Shona D'Arcy

A Method to Assess Adherence in Inhaler Use through Analysis of Acoustic Recordings of Inhaler Events

Rationale Poor adherence to inhaler use can be due to poor temporal and/or technique adherence. Up until now there has been no way of reliably tracking both these factors in everyday inhaler use. Objectives This paper introduces a device developed to create time stamped acoustic recordings of an individuals inhaler use, in which empirical evidence of temporal and technique adherence in inhaler use can be monitored over time. The correlation between clinical outcomes and adherence, as determined by this device, was compared for temporal adherence alone and combined temporal and technique adherence. Findings The technology was validated by showing that the doses taken matched the number of audio recordings (r2 = 0.94, p<0.01). To demonstrate that audio analysis of inhaler use gives objective information, in vitro studies were performed. These showed that acoustic profiles of inhalations correlated with the peak inspiratory flow rate (r2 = 0.97, p<0.01), and that the acoustic energy of exhalations into the inhaler was related to the amount of drug removed. Despite training, 16% of participants exhaled into the mouthpiece after priming, in >20% of their inhaler events. Repeated training reduced this to 7% of participants (p = 0.03). When time of use was considered, there was no evidence of a relationship between adherence and changes in AQLQ (r2 = 0.2) or PEFR (r2 = 0.2). Combining time and technique the rate of adherence was related to changes in AQLQ (r2 = 0.53, p = 0.01) and PEFR (r2 = 0.29, p = 0.01). Conclusions This study presents a novel method to objectively assess how errors in both time and technique of inhaler use impact on clinical outcomes. Trial Registration EudraCT 2011-004149-42

A randomised clinical trial of feedback on inhaler adherence and technique in patients with severe uncontrolled asthma

In severe asthma, poor control could reflect issues of medication adherence or inhaler technique, or that the condition is refractory. This study aimed to determine if an intervention with (bio)feedback on the features of inhaler use would identify refractory asthma and enhance inhaler technique and adherence. Patients with severe uncontrolled asthma were subjected to a stratified-by-site random block design. The intensive education group received repeated training in inhaler use, adherence and disease management. The intervention group received the same intervention, enhanced by (bio)feedback-guided training. The primary outcome was rate of actual inhaler adherence. Secondary outcomes included a pre-defined assessment of clinical outcome. Outcome assessors were blinded to group allocation. Data were analysed on an intention-to-treat and per-protocol basis. The mean rate of adherence during the third month in the (bio)feedback group (n=111) was higher than that in the enhanced education group (intention-to-treat, n=107; 73% versus 63%; 95% CI 2.8%–17.6%; p=0.02). By the end of the study, asthma was either stable or improved in 54 patients (38%); uncontrolled, but poorly adherent in 52 (35%); and uncontrolled, but adherent in 40 (27%). Repeated feedback significantly improved inhaler adherence. After a programme of adherence and inhaler technique assessment, only 40 patients (27%) were refractory and adherent, and might therefore need add-on therapy. On a period of monitored adherence only 27% of patients were refractory and adherent and thus need add-on therapy http://ow.ly/ddQr30gTpmb

A protocol for a randomised clinical trial of the effect of providing feedback on inhaler technique and adherence from an electronic device in patients with poorly controlled severe asthma

Introduction In clinical practice, it is difficult to distinguish between patients with refractory asthma from those with poorly controlled asthma, where symptoms persist due to poor adherence, inadequate inhaler technique or comorbid diseases. We designed an audio recording device which, when attached to an inhaler, objectively identifies the time and technique of inhaler use, thereby assessing both aspects of adherence. This study will test the hypothesis that feedback on these two aspects of adherence when passed on to patients improves adherence and helps clinicians distinguish refractory from difficult-to-control asthma. Methods This is a single, blind, prospective, randomised, clinical trial performed at 5 research centres. Patients with partially controlled or uncontrolled severe asthma who have also had at least one severe asthma exacerbation in the prior year are eligible to participate. The effect of two types of nurse-delivered education interventions to promote adherence and inhaler technique will be assessed. The active group will receive feedback on their inhaler technique and adherence from the new device over a 3-month period. The control group will also receive training in inhaler technique and strategies to promote adherence, but no feedback from the device. The primary outcome is the difference in actual adherence, a measure that incorporates time and technique of inhaler use between groups at the end of the third month. Secondary outcomes include the number of patients who remain refractory despite good adherence, and differences in the components of adherence after the intervention. Data will be analysed on an intention-to-treat and a per-protocol basis. The sample size is 220 subjects (110 in each group), and loss to follow-up is estimated at 10% which will allow results to show a 10% difference (0.8 power) in adherence between group means with a type I error probability of 0.05. Trial registration number NCT01529697; Pre-results.

An acoustic method to automatically detect pressurized metered dose inhaler actuations.

Chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) affect over 400 million people and are incurable. The pressurized metered dose inhaler (pMDI) has been the most popular inhaler device in inhaled therapy in recent times. However the pMDIs require good coordination between inhaling and actuating the inhaler to deliver the aerosolized drug most effectively. Poor coordination can greatly reduce the amount of drug delivered to a patient and therefore reducing the control of respiratory disease symptoms. Acoustic methods have been recently employed to monitor inhaler technique quite effectively. This study employs a noninvasive acoustic method to detect actuation sounds in a portable monitoring device. A total of 158 actuation sounds were obtained from a group of healthy subjects (n=5) and subjects suffering from respiratory diseases (n=15). The developed algorithm generated an overall accuracy of 99.7% demonstrating that this method may have clinical potential to monitor pMDI actuation coordination. The informative feedback from this method may also be employed in clinical training to highlight patient actuation technique.

