W. G. Selley

Comparative Review of Techniques for Recording Respiratory Events at Rest and during Deglutition

Abstract. The coordination between swallowing and respiration is essential for safe feeding, and noninvasive feeding-respiratory instrumentation has been used in feeding and dysphagia assessment. Sometimes there are differences of interpretation of the data produced by the various respiratory monitoring techniques, some of which may be inappropriate for observing the rapid respiratory events associated with deglutition. Following a review of each of the main techniques employed for recording resting, pre-feeding, feeding, and post-feeding respiration on different subject groups (infants, children, and adults), a critical comparison of the methods is illustrated by simultaneous recordings from various respiratory transducers. As a result, a minimal combination of instruments is recommended which can provide the necessary respiratory information for routine feeding assessments in a clinical environment.

The synchronization of respiration and swallow sounds with videofluoroscopy during swallowing

Simultaneous recording of adult subjects sipping small amounts of fluid from a cup have been obtained by videofluoroscopy together with feeding respiratory patterns and swallow sounds from the Exeter Dysphagia Assessment Technique (EDAT). These allowed visual representations of respiration and swallow sounds to be superimposed on a videofluoroscopy recording using a split-screen technique. Sequentially numbered, 1/50 sec, half-frame photographic prints were examined and schematic drawings of the relevant radiographs were made. These were superimposed on to the actual EDAT printed chart of the same swallow event, theri exact time relationship with respiration and cervical swallow sounds being preserved. The results allow events in the barium videofluoroscopy to be related to events in the feeding respiratory pattern and swallow sounds recorded by EDAT.

Dysphagia following strokes: Clinical observations of swallowing rehabilitation employing Palatal Training Appliances

A retrospective study was undertaken to evaluate the progress of a group of dysphagic stroke patients for whom a dental prosthesis the Palatal Training Appliance (PTA), was used in the active rehabilitation of the swallowing mechanism. Patients selected were those who had sustained a stroke uncomplicated by other neurological illness, during one 12-month period, and whose dysphagia caused anxiety to the medical staff in the hospital ward. Thirty severely dysphagic stroke patients satisfied these criteria. The study recorded the duration and type of supplementary feeding required during hospitalization. Thirteen patients had evidence of aspiration before the PTA was fitted and 5 afterwards. Seven patients died, but only 1 was recorded as having a febrile illness which may have contributed to the death. At discharge, which averaged 10 weeks after admission, 22 of the 23 survivors were taking an adequate oral diet. It was also noted that almost half of the patients who wore dentures before the cerebrovascular event were unable to control them afterwards, adding to their neurological swallowing difficulties. The fitting of a PTA and correction of unstable dentures appeared to help both motivation and function. The results show an improvement in the rehabilitation of oral feeding compared with previous reports by other authors, who did not use the dental appliance. There did not appear to be any medical contraindication to its use.

Dysphagia in cerebral palsy: A comparative study of the exeter dysphagia assesment technique and a multidisciplinary assessment

Eighteen children with cerebral palsy in a special school, most of whom had feeding difficulties, were studied to compare the diagnostic value of the Exeter Dysphagia Assessment Technique (EDAT) with an exhaustive clinical assessment undertaken by a multidisciplinary team experienced in the diagnosis and treatment of dysphagia of neurological origin. Four feeding skills were assessed by each method independently, viz. anticipation, intraoral sensory perception, oral-motor efficiency, and pharyngeal triggering. Comparison of the two sets of results showed agreement in at least 78% of the assessed skills. The possible reasons for the few discrepancies are discussed. The noninvasive EDAT equipment was easy to use with the children, who had a range of type and severity of cerebral palsy. The test was undertaken in their familiar surroundings and took 15 to 20 min per child. Interpretation of the results showed that EDAT provided a rapid, reliable diagnostic aid which assisted in the assessment of the degree of feeding impairment within each of the four feeding skills tested.

Ultrasonographic study of sucking and swallowing by newborn infants.

