Effect of surface sensory and motor electrical stimulation on chronic poststroke oropharyngeal dysfunction

Effect of submental sensitive transcutaneous electrical stimulation on virtual lesions of the oropharyngeal cortex

OBJECTIVE

The aim of this study was to assess the effect of submental sensitive transcutaneous electrical stimulation (SSTES) on pharyngeal cortical representation after the creation of an oropharyngeal cortical virtual lesion in healthy subjects.

METHODS

Motor-evoked potential amplitude of the mylohyoid muscles was measured with transcranial magnetic stimulation (TMS), the oropharyngeal cortex was mapped by cartography, and videofluoroscopic parameters of swallowing function were measured before and after SSTES (at the end of SSTES [0 min] and at 30 and 60 min), after the creation of a cortical virtual lesion (repetitive TMS, 1 Hz, 20 min on the dominant swallowing hemisphere).

RESULTS

Nine subjects completed the study. After 20 min of SSTES, motor-evoked potential amplitude increased (P<0.05), as did swallow reaction time after repetitive TMS, as seen on videofluoroscopy, which was reversed after electrical stimulation. On cortical mapping, the number of points with a cortical response increased in the dominant lesioned hemisphere (P<0.05), remaining constant at 60 min (P<0.05).

CONCLUSION

SSTES may be effective for producing cortical plasticity for mylohyoid muscles and reverses oropharyngeal cortical inhibition in healthy subjects. It could be a simple non-invasive way to treat post-stroke dysphagia.

The effects of surface neuromuscular electrical stimulation on post-stroke dysphagia: a systemic review and meta-analysis

OBJECTIVE

In this study, we intended to evaluate whether swallow treatment with neuromuscular electrical stimulation is superior to that without neuromuscular electrical stimulation, and whether neuromuscular electrical stimulation alone is superior to swallow therapy.

METHODS

We searched the PubMed and Scopus databases from their earliest record to 31 December 2014 for randomized and quasi-randomized controlled trials that used neuromuscular electrical stimulation to treat post-stroke dysphagia. The Jadad scale was used to assess the quality of the included studies. We extracted the mean differences and standard deviation (SD) between baseline and posttreatment or posttreatment mean and SD for selected outcomes measured in the experimental and control groups for subsequent meta-analyses.

RESULTS

Eight studies were identified. For the comparison "swallow treatment with neuromuscular electrical stimulation vs. swallow treatment without neuromuscular electrical stimulation," we found a significant standardized mean difference (SMD) of 1.27 (95% confidence interval (CI) = 0.51-2.02, P = 0.001) with significant heterogeneity (I(2) = 85%). The meta-analysis for the comparison of neuromuscular electrical stimulation alone and swallow therapy demonstrated a non-significant SMD of 0.25 (95% CI = -0.16-0.65, P = 0.23) without significant heterogeneity (I(2) = 16%).

CONCLUSION

Swallow treatment with neuromuscular electrical stimulation seems to be more effective than that without neuromuscular electrical stimulation for post-stroke dysphagia in the short term considering the limited number of studies available. Evidence was insufficient to indicate that neuromuscular electrical stimulation alone was superior to swallow therapy.

Effect of transcutaneous electrical stimulation amplitude on timing of swallow pressure peaks between healthy young and older adults

OBJECTIVES

This study compared the effect of transcutaneous electrical stimulation (TES) amplitude on timing of lingual-palatal and pharyngeal peak pressures during swallowing in healthy younger and older adults.

BACKGROUND

Transcutaneous electrical stimulation amplitude is one parameter that may have different impacts on the neuromotor system and swallowing physiology. One aspect of swallowing physiology influenced by age is the timing of swallowing events. However, the effect of varying TES amplitudes on timing of swallowing physiology is poorly understood, especially in older adults.

MATERIALS AND METHODS

Thirty-four adults (20 younger and 14 older) swallowed 10 ml of nectar-thick liquid under three TES conditions: no stimulation, low-amplitude stimulation and high-amplitude stimulation. TES was delivered by surface electrodes on the anterior neck. Timing of pressure peaks for lingual-palatal contacts and pharyngeal pressures were measured under each condition.

RESULTS

A significant age × stimulation amplitude interaction was identified for the base of tongue (BOT) [F(2,62) = 5.087, p < 0.009] and the hypopharynx (HYPO) [F(2,62) = 3.277, p < 0.044]. At the BOT, low-amplitude TES resulted in slower swallows in the younger adults compared with no TES. In older adults, low-amplitude TES resulted in faster swallows compared with high-amplitude TES. At the HYPO, no significant differences were identified in pressure timing across the three TES amplitudes in both age groups. In each case, low-amplitude TES resulted in faster swallows in older adults compared with younger adults.

CONCLUSIONS

Transcutaneous electrical stimulation influences pharyngeal pressure timing differently in young and old people, which questions the appropriateness of using a 'one-size-fits-all' TES amplitude for rehabilitating people with dysphagia.

Dysphagia: current reality and scope of the problem

Dysphagia is a symptom of swallowing dysfunction that occurs between the mouth and the stomach. Although oropharyngeal dysphagia is a highly prevalent condition (occurring in up to 50% of elderly people and 50% of patients with neurological conditions) and is associated with aspiration, severe nutritional and respiratory complications and even death, most patients are not diagnosed and do not receive any treatment. By contrast, oesophageal dysphagia is less prevalent and less severe, but with better recognized symptoms caused by diseases affecting the enteric nervous system and/or oesophageal muscular layers. Recognition of the clinical relevance and complications of oesophageal and oropharyngeal dysphagia is growing among health-care professionals in many fields. In addition, the emergence of new methods to screen and assess swallow function at both the oropharynx and oesophagus, and marked advances in understanding the pathophysiology of these conditions, is paving the way for a new era of intensive research and active therapeutic strategies for affected patients. Indeed, a unified field of deglutology is developing, with new professional profiles to cover the needs of all patients with dysphagia in a nonfragmented way.