Maxine Power

Driving Plasticity in Human Adult Motor Cortex Is Associated with Improved Motor Function after Brain Injury

Changes in somatosensory input can remodel human cortical motor organization, yet the input characteristics that promote reorganization and their functional significance have not been explored. Here we show with transcranial magnetic stimulation that sensory-driven reorganization of human motor cortex is highly dependent upon the frequency, intensity, and duration of stimulus applied. Those patterns of input associated with enhanced excitability (5 Hz, 75% maximal tolerated intensity for 10 min) induce stronger cortical activation to fMRI. When applied to acutely dysphagic stroke patients, swallowing corticobulbar excitability is increased mainly in the undamaged hemisphere, being strongly correlated with an improvement in swallowing function. Thus, input to the human adult brain can be programmed to promote beneficial changes in neuroplasticity and function after cerebral injury.

Recovery of swallowing after dysphagic stroke relates to functional reorganization in the intact motor cortex

BACKGROUND & AIMS The aim of this study was to determine the mechanism for recovery of swallowing after dysphagic stroke. METHODS Twenty-eight patients who had a unilateral hemispheric stroke were studied 1 week and 1 and 3 months after the stroke by videofluoroscopy. Pharyngeal and thenar electromyographic responses to magnetic stimulation of multiple sites over both hemispheres were recorded, and motor representations were correlated with swallowing recovery. RESULTS Dysphagia was initially present in 71% of patients and in 46% and 41% of the patients at 1 and 3 months, respectively. Cortical representation of the pharynx was smaller in the affected hemisphere (5 +/- 1 sites) than the unaffected hemisphere (13 +/- 1 sites; P </= 0.001). Nondysphagic and persistently dysphagic patients showed little change in pharyngeal representation in either hemisphere at 1 and 3 months compared with presentation, but dysphagic patients who recovered had an increased pharyngeal representation in the unaffected hemisphere at 1 and 3 months (15 +/- 2 and 17 +/- 3 vs. 9 +/- 2 sites; P </= 0.02) without change in the affected hemisphere. In contrast, thenar representation increased in the affected hemisphere but not the unaffected hemisphere at 1 and 3 months (P </= 0.01). CONCLUSIONS Return of swallowing after dysphagic stroke is associated with increased pharyngeal representation in the unaffected hemisphere, suggesting a role for intact hemisphere reorganization in recovery.

Modulation of human swallowing behaviour by thermal and chemical stimulation in health and after brain injury.

Abstract Few data support thermal or chemical stimulation as therapy for neurogenic dysphagia. Our aims were to explore the behavioural effects of thermal (cold) and chemical (citrus) modalities on water swallowing in health (n = 65, mean age 45 years, 44 females) and acute stroke (n = 22, mean age 67 years, eight females). Multiple randomized timed 50‐mL swallowing tests were performed for each of four water conditions: (a) room temperature (RT), (b) cold (CD), (c) citrus (CT) and (d) combined cold and citrus (CD + CT). The inter‐swallow interval (ISI), swallowing volume velocity (speed), and volume per swallow (capacity) were measured. In health, compared to RT, only CD + CT slowed the speed (12.3 ± 0.5 vs 10.3 ± 0.5 mL s−1, P < 0.03) and decreased the capacity (16.4 ± 0.9 vs 14.6 ± 0.7 mL per swallow, P < 0.02) of swallowing. ISI was unaffected, except by CD + CT in healthy young subjects (<60 years) where it was reduced (1.44 ± 0.02 vs 1.30 ± 0.02 s, P < 0.02). Despite smaller volumes ingested by stroke patients, CD + CT, compared to RT, again slowed both the speed (3.8 ± 0.4 vs 4.5 ± 0.5 mL s−1, P < 0.03) and capacity (7.6 ± 0.7 vs 8.5 ± 0.7 mL per swallow, P < 0.03) of swallowing but had no effect on ISI. We conclude that combined thermal and chemical modification of water consistently alters swallowing behaviour in health and after cerebral injury. These findings have relevance in the management of neurogenic swallowing problems.

Awareness of Dysphagia by Patients Following Stroke Predicts Swallowing Performance

Patients’ awareness of their disability after stroke represents an important aspect of functional recovery. Our study aimed to assess whether patient awareness of the clinical indicators of dysphagia, used routinely in clinical assessment, related to an appreciation of “a swallowing problem” and how this awareness influenced swallowing performance and outcome in dysphagic stroke patients. Seventy patients were studied 72 h post hemispheric stroke. Patients were screened for dysphagia by clinical assessment, followed by a timed water swallow test to examine swallowing performance. Patient awareness of dysphagia and its significance were determined by detailed question-based assessment. Medical records were examined at three months. Dysphagia was identified in 27 patients, 16 of whom had poor awareness of their dysphagic symptoms. Dysphagic patients with poor awareness drank water more quickly (5 ml/s vs. <1 ml/s, p = 0.03) and took larger volumes per swallow (10 ml vs. 6 ml, p = 0.04) than patients with good awareness. By comparison, neither patients with good awareness or poor awareness perceived they had a swallowing problem. Patients with poor awareness experienced numerically more complications at three months. Stroke patients with good awareness of the clinical indicators of dysphagia modify the way they drink by taking smaller volumes per swallow and drink more slowly than those with poor awareness. Dysphagic stroke patients, regardless of good or poor awareness of the clinical indicators of dysphagia, rarely perceive they have a swallowing problem. These findings may have implications for longer-term outcome, patient compliance, and treatment of dysphagia after stroke.