An acoustic method of automatically evaluating patient inhaler technique

Chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) affect millions of people worldwide. Inhalers are devices utilized to deliver medication in small doses directly to the airways in the treatment of asthma and COPD. Despite the proven effectiveness of inhaler medication in controlling symptoms, many patients suffer from technique errors leading to decreased levels of medication efficacy. This study employs a recording device attached to a commonly used dry powder inhaler (DPI) to obtain the acoustic signals of patients taking their inhaler medication. The audio files provide information on how a patient uses their inhaler over a period of one month. Manually listening to such a large quantity of audio files would be a time consuming and monotonous process and therefore an algorithm that could automatically carry out this task would be of great benefit. An algorithm was thus designed and developed to detect inhalation, exhalation and blister events in the audio signals, analyze the quantity of each event, the order in which the events took place and finally provide a score on the overall performance. The algorithm was tested on a dataset of 185 audio files obtained from five community dwelling asthmatic patients in real world environments. Evaluation of the algorithm on this dataset revealed that it had an accuracy of 92.8% in deciding the correct technique score compared to manual detection methods.

Using acoustics to estimate inspiratory flow rate and drug removed from a dry powder inhaler

Morbidity and mortality rates of chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) are rising. There is a strong requirement for more effective management of these chronic diseases. Dry powder inhalers (DPIs) are one kind of devices currently employed to deliver medication aimed at controlling asthma and COPD symptoms. Despite their proven effectiveness when used correctly, some patients are unable to reach the inspiratory flow rate required to remove medication from the breath actuated devices and as a result, the medication does not reach the airways. This study employs an acoustic recording device, attached to a common DPI to record the audio signals of simulated inhalations. A rotameter was used to measure the flow rate through the inhaler while a milligram weighing scale was used to measure the amount of drug removed from each simulated inhalation. It was found that a strong correlation existed (R2>0.96) when average power, median amplitude, root mean square and mean absolute deviation were used to predict peak inspiratory flow rate. At a flow of 30L/Min (mean absolute deviation=0.0049), it was found that 77% of the total emitted dose was removed from the inhaler. Results indicate that acoustic measurements may be used in the prediction of inspiratory flow rate and quantity of medication removed from an inhaler.

An Investigation of Feasibility and Safety of Bi-Modal Stimulation for the Treatment of Tinnitus: An Open-Label Pilot Study.

Tinnitus is the perception of sound in the absence of an external auditory stimulus. It is widely believed that tinnitus, in patients with associated hearing loss, is a neurological phenomenon primarily affecting the central auditory structures. However, there is growing evidence for the involvement of the somatosensory system in this form of tinnitus. For this reason it has been suggested that the condition may be amenable to bi‐modal stimulation of the auditory and somatosensory systems. We conducted a pilot study to investigate the feasibility and safety of a device that delivers simultaneous auditory and somatosensory stimulation to treat the symptoms of chronic tinnitus.

A study into the automation of cognitive assessment tasks for delivery via the telephone: Lessons for developing remote monitoring applications for the elderly

BACKGROUND Cognitive assessments are valuable tools in assessing neurological conditions. They are critical in measuring deficits in cognitive function in an array of neurological disorders and during the ageing process. Automation of cognitive assessments is one way to address the increasing burden on medical resources for an ever increasing ageing population. OBJECTIVE This study investigated the suitability of using automated Interactive Voice Response (IVR) technology to deliver a suite of cognitive assessments to older adults using speech as the input modality. METHODS Several clinically valid and gold-standard cognitive assessments were selected for implementation in the IVR application. The IVR application was designed using human centred design principles to ensure the experience was as user friendly as possible. Sixty one participants completed two IVR assessments and one face to face (FF) assessment with a neuropsychologist. Completion rates for individual tests were inspected to identify those tests that are most suitable for administration via IVR technology. Interclass correlations were calculated to assess the reliability of the automated administration of the cognitive assessments across delivery modes. RESULTS While all participants successfully completed all automated assessments, variability in the completion rates for different cognitive tests was observed. Statistical analysis found significant interclass correlations for certain cognitive tests between the different modes of administration. Analysis also suggests that an initial FF assessment reduces the variability in cognitive test scores when introducing automation into such an assessment. CONCLUSION [corrected] This study has demonstrated the functional and cognitive reliability of administering specific cognitive tests using an automated, speech driven application. This study has defined the characteristics of existing cognitive tests that are suitable for such an automated delivery system and also informs on the limitations of other cognitive tests for this modality. This study presents recommendations for developing future large scale cognitive assessments.

Dynamic minimum pause threshold estimation for speech analysis in studies of cognitive function in ageing

Cognitive decline represents the biggest limiting factor to independence in older adults. Speech analysis has emerged as an alternative to standard cognitive assessment tools. Temporal segmentation of speech is reported in many studies and typically employs a static threshold to define a pause. This study investigated the effect of using pause and utterance duration distribution data in differentiating between cognitively healthy and impaired older adults. Three sets of features were extracted from 187 speech recordings: temporal features using a static 250ms threshold; temporal features using a dynamic threshold; and pause and utterance duration distribution parameters. The ability of each of these sets to differentiate between cognitively healthy and cognitively impaired participants was investigated using a Linear Discriminant Analysis (LDA) classifier. Improvements of 0.22% (to 64.20%) in sensitivity, 6.33% (73.12%) in specificity, and 3.27% (68.66%) in overall accuracy were observed in the performance of the classifier using the pause and utterance duration distribution parameters when compared to the static temporal features. The use of the dynamic threshold had a negative impact on the classifier performance, with a decrease of 5.73% (to 58.25%) in sensitivity, 1.10% (65.69%) in specificity, and 3.42% (61.97%) in accuracy.