Towards single-photon Brillouin optical time domain reflectometry.

We investigate a novel distributed Brillouin optical time domain reflectometer (BOTDR) using standard telecommunication fibers based on single-photon avalanche diodes (SPADs) in gated mode, ν -BOTDR, with a range of 120 km and 10 m spatial resolution. We experimentally demonstrate the ability to perform a distributed temperature measurement, by detecting a hot spot at 100 km. Instead of using a frequency scan like conventional BOTDR, we use a frequency discriminator based on the slope of a fiber Bragg grating (FBG) to convert the count rate of the SPAD into a frequency shift. A procedure to take into account the FBG drift during the acquisition and perform sensitive and reliable distributed measurements is described. We also present the possibility to differentiate strain and temperature.

Cancellation of reference update-induced 1/f noise in a chirped-pulse DAS.

Distributed acoustic sensors (DAS) perform distributed and dynamic strain or temperature change measurements by comparing a measured time-domain trace with a previous fiber reference state. Large strain or temperature fluctuations or laser frequency noise impose the need to update such a reference, making it necessary to integrate the short-term variation measurements if absolute strain or temperature variations are to be obtained. This has the drawback of introducing a 1/f noise component, as noise is integrated with each cumulative variation measurement, which is detrimental to the determination of very slow processes (i.e., in the mHz frequency range or below). This work analyzes the long-term stability of chirped-pulse phase-sensitive optical time-domain reflectometry (CP-ΦOTDR) with multi-frequency database demodulation (MFDD) to carry out "calibrated" measurements in a DAS along an unmodified SMF. It is shown that, under the conditions studied in this work, a "calibrated" chirped-pulse DAS (CP-DAS) with a completely suppressed reference update-induced 1/f noise component is achieved capable of making measurements over periods of more than 2 months with the same set of references, even when switching off the interrogator during the measurement.

Long-distance distributed pressure sensing based on frequency-scanned phase-sensitive optical time-domain reflectometry.

In this paper, a long-distance distributed pressure sensing system based on a special fiber and using frequency-scanned phase-sensitive optical time-domain reflectometry is proposed. The fiber shows high pressure sensitivity (159 MHz/bar) and low loss (3 dB/km) owing to its simple structure made of two large air holes in the cladding. The pressure response of the two orthogonal polarization axes of the fiber is explored distinctively. Distributed pressure sensing over a long sensing range (720 m) and high spatial resolution (5 cm) is demonstrated, resulting in 14,400 resolved sensing points with uncertainty on pressure of 0.49 bar. Discrimination between the temperature/strain and pressure responses is demonstrated, taking advantage of the different pressure and temperature sensitivities of the two polarization axes. In addition, the temperature response of the fiber is studied and the simulation results show the possibility of scaling the temperature sensitivity by adjusting the size of the core. The sensing distance limit due to crosstalk between the polarization axes is also discussed.

A Biopsychosocial Evaluation of Post-Acute Outcome of Patients with Severe Brain Lesions Recovering from Coma: An Exploratory Study.

Currently, very little is known about the holistic outcome of patients recovering from coma. The aim of this retrospective exploratory study was to evaluate the outcomes of patients recovering from coma after care in an acute neurorehabilitation unit with particular focus on their biopsychosocial and spiritual needs in the post-acute phase of recovery. We included 12 patients and evaluated clinical outcome evolution by comparing standard neurobehavioral scores from patient files measured in the acute and post-acute phases. We assessed patient needs using the Quality of Life after Brain Injury scale (QOLIBRI) and classified self-reported complaints mentioned in patient files according to the International Classification of Functioning, Disability and Health framework (ICF). Mean patient evolution was a Level of Cognitive Functioning Scale (LCF)-r increase of 3.33 levels (range = 2); a Disability Rating Scale score (DRS) of -3.27 points (SD = 3.78); a Functional Ambulation Classification (FAC) scale score of 1.83 (range = 5); and a Glasgow Outcome Scale (GOS) median = 0 (Interquartile range = 1). Main patient complaints concerned mental functioning (n = 7), sensory functioning and pain (n = 6), neuromusculoskeletal and movement problems (n = 5), and major life areas (n = 5). To conclude, a significant handicap that affects their daily life was present in the post-acute phase in most patients. Complaints involved biopsychosocial and spiritual elements. The neurobehavioral scale results do not necessarily correlate with the subjective representations patients had of their condition.

