1,963 research outputs found
Is there a link between dizziness and vision? A systematic review
YesPurpose: The aim of this study was to systematically review the literature to investigate
the link (if any) between vision and dizziness.
Methods: Medline, CINAHL, AMED, Web of Science and The Cochrane Library
were searched with keywords chosen to find articles which investigated the causes
of dizziness and considered vision as a possible trigger. Citation chaining of all
included papers was performed in addition to the hand searching of all reference
lists. Unpublished literature was identified using www.opengrey.eu. The review
considered studies involving adults which link, measure or attempt to improve
any aspect of vision in relation to dizziness.
Results: Nine thousand six hundred and eighty one possible references were
found, and the abstracts were screened independently by two reviewers to determine
if they should be included in the study. Thirteen papers were found which
investigated whether dizziness was linked to an assessment of vision. Visual
impairment measures were crude and typically self-report, or Snellen visual acuity
with little or no measurement details. Five studies found an independent link
between dizziness and vision, five found a weak association (typically finding a
link when univariate analyses were used, but not when multivariate analyses were
used), and three found no association. Studies finding a strong link were usually
cross-sectional with a large study population whereas those finding a weak association
had relatively small numbers of participants. Studies which did not find an
association used a broad definition of dizziness that included the term light-headedness,
an unreliable Rosenbaum near visual acuity chart or an unusual categorisation
of visual acuity.
Conclusions: This review suggests that dizziness (although likely not ‘light-headedness’)
is linked with poor vision although further studies using more appropriate
measures of vision are recommended.Deborah Armstrong was funded by a College of Optometrists Research Scholarship and Emily Charlesworth by a College of Optometrists summer studentship
Interference between postural control and mental task performance in patients with vestibular disorder and healthy controls
OBJECTIVES - To determine whether interference between postural control and mental task performance in patients with balance system impairment and healthy subjects is due to general capacity limitations, motor control interference, competition for spatial processing resources, or a combination of these.METHOD - Postural stability was assessed in 48 patients with vestibular disorder and 24 healthy controls while they were standing with eyes closed on (a) a stable and (b) a moving platform. Mental task performance was measured by accuracy and reaction time on mental tasks, comprising high and low load, spatial and non-spatial tasks. Interference between balancing and performing mental tasks was assessed by comparing baseline (single task) levels of sway and mental task performance with levels while concurrently balancing and carrying out mental tasks.RESULTS - As the balancing task increased in difficulty, reaction times on both low load mental tasks grew progressively longer and accuracy on both high load tasks declined in patients and controls. Postural sway was essentially unaffected by mental activity in patients and controls.CONCLUSIONS - It is unlikely that dual task interference between balancing and mental activity is due to competition for spatial processing resources, as levels of interference were similar in patients with vestibular disorder and healthy controls, and were also similar for spatial and non-spatial tasks. Moreover, the finding that accuracy declined on the high load tasks when balancing cannot be attributed to motor control interference, as no motor control processing is involved in maintaining accuracy of responses. Therefore, interference between mental activity and postural control can be attributed principally to general capacity limitations, and is hence proportional to the attentional demands of both tasks
Psychometric properties of the Vertigo symptom scale – Short form
<p>Abstract</p> <p>Background</p> <p>The aim of the study was to examine the psychometric properties of the Vertigo symptom scale – short form (VSS-SF), a condition-specific measure of dizziness, following translation of the scale into Norwegian.</p> <p>Methods</p> <p>A cross-sectional survey design was used to examine the factor structure, internal consistency and discriminative ability (sample I, n = 503). A cross-sectional pre-intervention design was used to examine the construct validity (sample II, n = 36) of the measure and a test-retest design was used to examine reliability (sub-sample of sample II, n = 28).</p> <p>Results</p> <p>The scree plot indicated a two factor structure accounting respectively for 41% and 12% of the variance prior to rotation. The factors were related to vertigo-balance (VSS-V) and autonomic-anxiety (VSS-A). Twelve of the items loaded clearly on either of the two dimensions, while three items cross-loaded. Internal consistency of the VSS-SF was high (alpha = 0.90). Construct validity was indicated by correlation between path length registered by platform posturography and the VSS-V (r = 0.52), but not with the VSS-A. The ability to discriminate between dizzy and not dizzy patients was excellent for the VSS-SF and sub-dimension VSS-V (area under the curve 0.87 and 0.91, respectively), and acceptable for the sub-dimension VSS-A (area under the curve 0.77). High test-retest reliability was demonstrated (ICC VSS-SF: 0.88, VSS-V: 0.90, VSS-A: 0.90) and no systematic change was observed in the scores from test to retest after 2 days.</p> <p>Conclusion</p> <p>Using a Norwegian translated version of the VSS-SF, this is the first study to provide evidence of the construct validity of this instrument demonstrating a stable two factor structure of the scale, and the identified sub-dimensions of dizziness were related to vertigo-balance and autonomic-anxiety, respectively. Evidence regarding a physical construct underlying the vertigo-balance sub-scale was provided. Satisfactory internal consistency was indicated, and the discriminative ability of the instruments was demonstrated. The instrument showed satisfactory test-retest reliability.</p
Developing digital interventions: a methodological guide.
Digital interventions are becoming an increasingly popular method of delivering healthcare as they enable and promote patient self-management. This paper provides a methodological guide to the processes involved in developing effective digital interventions, detailing how to plan and develop such interventions to avoid common pitfalls. It demonstrates the need for mixed qualitative and quantitative methods in order to develop digital interventions which are effective, feasible, and acceptable to users and stakeholders
Flexible autonomy: an online approach to developing mathematics subject knowledge for teachers
This paper uses an adaptation of Brookfield’s (2017) lenses to critically reflect upon a Subject Knowledge Enhancement Course designed and taught by the authors.
