Alice Hon

Changing trends in the management of end-stage neuromuscular respiratory muscle failure: recommendations of an international consensus.

ObjectiveRespiratory management of patients with end-stage respiratory muscle failure of neuromuscular disease has evolved from no treatment and inevitable respiratory failure to the use of up to continuous noninvasive intermittent positive pressure ventilatory support (CNVS) to avert respiratory failure and to permit the extubation of “unweanable” patients without tracheostomy. An international panel experienced in CNVS was charged by the 69th Congress of the Mexican Society of Pulmonologists and Thoracic Surgeons to analyze changing respiratory management trends and to make recommendations. DesignNeuromuscular disease respiratory consensuses and reviews were identified from PubMed. Individual respiratory interventions were identified; their importance was established by assessing the quality of evidence-based literature for each one and their patterns of use over time. The panel then determined the evidence-based strength for the efficacy of each intervention and made recommendations for achieving prolonged survival by CNVS. ResultsFifty publications since 1993 were identified. Continuous positive airway pressure, oxygen therapy, bilevel positive airway pressure used at both low and high spans, “air stacking,” manually assisted coughing, low pressure (<35 cm H2O) and high pressure (≥40 cm H2O) mechanically assisted coughing, noninvasive positive pressure ventilation part time (<23 hrs per day) and full time (>23 hrs per day; CNVS), extubation and decannulation of ventilator-dependent patients to CNVS, and oximetry feedback for noninvasive positive pressure ventilation and mechanically assisted coughing were identified. All noted interventions are being used with increasing frequency and were unanimously recommended to achieve prolonged survival by CNVS, with the exception of supplemental oxygen and continuous positive airway pressure, which are being used less and were not recommended for this population. ConclusionsCNVS and extubation of unweanable patients to CNVS are increasingly being used to prolong life while avoiding invasive interfaces.

Contrast polarity preservation’s role in perception: Explained and unexplained stimuli

Roncato and Casco (2003, Perception & Psychophysics 65 1252–1272) had shown that in situations where the Gestalt principle of good continuity is put into conflict with preservation of contrast polarity (CP) the perception that preserves CP prevails. Parlangeli and Roncato (2010, Perception 39 255–259) have studied this question of preservation of CP more closely and have added an addendum to the rule. They have used stimuli consisting of a checkerboard of perpendicularly arranged rectangular bricks (white, gray, or black) and draughtsmen–white, gray, or black disks placed at the corners of the bricks. This study has caused them to add an addendum to the rule of CP-preserved path-conjunction binding: if there are two contour completions that preserve the CP, the one with the higher contrast will prevail. Parlangeli and Roncato find that, for certain shades of the disks and bricks, the perpendicular lines of the checkerboard appear strikingly to be slanted or undulating. Here we consider all possible arrangements of relative magnitudes of checkerboards consisting of bricks of two different shades and disks of two shades as well, as such arrangements with widely varying differences in the magnitude of brightness. We have found a number of cases where the perception is not explained by the rule and addendum of Roncato and Casco, and Parlangeli and Roncato, and a case where preservation of “distant” as well as local CP plays a role in perception. The previously known cases, and the new exceptional unexplained stimuli we have found, warrant further study.

Thickness and the Koffka Ring Effect

Over seven decades ago Gestalt psychologist Kurt Koffka described a remarkable effect: when a contiguous gray ring is placed on a background half of one shade of gray, half of another, the ring appears homogeneous. However, if the ring is slightly divided, the two halves of the ring appear different shades of gray, the half of the ring on the darker background appearing lighter than the half of the ring on the lighter background. The Gestalt principle of continuity is used to explain this effect. We show that when the ring is made thinner it appears heterogeneous even when contiguous. We also illustrate this in the additional material with a colored background with more than two regions.