Validation of the Spiritual Distress Assessment Tool in older hospitalized patients.

BACKGROUND: The Spiritual Distress Assessment Tool (SDAT) is a 5-item instrument developed to assess unmet spiritual needs in hospitalized elderly patients and to determine the presence of spiritual distress. The objective of this study was to investigate the SDAT psychometric properties. METHODS: This cross-sectional study was performed in a Geriatric Rehabilitation Unit. Patients (N = 203), aged 65 years and over with Mini Mental State Exam score ≥ 20, were consecutively enrolled over a 6-month period. Data on health, functional, cognitive, affective and spiritual status were collected upon admission. Interviews using the SDAT (score from 0 to 15, higher scores indicating higher distress) were conducted by a trained chaplain. Factor analysis, measures of internal consistency (inter-item and item-to-total correlations, Cronbach α), and reliability (intra-rater and inter-rater) were performed. Criterion-related validity was assessed using the Functional Assessment of Chronic Illness Therapy-Spiritual well-being (FACIT-Sp) and the question "Are you at peace?" as criterion-standard. Concurrent and predictive validity were assessed using the Geriatric Depression Scale (GDS), occurrence of a family meeting, hospital length of stay (LOS) and destination at discharge. RESULTS: SDAT scores ranged from 1 to 11 (mean 5.6 ± 2.4). Overall, 65.0% (132/203) of the patients reported some spiritual distress on SDAT total score and 22.2% (45/203) reported at least one severe unmet spiritual need. A two-factor solution explained 60% of the variance. Inter-item correlations ranged from 0.11 to 0.41 (eight out of ten with P < 0.05). Item-to-total correlations ranged from 0.57 to 0.66 (all P < 0.001). Cronbach α was acceptable (0.60). Intra-rater and inter-rater reliabilities were high (Intraclass Correlation Coefficients ranging from 0.87 to 0.96). SDAT correlated significantly with the FACIT-Sp, "Are you at peace?", GDS (Rho -0.45, -0.33, and 0.43, respectively, all P < .001), and LOS (Rho 0.15, P = .03). Compared with patients showing no severely unmet spiritual need, patients with at least one severe unmet spiritual need had higher odds of occurrence of a family meeting (adjOR 4.7, 95%CI 1.4-16.3, P = .02) and were more often discharged to a nursing home (13.3% vs 3.8%; P = .027). CONCLUSIONS: SDAT has acceptable psychometrics properties and appears to be a valid and reliable instrument to assess spiritual distress in elderly hospitalized patients.

Wish to Die Among Residents of Swiss Long-Term Care Facilities: A Multisite Cross-Sectional Study.

OBJECTIVES: The wish to die (WTD) in persons near the end of life is a clinically important, ethically and practically complex phenomenon as demonstrated by the intense debates on assisted dying legislation around the world. Despite global aging and increasing institutionalization in old age, WTD among residents of long-term care facilities (LTCF) is underexplored. We aimed to assess the prevalence of WTD and identify its predictors in older LTCF residents. DESIGN: Multisite cross-sectional observational study. SETTING AND PARTICIPANTS: 31 LTCF in the 3 major linguistic regions of Switzerland, including residents 75 years or older, admitted to the LTCF 4 to 10 months before the study, without severe cognitive impairment. METHODS: Between February 2013 and June 2017, trained research staff interviewed residents to assess WTD using 2 validated instruments and collected information on potential predictors, including depressive symptoms, anxiety, demoralization, feeling to be a burden, spiritual distress, symptom burden, multimorbidity, and drug use. Demographic data were obtained by chart review. Descriptive statistics as well as univariate and multivariate regression analyses were performed. RESULTS: From 427 eligible residents, 101 were excluded, 46 refused, and 280 were included in the study (acceptance rate 85.9%). In general, residents readily and openly addressed the topic of WTD. The prevalence of WTD was 16.0% and 16.2% according to the 2 instruments, with all but 1 of the residents expressing a passive WTD. The strongest independent predictors for a WTD were depressive symptoms (OR 7.45 and 5.77 for the 2 WTD assessment instruments) and demoralization (OR 2.62 and 3.66). CONCLUSIONS AND IMPLICATIONS: The WTD is a relevant concern affecting approximately 1 in 6 LTCF residents. Further research is needed to investigate which interventions could best address the potentially modifiable factors that were associated with the WTD in this specific setting and population.