Learning occurs through a synthesis of asynchronous engagement with online e-learning modules, weekly synchronous tutorials and self-reflection following formative and summative assessment opportunities. Interrogating the course design, learner feedback and observation, and tutor pedagogic choices through connectivist and social constructivist learning theory, the paper concludes that the common perceived learning gains occur through the flexibility in learning, and the supported autonomy that learners are given. Further developments in our offer should therefore aim to improve these opportunities for learners where possible
Flux cancellation and the evolution of the eruptive filament of 2011 June 7
We investigate whether flux cancellation is responsible for the formation of
a very massive filament resulting in the spectacular 2011 June 7 eruption. We
analyse and quantify the amount of flux cancellation that occurs in NOAA AR
11226 and its two neighbouring ARs (11227 & 11233) using line-of-sight
magnetograms from the Heliospheric Magnetic Imager. During a 3.6-day period
building up to the filament eruption, 1.7 x 10^21 Mx, 21% of AR 11226's maximum
magnetic flux, was cancelled along the polarity inversion line (PIL) where the
filament formed. If the flux cancellation continued at the same rate up until
the eruption then up to 2.8 x 10^21 Mx (34% of the AR flux) may have been built
into the magnetic configuration that contains the filament plasma. The large
flux cancellation rate is due to an unusual motion of the positive polarity
sunspot, which splits, with the largest section moving rapidly towards the PIL.
This motion compresses the negative polarity and leads to the formation of an
orphan penumbra where one end of the filament is rooted. Dense plasma threads
above the orphan penumbra build into the filament, extending its length, and
presumably injecting material into it. We conclude that the exceptionally
strong flux cancellation in AR 11226 played a significant role in the formation
of its unusually massive filament. In addition, the presence and coherent
evolution of bald patches in the vector magnetic field along the PIL suggests
that the magnetic field configuration supporting the filament material is that
of a flux rope.Comment: 18 pages, 7 figures. Submitted to ApJ in December 2015, accepted in
June 201
FIP Bias Evolution in a Decaying Active Region
Solar coronal plasma composition is typically characterized by first
ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging
Spectrometer (EIS) instrument, we present a series of large-scale, spatially
resolved composition maps of active region (AR) 11389. The composition maps
show how FIP bias evolves within the decaying AR from 2012 January 4-6.
Globally, FIP bias decreases throughout the AR. We analyzed areas of
significant plasma composition changes within the decaying AR and found that
small-scale evolution in the photospheric magnetic field is closely linked to
the FIP bias evolution observed in the corona. During the AR's decay phase,
small bipoles emerging within supergranular cells reconnect with the
pre-existing AR field, creating a pathway along which photospheric and coronal
plasmas can mix. The mixing time scales are shorter than those of plasma
enrichment processes. Eruptive activity also results in shifting the FIP bias
closer to photospheric in the affected areas. Finally, the FIP bias still
remains dominantly coronal only in a part of the AR's high-flux density core.
We conclude that in the decay phase of an AR's lifetime, the FIP bias is
becoming increasingly modulated by episodes of small-scale flux emergence, i.e.
decreasing the AR's overall FIP bias. Our results show that magnetic field
evolution plays an important role in compositional changes during AR
development, revealing a more complex relationship than expected from previous
well-known Skylab results showing that FIP bias increases almost linearly with
age in young ARs (Widing Feldman, 2001, ApJ, 555, 426)
Use of reactance with synchronous converters: An insurance to continuity of service and a protection to apparatus
n/
Social Networking: An astronomer's field guide
We present a brief introduction to the phenomenon of "social networking" and
its potentially powerful use as an astronomy outreach and educational tool. We
briefly discuss the development of applications for websites and facebook and
the use of web trackers e.g. Google Analytics to analyze your audience. Finally
we discuss how social bookmarking can be used to promote your work to
unexpected audiences.Comment: 10 pages, conferenc
Adherence to prophylaxis in adolescents and young adults with severe haemophilia, A qualitative study with patients
© 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Abstract Introduction: Reported levels of adherence to prophylaxis among young people with haemophilia (YPH) vary widely and are predominately based on estimations made by healthcare professionals and parents. Reasons for (non)adherence among YPH in particular have not been evidenced. Aim: to examine experiences in relation to prophylaxis with YPH themselves, and barriers and facilitators to their adherence. Methods: 11 Participants were recruited in five haemophilia centres across England and Wales. All patients who met the inclusion criteria (aged 12-25, diagnosed with haemophilia, on prophylaxis) were approached during a routine check-up appointment, and all participants who agreed to take part were interviewed. Interviews were audio recorded, transcribed and analysed using Interpretative Phenomenological Analysis. Results: Self-reported adherence to prophylaxis was good. Few participants admitted to intentionally skipping injections although they reported sometimes forgetting. However, due to the increasingly personalised and flexible approach to prophylaxis, adherence is not straightforward to define. Barriers to adherence included a busy lifestyle, dislike of the intravenous injection, venous access issues, anxiety or stress and being out of one’s normal routine. Support was an important facilitator to adherence, including support from health professionals at the haemophilia centre as well as friends. Parents appear to be very involved with their sons’ haemophilia management, even after their sons leave home. Conclusion: What this study adds is that the increasingly flexible and personalized approach to managing prophylaxis in haemophilia may sometimes lead to confusion around treatment frequency and dosing. This may lead to accidental non-adherence, which is distinct from both skipping and forgetting. Advice from haemophilia teams may not always be consistent, and is likely to be interpreted differently by different individuals. Some additional training and education of patients and their families to increase their knowledge and skills around prophylaxis may reduce this confusion and therefore is likely to improve adherence further.Peer reviewedFinal Published versio
- …