Evaluating the Use of Medicare Part D in the Veteran Population With Spinal Cord Injury/Disorder

OBJECTIVE To examine the different sources of medications, the most common drug classes filled, and the characteristics associated with Medicare Part D pharmacy use in veterans with spinal cord injury/disorder (SCI/D). DESIGN Retrospective, cross-sectional, observational study. SETTING Outpatient clinics and pharmacies. PARTICIPANTS Veterans (N=13,442) with SCI/D using Medicare or Veteran Affairs pharmacy benefits. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Characteristics and top 10 most common drug classes were examined in veterans who (1) used VA pharmacies only; (2) used both VA and Medicare Part D pharmacies; or (3) used Part D pharmacies only. Chi-square tests and multinomial logistic regression analyses were used to determine associations between various patient variables and source of medications. Patient level frequencies were used to determine the most common drug classes. RESULTS A total of 13,442 veterans with SCI/D were analyzed in this study: 11,788 (87.7%) used VA pharmacies only, 1281 (9.5%) used both VA and Part D pharmacies, and 373 (2.8%) used Part D pharmacies only. Veterans older than 50 years were more likely to use Part D pharmacies, whereas those with traumatic injury, or secondary conditions, were less associated with the use of Part D pharmacies. Opioids were the most frequently filled drug class across all groups. Other frequently used drug classes included skeletal muscle relaxants, gastric medications, antidepressants (other category), anticonvulsants, and antilipemics. CONCLUSIONS Approximately 12% of veterans with SCI/D are receiving medication outside the VA system. Polypharmacy in this population of veterans is relatively high, emphasizing the importance of health information exchange between systems for improved care for this medically complex population.

Not physically present contours can yield illusory motion.

We demonstrate a perceptual effect whereby contours not physically present in a visual scene can yield striking illusory motion. The not physically present contours are paths of invariant contrast polarity (CP). For example, when a square checkerboard composed of dark and light square checks with small black and white discs covering the vertices is put in lateral motion, there is the striking perception of vertical expansion/contraction. Such a checkerboard has (not physically present) diagonal paths of CP presentation with vertical components. However, when a square checkerboard made up of square black and very light checks with gray discs of luminance intermediate to the checks is put in lateral motion, no expansion/contraction is seen. For this checkerboard the vertical components of paths of CP preservation cancel each other out, predicting the lack of perception of vertical expansion/contraction. We also discuss how not physically present contours can explain previously described effects and suggest new effects to be explored.

Respiratory Muscle Aids in the Management of Neuromuscular Respiratory Impairment to Prevent Respiratory Failure and Need for Tracheostomy

Respiratory impairment results from primary disease of the lungs / airways or from impairment of the respiratory muscles. The proper identification of the respiratory impairment allows for proper management to decrease morbidity and mortality. Patients with neuromuscular impairment typically have hypoventilation or ventilator insufficiency/failure resulting in hypercapnia, hypoxia and an ineffective cough. In contrast, lung and airway diseases are characterized by hypoxia with eucapnia or hypocapnia, which often occur during an exacerbation resulting in acute respiratory failure (ARF). Often physicians evaluate and treat both as respiratory insufficiency/failure.

Koffka's Effect is Mediated by Figure Thickness at the Joining Region

Three-quarters of a century ago Gestalt psychologist Kurt Koffka described a remarkable effect: when a contiguous gray ring is placed on a background half one shade of gray, half another, the ring appears homogeneous. However, if the ring is divided, the two halves of the ring appear different shades of gray, the half of the ring on the darker background appearing lighter than the half of the ring on the lighter background. The Gestalt principle of continuity is used to explain this effect. But what microscopic principles might be mediating this effect? Recently we found sufficiently thin rings (annuli) appear heterogeneous even when geometrically continuous. Here, using crescent-shaped figures instead of the circular annuli used for the traditional Koffka effect, we show that this effect of thickness of the ring is mediated by the thickness at the boundary of the region where the halves of the figure are joined.

The Wertheimer–Benary Effect Does Not Invert, and a Nulled Wertheimer–Benary Effect

More than three-quarters of a century ago Wertheimer and Benary demonstrated an ingenious and clear, though, interestingly, small effect: a grey triangle just inside an arm of a black cross on a white background appears slightly lighter than an identical triangle immediately adjacent to the cross, despite both triangles having the same perimeter exposure to black and white. Over a generation ago White discovered an apparently related, but far stronger effect: when short grey (test) bars are placed onto either black or white alternating long bars, the short test bars placed on the long black bars appear much lighter than those placed on the long white bars. A decade ago Spehar, Gilchrist, and Arend found that, enigmatically, if the short test bars in Whites effect are the lightest stimulus in a figure, then the relative lightness of the test bars inverts compared with the standard version of Whites effect. Here we show that the Wertheimer–Benary effect does not invert, but instead produces a very weak version of the standard effect. We also demonstrate a novel, nulled Wertheimer-Benary effect.