Instruments measuring spirituality in clinical research: a systematic review.

INTRODUCTION: Numerous instruments have been developed to assess spirituality and measure its association with health outcomes. This study's aims were to identify instruments used in clinical research that measure spirituality; to propose a classification of these instruments; and to identify those instruments that could provide information on the need for spiritual intervention. METHODS: A systematic literature search in MEDLINE, CINHAL, PsycINFO, ATLA, and EMBASE databases, using the terms "spirituality" and "adult$," and limited to journal articles was performed to identify clinical studies that used a spiritual assessment instrument. For each instrument identified, measured constructs, intended goals, and data on psychometric properties were retrieved. A conceptual and a functional classification of instruments were developed. RESULTS: Thirty-five instruments were retrieved and classified into measures of general spirituality (N = 22), spiritual well-being (N = 5), spiritual coping (N = 4), and spiritual needs (N = 4) according to the conceptual classification. Instruments most frequently used in clinical research were the FACIT-Sp and the Spiritual Well-Being Scale. Data on psychometric properties were mostly limited to content validity and inter-item reliability. According to the functional classification, 16 instruments were identified that included at least one item measuring a current spiritual state, but only three of those appeared suitable to address the need for spiritual intervention. CONCLUSIONS: Instruments identified in this systematic review assess multiple dimensions of spirituality, and the proposed classifications should help clinical researchers interested in investigating the complex relationship between spirituality and health. Findings underscore the scarcity of instruments specifically designed to measure a patient's current spiritual state. Moreover, the relatively limited data available on psychometric properties of these instruments highlight the need for additional research to determine whether they are suitable in identifying the need for spiritual interventions.

The spiritual distress assessment tool: an instrument to assess spiritual distress in hospitalised elderly persons.

BACKGROUND: Although spirituality is usually considered a positive resource for coping with illness, spiritual distress may have a negative influence on health outcomes. Tools are needed to identify spiritual distress in clinical practice and subsequently address identified needs. This study describes the first steps in the development of a clinically acceptable instrument to assess spiritual distress in hospitalized elderly patients. METHODS: A three-step process was used to develop the Spiritual Distress Assessment Tool (SDAT): 1) Conceptualisation by a multidisciplinary group of a model (Spiritual Needs Model) to define the different dimensions characterizing a patient's spirituality and their corresponding needs; 2) Operationalisation of the Spiritual Needs Model within geriatric hospital care leading to a set of questions (SDAT) investigating needs related to each of the defined dimensions; 3) Qualitative assessment of the instrument's acceptability and face validity in hospital chaplains. RESULTS: Four dimensions of spirituality (Meaning, Transcendence, Values, and Psychosocial Identity) and their corresponding needs were defined. A formalised assessment procedure to both identify and subsequently score unmet spiritual needs and spiritual distress was developed. Face validity and acceptability in clinical practice were confirmed by chaplains involved in the focus groups. CONCLUSIONS: The SDAT appears to be a clinically acceptable instrument to assess spiritual distress in elderly hospitalised persons. Studies are ongoing to investigate the psychometric properties of the instrument and to assess its potential to serve as a basis for integrating the spiritual dimension in the patient's plan of care.

What Motivates Healthcare Professionals' Referrals to Chaplains, and How to Help Them Formulate Referrals that Accurately Reflect Patients' Spiritual Needs?

