during the exercise period: 3.4% (4.5) vs. 8.3% (12.6) single-hormone (P = 0.009) vs. 7.6% (8.0) predictive low glucose suspend (P < 0.001) vs. 4.3% (6.8) current care where pre-exercise insulin adjustments were allowed (P = 0.49). Time in hypoglycemia was also the lowest with dual-hormone during the entire 4-day study: 1.3% (1.0) vs. 2.8% (1.7) single-hormone (P < 0.001) vs. 2.0% (1.5) predictive low glucose suspend (P = 0.04) vs. 3.1% (3.2) current care (P = 0.007). Time in range during the entire study was the highest with single-hormone: 74.3% (8.0) vs. 72.0% (10.8) dual-hormone (P = 0.44). CONCLUSIONS: The addition of glucagon delivery to a closed-loop system with automated exercise detection reduces hypoglycemia in physically active adults with type 1 diabetes.

Expanding the net: The re-evaluation of the multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) in the setting of secondary hyperparathyroidism and the development of the MultIdimensional Predictive hyperparaTHyroid model (Mi-PTH).

BACKGROUND: The multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) model identifies a personalized upper limit of normal parathyroid hormone (PTH) and successfully predicts classical primary hyperparathyroidism (PHP). We aimed to assess whether maxPTH can distinguish normocalcemic PHP (NCPHP) from secondary hyperparathyroidism (SHP), including subjects who underwent bariatric surgery (BrS). METHODS: A total of 172 subjects with 359 complete datasets of serum calcium (Ca), 25-OH vitamin D, and intact PTH from Oregon were analyzed: 123 subjects (212 datasets) with PHP and 47 (143) with SHP, including 28 (100) with previous BrS. An improved prediction model, MultIdimensional evaluation for Primary hyperparaTHyroidism (Mi-PTH), was created with the same variables as maxPTH by the use of a combined cohort (995 subjects) including participants from previous studies. RESULTS: In the Oregon cohort, maxPTH's sensitivity was 100% for classical PHP and 89% for NCPHP, but only 50% for normohormonal PHP (NHPHP) and 40% specific for SHP. In comparison, although sensitivity for NCPHP was similar (89%), Mi-PTH vastly improved SHP specificity (85%). In the combined cohort, Mi-PTH had better sensitivity of 98.5% (vs 95%) and specificity 97% (vs 85%). CONCLUSION: MaxPTH was sensitive in detecting PHP; however, there was low specificity for SHP, especially in patients who underwent BrS. The creation of Mi-PTH provided improved performance measures but requires further prospective evaluation.

Medical therapy for advanced forms of thyroid cancer.

More options than ever before are currently available for medical therapy in patients who present with advanced thyroid cancer or develop surgically unresectable recurrences or symptomatic or progressive disease. The newer medical therapies have addressed the need to find effective therapies beyond the conventional treatment with radioactive iodine, thyroid stimulating hormone suppression, and palliative cytotoxic chemotherapy for patients with advanced thyroid cancer. Although tumor responses to these medical therapies vary by type of thyroid cancer and type of therapy selected, they remain encouraging and provide therapeutic options for selected patients while new drugs are in development.

Plug the leak: align public spending with public need.

We explore the history behind the current structure of graduate medical education funding and the problems with continuing along the current funding path. We then offer suggestions for change that could potentially manage this health care spill. Some of these changes include attracting more students into primary care, aligning federal graduate medical education spending with future workforce needs, and training physicians with skills they will require to practice in systems of the future.

Persistent noncompliance with the work-hour regulation.

OBJECTIVE: To investigate the reason for noncompliance with the work-hour regulation by surgical residents. DESIGN: Nationwide anonymous survey (November 1, 2007, to March 1, 2008). SETTING: Academic center. PARTICIPANTS: Surgical residents throughout the United States. MAIN OUTCOME MEASURES: Incidence of noncompliance remains high and reasons for noncompliance are multifactorial. RESULTS: The first 141 questionnaires returned were included in this analysis. Responders consisted of postgraduate year (PGY)-1 (32.6%), PGY-2 (19.1%), PGY-3 (17.7%), PGY-4 (13.5%), and PGY-5 (17.0%) surgical residents. Many residents were categorical (79.4%), male (61.7%), and married (53.2%). Ninety-eight percent of residents were aware of the work-hour regulation, with 72.1% of residents in favor of it. However, noncompliance with the work-hour regulation was 64.6%, with 21.1% of residents working more than 90 h/wk (average, 86.6 h/wk). The most problematic regulations to follow were "at least 10 hours of rest between duty hours" (36.9%), "24-hour limit of continuous care plus 6 additional hours for continuity of care and educational objectives" (26.1%), and "80-hour work limit over 4 weeks" (22.7%). Education and continuity in patient care were the main reasons associated with noncompliance. Noncompliance was highest in trauma (25.2%) and vascular surgery (16.3%) residents. In addition, 65.2% of the attending physicians do not agree with implementing work-hour regulation standards in the surgical faculty. CONCLUSIONS: The survey demonstrates that noncompliance with the work-hour regulation is prevalent. The reasons for noncompliance are multifactorial. These findings will help restructure training programs in the efforts to increase compliance with the work-hour regulation.

Management and treatment of iliopsoas abscess.

HYPOTHESIS: Even with improved diagnostic modalities, the optimum management strategy for iliopsoas abscess (IPA) is not uniform, and a better understanding of treatment options is needed. DESIGN: Retrospective case series. SETTING: Academic center. PATIENTS: Sixty-one consecutive patients diagnosed as having IPA at the Mount Sinai Medical Center, New York, New York, from August 1, 2000, to December 30, 2007. MAIN OUTCOME MEASURES: Development and cause of IPA, the need for additional interventions, morbidity, and mortality. RESULTS: The mean age of the patients was 53 years. Most patients were initially seen with pain (95% [58 of 61]), gastrointestinal tract complaints (43% [26 of 61]), and lower extremity pain (30% [18 of 61]). Primary and secondary abscesses occurred in 11% (7 of 61) and 89% (54 of 61), respectively. The most frequent underlying cause of secondary abscesses was inflammatory bowel disease. Broad-spectrum antibiotics were prescribed in all patients. Computed tomography was the most common diagnostic modality used. Abscesses were larger than 6 cm in 39% of patients (24 of 61), bilateral in 13% (8 of 61), and multiple in 25% (15 of 61). Nine patients were treated using antibiotics alone, with a success rate of 78% (7 of 9). Forty-eight patients initially underwent percutaneous drainage, which was successful in 40% (19 of 48). Among those with unresolved IPAs, 71% of patients ultimately required surgery, and the IPAs were typically associated with underlying gastrointestinal tract causes. Seven percent (4 of 61) of patients directly underwent exploratory surgery and drainage, and all of these interventions were successful. The overall mortality was 5% (3 of 61). CONCLUSIONS: Iliopsoas abscess remains a therapeutic challenge. Gastrointestinal tract disease is the most common cause, with computed tomography as the diagnostic modality of choice. Percutaneous drainage remains the initial treatment modality but is rarely the sole therapy required. Patients with inflammatory bowel disease are likely to require ultimate operative management.