Deglutitive laryngeal closure in stroke patients

Background: Dysphagia has been reported in up to 70% of patients with stroke, predisposing them to aspiration and pneumonia. Despite this, the mechanism for aspiration remains unclear. Aims: To determine the relationship between bolus flow and laryngeal closure during swallowing in patients with stroke and to examine the sensorimotor mechanisms leading to aspiration. Methods: Measures of swallowing and bolus flow were taken from digital videofluoroscopic images in 90 patients with stroke and 50 healthy adults, after repeated volitional swallows of controlled volumes of thin liquid. Aspiration was assessed using a validated Penetration–Aspiration Scale. Oral sensation was also measured by electrical stimulation at the faucial pillars. Results: After stroke, laryngeal ascent was delayed (mean (standard deviation (SD)) 0.31 (0.06) s, p<0.001), resulting in prolongation of pharyngeal transit time (1.17 (0.07) s, p<0.001) without a concomitant increase in laryngeal closure duration (0.84 (0.04) s, p = 0.9). The delay in laryngeal elevation correlated with both the severity of aspiration (r = 0.5, p<0.001) and oral sensation (r = 0.5, p<0.001). Conclusions: After stroke, duration of laryngeal delay and degree of sensory deficit are associated with the severity of aspiration. These findings indicate a role for sensorimotor interactions in control of swallowing and have implications for the assessment and management of dysphagia after stroke.

Evaluating Oral Stimulation as a Treatment for Dysphagia after Stroke

Deglutitive aspiration is common after stroke and can have devastating consequences. While the application of oral sensory stimulation as a treatment for dysphagia remains controversial, data from our laboratory have suggested that it may increase corticobulbar excitability, which in previous work was correlated with swallowing recovery after stroke. Our study assessed the effects of oral stimulation at the faucial pillar on measures of swallowing and aspiration in patients with dysphagic stroke. Swallowing was assessed before and 60 min after 0.2-Hz electrical or sham stimulation in 16 stroke patients (12 male, mean age = 73 ± 12 years). Swallowing measures included laryngeal closure (initiation and duration) and pharyngeal transit time, taken from digitally acquired videofluoroscopy. Aspiration severity was assessed using a validated penetration-aspiration scale. Preintervention, the initiation of laryngeal closure, was delayed in both groups, occurring 0.66 ± 0.17 s after the bolus arrived at the hypopharynx. The larynx was closed for 0.79 ± 0.07 s and pharyngeal transit time was 0.94 ± 0.06 s. Baseline swallowing measures and aspiration severity were similar between groups (stimulation: 24.9 ± 3.01; sham: 24.9 ± 3.3, p = 0.2). Compared with baseline, no change was observed in the speed of laryngeal elevation, pharyngeal transit time, or aspiration severity within subjects or between groups for either active or sham stimulation. Our study found no evidence for functional change in swallow physiology after faucial pillar stimulation in dysphagic stroke. Therefore, with the parameters used in this study, oral stimulation does not offer an effective treatment for poststroke patients.

Did a quality improvement collaborative make stroke care better? A cluster randomized trial

BackgroundStroke can result in death and long-term disability. Fast and high-quality care can reduce the impact of stroke, but UK national audit data has demonstrated variability in compliance with recommended processes of care. Though quality improvement collaboratives (QICs) are widely used, whether a QIC could improve reliability of stroke care was unknown.MethodsTwenty-four NHS hospitals in the Northwest of England were randomly allocated to participate either in Stroke 90:10, a QIC based on the Breakthrough Series (BTS) model, or to a control group giving normal care. The QIC focused on nine processes of quality care for stroke already used in the national stroke audit. The nine processes were grouped into two distinct care bundles: one relating to early hours care and one relating to rehabilitation following stroke. Using an interrupted time series design and difference-in-difference analysis, we aimed to determine whether hospitals participating in the QIC improved more than the control group on bundle compliance.ResultsData were available from nine interventions (3,533 patients) and nine control hospitals (3,059 patients). Hospitals in the QIC showed a modest improvement from baseline in the odds of average compliance equivalent to a relative improvement of 10.9% (95% CI 1.3%, 20.6%) in the Early Hours Bundle and 11.2% (95% CI 1.4%, 21.5%) in the Rehabilitation Bundle. Secondary analysis suggested that some specific processes were more sensitive to an intervention effect.ConclusionsSome aspects of stroke care improved during the QIC, but the effects of the QIC were modest and further improvement is needed. The extent to which a BTS QIC can improve quality of stroke care remains uncertain. Some aspects of care may respond better to collaboratives than others.Trial registrationISRCTN13893902.