As many hospitals lack standardized referral protocols for spiritual care, healthcare professionals' perceptions and preferences play an important role in their decisions to refer patients to chaplains. To better understand what motivates these professionals to refer patients and how they approach spiritual care, this article examines referral requests from twelve healthcare professionals to a chaplain at the Lausanne University Hospital Department of Physical and Rehabilitation Medicine. Comparative discourse analysis highlights that requests are largely driven by difficulties in patient-professional relationships. Yet, further interviews reveal that healthcare professionals construct spiritual care as a way to access patients' sense of identity and explore the meaning they give to their lives and experiences, for the benefit of both patients and professionals. The discussion considers how chaplains could help healthcare colleagues formulate referrals that accurately reflect patients' spiritual needs, thus improving the relevance and quality of spiritual care.

Wish to Die in Older Patients: Development and Validation of Two Assessment Instruments.

OBJECTIVES: The wish to die may be different in geriatric patients than in younger terminally ill patients. This study aimed to develop and validate instruments for assessing the wish to die in geriatric patients. DESIGN: Cross-sectional study. SETTING: Geriatric rehabilitation unit of a university hospital. PARTICIPANTS: Patients (N = 101) aged 65 years or older with a Mini-Mental State Examination score of 20 or higher, admitted consecutively over a 5-month period. MEASUREMENTS: The Schedule of Attitudes Toward Hastened Death (SAHD) was adapted to the older population (SAHD-Senior). A second tool was developed based on qualitative literature, the Categories of Attitudes Toward Death Occurrence (CADO). After cognitive pretesting, these instruments were validated in a sample of patients admitted to a geriatric rehabilitation unit. RESULTS: The SAHD-Senior showed good psychometric properties and a unifactorial structure. In the studied sample, 12.9% had a SAHD-Senior score of 10 or higher, suggesting a significant wish to die. Associations were observed between high levels of the SAHD-Senior and advanced age, high levels of depressive symptoms, lower quality of life, and lower cognitive function. The CADO allowed for passive death wishes to be distinguished from wishes to actively hasten death. According to the CADO, 14.9% of the sample had a wish to die. The two instruments showed a concordance rate of 90.1%. CONCLUSION: The wish to die in older patients admitted to rehabilitation can be validly assessed with two novel instruments. The considerable proportion with a wish to die warrants investigation into concept, determinants, and management of the wish to die. J Am Geriatr Soc 68:1202-1209, 2020.

Experiences of newly diagnosed cancer patients in confronting the finitudes of life: a qualitative systematic review protocol.

REVIEW QUESTION: What is the experience of newly diagnosed patients with cancer when facing the finitude of life and undergoing initial anti-cancer treatment?

Factors associated with quality of life in elderly hospitalised patients undergoing post-acute rehabilitation: a cross-sectional analytical study in Switzerland.

OBJECTIVES: We investigated whether biopsychosocial and spiritual factors and satisfaction with care were associated with patients' perceived quality of life. DESIGN: This was a cross-sectional analytical study. SETTING: Data were collected from inpatients at a postacute geriatric rehabilitation centre in a university hospital in Switzerland. PARTICIPANTS: Participants aged 65 years and over were consecutively recruited from October 2014 to January 2016. Exclusion criteria included significant cognitive disorder and terminal illness. Of 227 eligible participants, complete data were collected from 167. MAIN OUTCOME MEASURES: Perceived quality of life was measured using WHO Quality of Life Questionnaire-version for older people. Predictive factors were age, sex, functional status at admission, comorbidities, cognitive status, depressive symptoms, living conditions and satisfaction with care. A secondary focus was the association between spiritual needs and quality of life. RESULTS: Patients undergoing geriatric rehabilitation experienced a good quality of life. Greater quality of life was significantly associated with higher functional status (rs=0.204, p=0.011), better cognitive status (rs=0.175, p=0.029) and greater satisfaction with care (rs=0.264, p=0.003). Poorer quality of life was significantly associated with comorbidities (rs=-.226, p=0.033), greater depressive symptoms (rs=-.379, p<0.001) and unmet spiritual needs (rs=-.211, p=0.049). Multivariate linear regression indicated that depressive symptoms (ß=-0.961; 95% CIs -1.449 to 0.472; p<0.001) significantly predicted quality of life. CONCLUSIONS: Patient perceptions of quality of life were significantly associated with depression. More research is needed to assess whether considering quality of life could improve care plan creation.

