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30-06-2011 | Article

IFC stimulation effective for treating pharyngeal dysphagia


Free abstract

MedWire News: Inferential electrical current (IFC) stimulation increases swallowing frequency in patients with pharyngeal dysphagia, research shows.

"IFC stimulation at the sensory threshold with 50-Hz modulation significantly increased the number of swallows without any discomfort," report Yoshitaka Oku (Hyogo College of Medicine, Japan) and colleagues in the journal Dysphagia.

The risk of developing a swallowing disorder increases as individuals get older, and this risk increases further in patients with cerebrovascular and neuromuscular diseases.

Postural techniques, dietary changes, and swallowing maneuvers have been used in the past to treat those with swallowing difficulties, but electrical stimulation has received attention as an option for pharyngeal dysphagia.

In past studies, researchers have tested a pulsed current at 1-120 Hz to treat dysphagia, but these frequencies caused patient discomfort.

Oku and colleagues therefore tested kilohertz-frequency alternating currents (ACs) in 10 healthy individuals.

The IFC used in the trial comprised two independent kilohertz-frequency ACs of constant intensity applied by pairs of electrodes and placed diagonally on the neck of the patient.

Compared with participants who underwent stimulation with a pure 2000-Hz AC, those who received 2000-Hz AC with a 50-Hz amplitude modulation had significantly increased swallowing frequency.

There was a statistically significant difference between the two treatments during the 5-minute stimulation period.

"Pure AC stimulation did not affect the number of swallows per a given time, suggesting that a low-frequency amplitude modulation is required for the facilitation of swallowing behavior," state the researchers.

For the within-group differences, there was an increase in swallowing frequency from baseline in those who received IFC stimulation.

The facilitating effect of treatment was maintained without any discomfort during the 15-minute stimulation, "suggesting that a prolonged stimulation is feasible and effective," say the investigators.

The effect disappeared when the IFC was stopped, with no statistically significant difference observed between treatments 5 minutes after stimulation.

Amplitude-modulated kilohertz-frequency AC stimulation is a possible alternative, and more comfortable method, of providing therapeutic electrical neural stimulation in patients with pharyngeal dysphagia, conclude the researchers.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

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