The subjective–objective mismatch in sleep perception among those with insomnia and sleep apnea

The diagnosis and management of insomnia relies primarily on clinical history. However, patient self‐report of sleep–wake times may not agree with objective measurements. We hypothesized that those with shallow or fragmented sleep would under‐report sleep quantity, and that this might account for some of the mismatch. We compared objective and subjective sleep–wake times for 277 patients who underwent diagnostic polysomnography. The group included those with insomnia symptoms (n = 92), obstructive sleep apnea (n = 66) or both (n = 119). Mismatch of wake duration was context dependent: all three groups overestimated sleep latency but underestimated wakefulness after sleep onset. The insomnia group underestimated total sleep time by a median of 81 min. However, contrary to our hypothesis, measures of fragmentation (N1, arousal index, sleep efficiency, etc.) did not correlate with the subjective sleep duration estimates. To unmask a potential relationship between sleep architecture and subjective duration, we tested three hypotheses: N1 is perceived as wake; sleep bouts under 10 min are perceived as wake; or N1 and N2 are perceived in a weighted fashion. None of these hypotheses exposed a match between subjective and objective sleep duration. We show only modest performance of a Naïve Bayes Classifier algorithm for predicting mismatch using clinical and polysomnographic variables. Subjective–objective mismatch is common in patients reporting insomnia symptoms. We conclude that mismatch was not attributable to commonly measured polysomnographic measures of fragmentation. Further insight is needed into the complex relationships between subjective perception of sleep and conventional, objective measurements.     

Ablation of porcine ligamentum flavum with Ho:YAG,q‐switched Ho:YAG,and quadrupled Nd:YAG lasers

Background and Objectives

Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser‐coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q‐switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF.

Study Design/Materials and Methods

LF was resected from porcine spine within 2 hours of sacrifice and stored in saline until immediately prior to laser irradiation, which occurred within an additional 2 hours. The optical absorbance of a sample was measured over the spectral band from 190 to 2,360 nm both before and after dehydration. For the experiments using the Ho:YAG (λ = 2,080 nm, t_p = 140 µs, FWHM) and Q‐Switched Ho:YAG (λ = 2,080 nm, t_p = 260 ns, FWHM) lasers, energy was delivered to the LF through a laser‐fiber optic with 600 µm core and NA = 0.39. For the experiment using the frequency quadrupled Nd:YAG laser (λ = 266 nm, t_p = 5 ns FWHM), rather than applying the laser energy through a laser‐fiber, the energy was focused through an aperture and lens directly onto the LF. Five experiments were conducted to evaluate the effect of the given lasers on LF. First, using the Ho:YAG laser, the single‐pulse laser‐hole depth versus laser fluence was measured with the laser‐fiber in direct contact with the LF (1 g force) and with a standoff distance of 1 mm between the laser‐fiber face and the LF. Second, with the LF remaining in situ and the spine bisected along the coronal plane, the surface temperature of the LF was measured with an IR camera during irradiation with the Ho:YAG laser, with and without constant saline flush. Third, the mass loss was measured over the course of 450 Ho:YAG pulses. Fourth, hole depth and temperature were measured over 30 pulses of fixed fluence from the Ho:YAG and Q‐Switched Ho:YAG lasers. Fifth, the ablation rate and surface temperature were measured as a function of fluence from the Nd:YAG laser. Several LF staining and hole‐depth measurement techniques were also explored.

Results

Aside from the expected absorbance peaks corresponding to the water in the LF, the most significant peaks in absorbance were located in the spectral band from 190 to 290 nm and persisted after the tissue was dehydrated. In the first experiment, using the Ho:YAG laser and with the laser‐fiber in direct contact with the LF, the lowest single‐pulse fluence for which LF was visibly removed was 35 J/cm². Testing was conducted at 6 fluences between 35 and 354 J/cm². Over this range the single‐pulse hole depth was shown to be near linear (R² = 0.9374, M = 1.6), ranging from 40 to 639 µm (N = 3). For the case where the laser‐fiber face was displaced 1 mm from the LF surface, the lowest single‐pulse fluence for which tissue was visibly removed was 72 J/cm². Testing was conducted at 4 energy densities between 72 and 180 J/cm². Over this range the single‐pulse hole depth was shown to be near linear (R² = 0.8951, M = 1.4), ranging from 31 to 220 µm (N = 3). In the second experiment, with LF in situ, constant flushing with room temperature saline was shown to drastically reduce surface temperature during exposure to Ho:YAG at 5 Hz with the laser‐fiber in direct contact with the LF. Without saline, over 1 minute of treatment with a per‐pulse fluence of 141 mJ/cm², the average maximum surface temperature measured 110°C. With 10 cc's of saline flushed over 1 minute and a per‐pulse laser fluence of 212 mJ/cm², the average maximum surface temperature was 35°C. In the third experiment, mass loss was shown to be linear over 450 pulses of 600 mJ from the Ho:YAG laser (212 J/cm², direct contact, N = 4; 108 J/cm², 1 mm standoff, N = 4). With the laser‐fiber in direct contact, an average of 53 mg was removed (R² = 0.996, M = 0.117) and with 1 mm laser‐fiber standoff, an average of 44 mg was removed (R² = 0.9988, M = 0.097). In the fourth experiment, 30 pulses of the Ho:YAG and Q‐Switched Ho:YAG lasers at 1 mm standoff, and 5 Hz produced similar hole depths for the tested fluences of 9 J/cm² (151 and 154 µm, respectively) and 18 J/cm² (470 and 442 µm, respectively), though the Ho:YAG laser produced significantly more carbonization around the rim of the laser‐hole. The increased carbonization was corroborated by higher measured LF temperature. In all tests with the Ho:YAG and Q‐Switched Ho:YAG, an audible photo‐acoustic affect coincided with the laser pulse. In the fifth experiment, with the frequency quadrupled Nd:YAG laser at 15 Hz for 450 pulses, ablation depth per pulse was shown to be linear for the fluence range of 0.18 – 0.73 J/cm² (R² = 0.989, M = 2.4). There was no noticeable photo‐acoustic effect nor charring around the rim of the laser‐hole.