Polarisation and wavelength division multiplexing at 1.55 mum for bandwidth enhancement of multimode fibre based access networks.

We demonstrate how a combination of polarisation-division multiplexing (PDM) and wavelength-division multiplexing (WDM) applied to graded index 50 mum multimode fibres (MMF) at 1.55 mum can be used to greatly increase the available optical bandwidth. A proof of principle experiment demonstrated error-free data transmission over 3km of MMF, using two 100GHz-spaced wavelengths, each carrying two 2.5Gb/s orthogonal PDM multiplexed channels, resulting in a 10Gb/s data rate. Polarisation and wavelength demultiplexing were simultaneously achieved by use of a grating based monochromator. We also practically implemented this transmission scheme in an all-fibre experiment, replacing the monochromator by a more convenient polarisation-insensitive, 200GHz ITU grid spacing 62.5 mum MMF pigtailed WDM demultiplexer. Using two polarizations each on four wavelengths (2P x 4lambda), we repeatedly achieved error-free data transmission for both circularly and linearly polarisation-wavelength-division-multiplexed channels over a MMF span of 300m, featuring a 20Gb/s data rate. Overall, we have demonstrated a major increase in the MMF bandwidth-distance product up to 30GHz-km.

C-band polarisation orthogonality preservation in 5Gb/s, 50microm multimode fibre links up to 3km.

We have investigated the polarisation-maintenance capability of 50microm graded-index multimode fibres (MMF) in the Cband. Using both circularly, and linearly polarisation-multiplexed signals centre-launched into the MMF, we found that orthogonality is sufficiently maintained in both cases to yield typically 10dB optical isolation between the channels.Using orthogonally circular polarisationmultiplexed signals, we show experimentally that two 3 and 5Gb/s data channels may be transmitted error free over 50microm multimode fibre spans up to 3km in length.

Experimental demonstration of cascaded AWG access network featuring bi-directional transmission and polarization multiplexing.

We present the first experimental demonstration of a bidirectional cascaded arrayed-waveguide grating (AWG) access network combining one NxN AWG in the central office with multiple 1xN AWG's at the distribution points, such as to individually address N(2) users with only N wavelengths. Downstream and upstream data share the same optical path. BER curves were measured using 2.5Gb/s data stream in each direction, and error free transmission achieved for downstream and upstream, with only 0.3dB power penalty for simultaneous transmission. The addition of two orthogonal polarization-multiplexed channels per wavelength doubled the number of possible end users. Error free transmission was achieved with simultaneous upstream and downstream transmission of a composite signal featuring eight 2.5Gb/s channels (2 polarizations x 4 wavelengths).

Polarimetric fiber laser sensor for hydrostatic pressure.

A polarimetric Fabry-Perot fiber laser sensor for fluid pressure up to 100 MPa is investigated. The fluid acts on one of two elliptical-core fiber sections in the laser cavity, producing a shift in the differential phase of the two orthogonal polarization modes and thus a variation in the beat frequencies of the corresponding longitudinal laser modes. The second fiber section, with a 90 degrees offset in the core orientation, compensates for temperature-induced phase shifts. The dispersion in the birefringent fiber Bragg grating reflectors is employed to remove the near degeneracy of the polarization mode beat frequencies of a given order and to improve substantially the resolution of the sensor to a few parts in 10(6) of the free spectral range. Further investigations address the effect of the fluid on the integrity of the fiber, the influence of various fiber coatings on the sensor response, and the intrinsic stability of erbium-doped and undoped sensing fibers under fluid pressure.