A REVIEW OF ELECTRICAL STIMULATION AND ITS EFFECT ON LINGUAL, LABIAL AND BUCCAL MUSCLE STRENGTH.

Background: Lingual, labial and buccal weakness (LLBW) is a widespread consequence of several neurological insults. LLBW impact on oral motor functions such as speech production and swallowing is well documented in the literature. Therefore, it is important for the speech-language pathologists to have access to evidence-based approaches for treatment. Thus, it is imperative that the speech-language pathology field search for effective treatment approaches and explore new treatment modalities that can improve therapy outcomes. One relatively new modality in this field is neuromuscular electrical stimulation (NMES).

Aims: The purpose of this paper is fivefold: (a) to provide an overview of the general effects of NMES on skeletal muscles; (b) to review the effect of NMES on orofacial musculature evaluating the potential appropriateness of NMES for use in strengthening lingual, labial and buccal muscles; (c) to identify future directions for research with consideration of its potential role in improving speech intelligibility and the oral preparatory phase of swallowing in patients with oral motor weakness; (d) to provide a brief anatomic and physiologic bases of LLBW; (e) to provide background information for orofacial myologists who may encounter individuals with LLBW.

Main contribution: NMES is a modality that is commonly used in physical therapy and occupational therapy fields that assists in treating several motor and sensory muscular disorders including muscular weakness. The literature reviewed demonstrate that very limited data related to the use of NMES on orofacial muscles exist despite the fact that these muscles can be easily accessed by electrical stimulation from the surface.

Conclusions: This review of the research using electrical stimulation of muscles highlights the need for experimental treatment studies that investigate the effect of NMES on orofacial weakness.