SIRWeber and colleagues (DMCN, 28, 19-24) included in their results on bottle-fed babies a trace (their Fig. 2) drawn from a video screen showing suck-swallow cycles and a respiratory trace recorded from a Graseby Dynamics Apnoea Alarm. Commenting on the co-ordination of swallowing and breathing, the authors state: ‘In some of the babies the swallows occurred consistently in the end-expiratory pause (between expiration and inspiration). This was noted particularly in fourand five-day-old babies. In others, notably babies at two days of age, the breath was held during either inspiration or expiration, in association with a swallowing motion’. In our series of observations on bottle-fed babies, made on a much larger sample than that reported by Weber et al. and using different techniques to record sucking, swallowing and respiration, we have found that the pattern for two-day-old babies is commonly a form which we have called ‘immature’. It later develops, over about five to eight days, into a more ‘mature’ pattern. We were disturbed to find that the patterns we had observed over many measurements did not agree with those of Weber et al. In particular, our recordings show that the swallow of a mature infant is almost always preceded by an inspiration and followed by an expiration. In those cases when swallowing occurs on expiration, the expiratory flow is arrested as a swallow takes place and then ccntinues before an inspiration. We have no record, from over 100 recordings, of an infant swallowing at end-expiration. To confirm our findings we have Fig. 1. Signals from three transducers recorded simultaneously from eight-day-old baby during resting respiration. Upper trace: thermistor anemometer held at naris. Centre trace: pressure drop across naris, indicating direction of nasal airflow. Bottom trace: Graseby Apnoea Monitor output (E = expiration, I = inspiration). Difference in height of anemometer trace is partly due to inhaled air more easily avoiding the transducer.

Objective Measures of Dysphagia Complexity in Children Related to Suckle Feeding Histories, Gestational Ages, and Classification of Their Cerebral Palsy

Data collected during the routine assessment of 117 dysphagic children with cerebral palsy have been related to both suckle feeding histories and gestational ages and to the classification of cerebral palsy. In addition, a concurrent survey involving 281 children with cerebral palsy in special schools was undertaken which revealed that the sample of referred children appeared to be a true representation of a wider population of dysphagic children with cerebral palsy. A Feeding Difficulty Symptom Score (FDSS) describes the severity of swallowing symptoms reported. A numerical Dysphagia Complexity Index (DCI) quantifies numerically the neurological complexity of the swallowing difficulty. The FDSS correlates closely with the DCI. Twenty-seven percent of mothers of the children who were referred for advice on their present swallowing difficulties stated that they recalled no suckle feeding problems. However, there was no difference in the severity of present swallowing difficulties between those infants who suckle fed well and those who experienced severe difficulties. Those referred children with cerebral palsy born at term exhibited more complex later swallowing problems and were more likely to be classified as athetoid than those born preterm.

Non-invasive technique for assessment and management planning of oral-pharyngeal dysphagia in children with cerebral palsy

The non‐invasive Exeter Dysphagia Assessment Technique (EDAT) was evaluated as a method of assessing the aetiology of dysphagia in children with cerebral palsy (CP). Data were collected from a group of 20 typically developing children (nine girls, 11 boys; age range 7 to 14 years) for comparison with 125 dysphagic children with CP (81 boys, 44 girls; age range 1 to 18 years). The swallowing mechanism has been separated into physiological phases: anticipatory, delivery, oral transit, and oral‐pharyngeal. Normal or abnormal function in each phase was recorded and the common causes of any impaired phase were considered, starting with generalized possibilities before focusing on specific parts of swallowing physiology. Data from 125 dysphagic children with CP show marked differences from the data for the typically developing children. Interpreting individual results was valuable in assisting the assessment team to formulate management strategies; two examples are presented. The technique appears to provide a cost‐effective, non‐invasive, and valuable clinical tool.

Superimposition of analogue data onto a video image: a new technique

There are many tools to aid the clinician in making an accurate medical diagnosis including various imaging techniques and recording analogue signals from the patient. A new, inexpensive method of combining a video image and the instantaneous values of analogue waveforms is described here. The system, TVDATA, is reliable, compact and portable and has been successfully used in various clinical situations. The unit requires a standard video source, such as a camera, a TV monitor, a video recorder and the output from the analogue source or sources. The analogue data are converted into a digital signal and then displayed in a convenient part of the screen as a horizontal bar. Two types of data channel are available--uni- and bidirectional. A number of these channels can be used to record different analogue parameters and an inbuilt octal frame counter assists subsequent review of the video record.