Conclusion

The Ho:YAG, Q‐Switched Ho:YAG, and frequency quadrupled Nd:YAG lasers were shown to remove ligamentum flavum (LF). A single pulse of the Ho:YAG laser was shown to cause tearing of the tissue and a large zone of necrosis surrounding the laser‐hole. Multiple pulses of the Ho:YAG and Q‐Switched Ho:YAG lasers caused charring around the rim of the laser‐hole, though the extent of charring was more extensive with the Ho:YAG laser. Charring caused by the Ho:YAG laser was shown to be mitigated by continuously flushing the affected LF with saline during irradiation. The Nd:YAG laser was shown to ablate LF with no gross visible indication of thermal damage to surrounding LF. Lasers Surg. Med. 47:839–851, 2015. © 2015 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.     

TEMPORAL PATTERN OF KINESIOLOGY TAPE EFFICACY ON HAMSTRING EXTENSIBILITY

Background

Kinesiology tape has been advocated as a means of improving muscle flexibility, a potential modifiable risk factor for injury, over time. The epidemiology and etiology of hamstring injuries in sport have been well documented.

Purpose

To compare the temporal pattern of efficacy of kinesiology tape and traditional stretching techniques on hamstring extensibility over a five day period.

Study Design

Controlled laboratory study.

Methods

Thirty recreationally active male participants (Mean ± SD: age 20.0 ± 1.55 years; height 179.3 ± 4.94 cm; mass 76.9 ± 7.57 kg) completed an active knee extension assessment (of the dominant leg) as a measure of hamstring extensibility. Three experimental interventions were applied in randomized order: Kinesiology tape (KT), static stretch (SS), proprioceptive neuromuscular facilitation (PNF). Measures were taken at baseline, +1min, + 30mins, + 3days and +5days days after each intervention. The temporal pattern of change in active knee extension was modelled as a range of regression polynomials for each intervention, quantified as the regression coefficient.

Results

Hamstring ROM with KT application at +3days was significantly greater than baseline (129.18 ± 15.46%, p = 0.01), SS (106.99 ± 9.84%, p = 0.03) and PNF (107.42 ± 136.13%, p = 0.03) interventions. The temporal pattern of changes in ROM for SS and PNF were best modelled by a negative linear function, although the strength of the correlation was weak in each case. In contrast, the KT data was optimised using a quadratic polynomial function (r² = 0.60), which yielded an optimum time of 2.76 days, eliciting a predicted ROM of 129.6% relative to baseline.

Conclusion

Each intervention displayed a unique temporal pattern of changes in active knee extension. SS was best suited to immediate improvements, and PNF to +30 minutes in hamstring extensibility, whereas kinesiology tape offered advantages over a longer duration, peaking at 2.76 days. These findings have implications for the choice of intervention, timing and duration to assist clinicians in both a sporting and clinical context.

Level of evidence

2c     

Molecular and Biochemical Characterization of CTX-M-131, a Natural Asp240Gly Variant Derived from CTX-M-2, Produced by a Providencia rettgeri Clinical Strain in S?o Paulo,Brazil

CTX-M-131 is a natural Asp240Gly variant from the CTX-M-2 group detected in a Providencia rettgeri clinical strain from Brazil. Molecular analysis showed that bla_CTX-M-131 was inserted in a complex class 1 integron harbored by a 112-kb plasmid, which has not been previously described as a platform for CTX-M-encoding genes with the Asp240Gly mutation. Steady-state kinetic parameters showed that the enzyme has a typical cefotaximase catalytic profile and an enhanced activity against ceftazidime.     

Health Economic Modelling of Treatment Sequences for Rheumatoid Arthritis: A Systematic Review

The objective of the work reported in this paper was to critically assess how sequential disease-modifying anti-rheumatic drugs (DMARDs) have been modelled in the context of economic evaluation of the use of DMARDs for treatment of rheumatoid arthritis (RA). A secondary purpose was to identify the methodological challenges of modelling sequential therapies. Systematic searches of 10 databases were undertaken in February 2013. Studies were included if they were in the English language and a full comparative economic evaluation was reported. They were appraised by use of the Drummond checklist (Appendix to this paper). Data extracted included economic evaluation data, data relating to sequential treatment, and data on the modelling methods used. Fifty-seven studies were identified, with 25 (44 %) modelling a sequence of treatments. Forty-three (75 %) were cost–utility analyses. Eleven (19 %) were UK studies and 11 (19 %) were US. The remainder were mainly European (26 (46 %)). A distinction was made between studies of recent-onset RA (14 (25 %)) and those of established RA (42 (74 %)). One study (1 %) was unclear. Individual-level models were more likely to meet the Drummond criteria and evaluate sequences. No study identified an optimum sequence of multiple treatments given a set of treatment options. The level of reporting of the methods and evidence used to assess the effect of downstream treatments in the sequence was generally poor. When lifelong models and downstream treatment sequences were considered, evidence gaps were identified. The review discovered that methods have not been consistently applied, leading to varied estimates of cost-effectiveness. Treatment sequences have not been fully considered and modelled, potentially resulting in inaccurate estimates of cost-effectiveness.