What is the NHS Safety Thermometer

The English National Health Service (NHS) announced a new programme to incentivize use of the NHS Safety Thermometer (NHS ST) in the NHS Operating Framework for 2012/13. For the first time, the NHS is using the Commissioning for Quality and Innovation (CQUIN) scheme, a contract lever, to incentivize ALL providers of NHS care to measure four common complications (harms) using the NHS ST in a proactive way on one day per month. This national CQUIN scheme provides financial reward for the collection of baseline data with a view to incentivizing the achievement of improvement goals in later years. In this paper, we describe the rationale for this large-scale data collection, the purpose of the instrument and its potential contribution to our current understanding of patient safety. It is not a comprehensive description of the method or preliminary data. This will be published separately. The focus of the NHS ST on pressure ulcers, falls, catheters and urine infection and venous thromboembolism is broadly applicable to patients across all healthcare settings, but is specifically pertinent to older people who, experiencing more healthcare intervention, are at risk of not one but multiple harms. In this paper, we also describe an innovative patient-level composite measure of the absence of harm from the four identified, termed as “harmfreecare” which is unique to the NHS ST and is under development to raise standards for patient safety.

Learning from the design and development of the NHS Safety Thermometer

Quality issue Research indicates that 10% of patients are harmed by healthcare but data that can be used in real time to improve safety are not routinely available. Initial assessment We identified the need for a prospective safety measurement system that healthcare professionals can use to improve safety locally, regionally and nationally. Choice of solution We designed, developed and implemented a national tool, named the NHS Safety Thermometer (NHS ST) with the goal of measuring the prevalence of harm from pressure ulcers, falls, urinary tract infection in patients with catheters and venous thromboembolism on one day each month for all NHS patients. Implementation The NHS ST survey instrument was developed in a learning collaborative involving 161 organizations (e.g. hospitals and other delivery organizations) using a Plan, Do, Study, Act method. Evaluation Testing of operational definitions, technical capability and use were conducted and feedback systems were established by site coordinators in each participating organization. During the 17-month pilot, site coordinators reported a total of 73 651 patient entries. Lessons learned It is feasible to obtain national data through standardized reporting by site coordinators at the point of care. Some caution is required in interpreting data and work is required locally to ensure data collection systems are robust and data collectors were trained. Sampling is an important strategy to optimize efficiency and reduce the burden of measurement.

How collaborative are quality improvement collaboratives: a qualitative study in stroke care

BackgroundQuality improvement collaboratives (QICs) continue to be widely used, yet evidence for their effectiveness is equivocal. We sought to explain what happened in Stroke 90:10, a QIC designed to improve stroke care in 24 hospitals in the North West of England. Our study drew in part on the literature on collective action and inter-organizational collaboration. This literature has been relatively neglected in evaluations of QICs, even though they are founded on principles of co-operation and sharing.MethodsWe interviewed 32 professionals in hospitals that participated in Stroke 90:10, conducted a focus group with the QIC faculty team, and reviewed purposively sampled documents including reports and newsletters. Analysis was based on a modified form of Framework Analysis, combining sensitizing constructs derived from the literature and new, empirically derived thematic categories.ResultsImprovements in stroke care were attributed to QIC participation by many professionals. They described how the QIC fostered a sense of community and increased attention to stroke care within their organizations. However, participants’ experiences of the QIC varied. Starting positions were different; some organizations were achieving higher levels of performance than others before the QIC began, and some had more pre-existing experience of quality improvement methods. Some participants had more to learn, others more to teach. Some evidence of free-riding was found. Benchmarking improvement was variously experienced as friendly rivalry or as time-consuming and stressful. Participants’ competitive desire to demonstrate success sometimes conflicted with collaborative aims; some experienced competing organizational pressures or saw the QIC as duplication of effort. Experiences of inter-organizational collaboration were influenced by variations in intra-organizational support.ConclusionsCollaboration is not the only mode of behavior likely to occur within a QIC. Our study revealed a mixed picture of collaboration, free-riding and competition. QICs should learn from work on the challenges of collective action; set realistic goals; account for context; ensure sufficient time and resources are made available; and carefully manage the collaborative to mitigate the risks of collaborative inertia and unhelpful competitive or anti-cooperative behaviors. Individual organizations should assess the costs and benefits of collaboration as a means of attaining quality improvement.