Psychometric assessment and validation of the dysphagia severity rating scale in stroke patients

Abstract

Post stroke dysphagia (PSD) is common and associated with poor outcome. The Dysphagia Severity Rating Scale (DSRS), which grades how severe dysphagia is based on fluid and diet modification and supervision requirements for feeding, is used for clinical research but has limited published validation information. Multiple approaches were taken to validate the DSRS, including concurrent- and predictive criterion validity, internal consistency, inter- and intra-rater reliability and sensitivity to change. This was done using data from four studies involving pharyngeal electrical stimulation in acute stroke patients with dysphagia, an individual patient data meta-analysis and unpublished studies (NCT03499574, NCT03700853). In addition, consensual- and content validity and the Minimal Clinically Important Difference (MCID) were assessed using anonymous surveys sent to UK-based Speech and Language Therapists (SLTs). Scores for consensual validity were mostly moderate (62.5–78%) to high or excellent (89–100%) for most scenarios. All but two assessments of content validity were excellent. In concurrent criterion validity assessments, DSRS was most closely associated with measures of radiological aspiration (penetration aspiration scale, Spearman rank rs = 0.49, p < 0.001) and swallowing (functional oral intake scale, FOIS, rs = −0.96, p < 0.001); weaker but statistically significant associations were seen with impairment, disability and dependency. A similar pattern of relationships was seen for predictive criterion validity. Internal consistency (Cronbach’s alpha) was either “good” or “excellent”. Intra and inter-rater reliability were largely “excellent” (intraclass correlation >0.90). DSRS was sensitive to positive change during recovery (medians: 7, 4 and 1 at baseline and 2 and 13 weeks respectively) and in response to an intervention, pharyngeal electrical stimulation, in a published meta-analysis. The MCID was 1.0 and DSRS and FOIS scores may be estimated from each other. The DSRS appears to be a valid tool for grading the severity of swallowing impairment in patients with post stroke dysphagia and is appropriate for use in clinical research and clinical service delivery.

Pharyngeal electrical stimulation for neurogenic dysphagia following stroke, traumatic brain injury or other causes: Main results from the PHADER cohort study

“…The difference between PHADER and STEPS appeared to be developing by the second week after treatment with a difference of over 1·0 point. Both differences equal or exceed the minimum clinical important difference for DSRS, which is 1 [6] , and so can be considered to be clinically relevant. Two explanations may be relevant; first, clinical measures such as DSRS may lag in detecting improvements in dysphagia (see limitations below for an expanded discussion of this issue) and so assessment within two weeks may be too early.…”

“…Since it is the same pathways being damaged, PES targets the resulting dysphagia rather than the initial causative disease. Hence, the primary objective of the study was to assess the real-world effect of PES on dysphagia severity (assessed using the validated dysphagia severity rating scale, DSRS [ 4 , 6 ]) in patients with neurogenic dysphagia. Secondary objectives assessed the effect of PES on penetration/aspiration (PAS [7] ) determined using instrumental-testing; feasibility, tolerability and safety of PES; and its ease of use.…”

“…The primary outcome measure was the validated 13-level DSRS score [ 4 , 6 ] at 3 months post-treatment. Secondary outcomes comprised dysphagia severity assessed using the functional oral intake scale (FOIS) [13] , and penetration-aspiration assessed with the PAS [7] measured instrumentally (using videofluoroscopy (VFS) or fibreoptic endoscopic evaluation of swallowing (FEES)).…”

“…Pharyngeal electrical stimulation (PES) is a potential treatment for neurogenic dysphagia based on physiological studies [3] . PES has been studied in several phase II trials in patients with PSD [ 4 , 5 ] and was associated with less dysphagia (assessed using the dysphagia severity rating scale, DSRS [ 4 , 6 ]) and instrumentally-assessed penetration/aspiration (penetration aspiration scale, PAS [7] ) in an individual-patient data meta-analysis [8] . However, a phase III trial of PES for PSD was neutral on PAS and DSRS, possibly because dysphagia was mild at baseline, the active group were undertreated and the sham group received some treatment [9] .…”

Successful treatment of intubation-induced severe neurogenic post-extubation dysphagia using pharyngeal electrical stimulation in a COVID-19 survivor: a case report

“…These assessments were performed initially at bedside; they revealed oral and suspected pharyngeal swallowing dysfunction manifest as poor saliva management with observed drooling, suspected reduced hyolaryngeal elevation as judged via palpation during volitional swallowing, and aphonia. Consequently, “nil by mouth” was recommended by the speech and language therapist (SLT) (Dysphagia Severity Rating Scale score [ 23 ], DSRS = 12; Functional Oral Intake Scale score [ 24 ], FOIS = 1). Due to the COVID-19 pandemic and restrictions on the conduct of aerosol-generating procedures, the SLT was unable to complete an instrumental assessment of the swallow, such as a fibreoptic endoscopic evaluation of swallowing (FEES) or videofluoroscopy (VFS), to more directly assess the patient’s oropharyngeal swallowing function.…”