Aiming at a protocol: a review of functional scales pertaining to cranial neuropathies in skull base phatology

Abstract

The cranial nerves play a pivotal role in various physiological functions, and their impairment is a prevalent and impactful occurrence. The main aim of this study was to assess the available literature for Clinical Functional Scales usable for the diagnosis, assessment, and follow-up of cranial neuropathies, potentially to apply them in a standardized patient follow-up protocol. A comprehensive search was conducted through the PubMed search engine, using twelve queries composed of "(functional scale OR functional score OR grading scale OR grading system) AND", followed by each one of the cranial nerves. The articles obtained were then screened to confirm their correspondence to either the description, employment and/or validation of nerve-specific clinical/functional scales. The results of interest were gathered, and their references and of other relevant articles mentioned, collected. The availability of functional scales varied a lot according to the cranial nerve. No pertinent scales were found for cranial nerves IV, VIII, IX, X and XII. For cranial nerves I, II, III, V, VI, VII and XI, grading methods were found that were considered at least partially relevant according to the defined criteria. Despite the critical importance of the cranial neurologic examination in medical practice, the tools available for cranial nerves' basic clinical assessment and scoring remain scarce. There is a big disparity in existence of functional scales for the different cranial nerves, with some lacking appropriate individual scoring methods altogether. This highlights the need for further research on the topic, and for the development of protocols and scales tailored to each cranial nerve. This study aims to stimulate future efforts towards addressing this gap found in cranial neuropathies' clinical assessment.