Oropharyngeal dysphagia in amyotrophic lateral sclerosis: neurological and dysphagia specific rating scales

BACKGROUND: Oropharyngeal dysphagia is highly prevalent in amyotrophic lateral sclerosis (ALS). Patients with dysphagia and weight loss are frequently offered gastrostomy. Although the neurological basis of dysphagia in ALS is complex, there are currently no specifically validated scales for dysphagia in ALS, and the reliability of existing generic scales has not been assessed. METHODS: We undertook a prospective study of 25 patients who fulfilled the criteria for definite or probable ALS. We examined the reliability of the Dysphagia Outcome Severity Scale ( DOSS) and the Aspiration-Penetration Rating Scale (APRS) and the correlation between these scales and the Norris ALS Scale and ALS Functional Rating Scale-R ( ALS FRS-R). RESULTS: Using the Pearson Product-Moment Correlation, an expected high linear association between the two disease specific neurological scales was demonstrated. Both dysphagia scales were found to be reliable. Interrelationship evaluation showed a low association between Norris and ALS FRS-R scores and DOSS and APRS. However, examination found specific subsections to be significantly correlated, particularly the Norris bulbar sections (NBS) and the DOSS. CONCLUSIONS: Generic dysphagia scales are reliable indicators of dysphagia in ALS. The bulbar components of the ALS specific scales is sensitive to dysphagia. The bulbar section of the Norris scale can be utilised as an independent and reliable indicator of the severity of dysphagia in ALS. In the absence of availability of detailed swallowing assessment using videofluoroscopy, these scales, i.e., the Norris and to a lesser degree the ALS FRS-R bulbar sections, are adequate to diagnose and follow clinically significant dysphagia in ALS, and can be used as an indicator for dysphagia treatment initiation.