Method and apparatus for treating poor laryngeal-elevation disorder with sequential-high voltage electrical stimulation

• US 6,484,053 B2
• Filed: 11/29/2000
• Issued: 11/19/2002
• Est. Priority Date: 11/29/2000
• Status: Expired due to Fees

• Current Assignee: National Science and Technology Development Agency
• Original Assignee: Pairash Thajchayapong
• Inventors: Geater, Alan, Limsakul, Chusak, Leelamanit, Vitoon
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/725,055
• Publication Number:
  US 20020133194A1
• Time in Patent Office: 720 Days
• Field of Search: 600/546, 600/593, 600/595, 607/2, 607/40, 607/72, 607/48, 607/62
• US Class Current: 607/2
• CPC Class Codes: A61B 5/4205 Evaluating swallowing
• CPC Class Codes: A61N 1/36007 of urogenital or gastrointestinal organs, e.g. for incontinence control
• CPC Class Codes: A61N 1/3601 of respiratory organs
• CPC Class Codes: A61N 1/36031 using physiological parameters for adjustment
• CPC Class Codes: A61N 1/36034 specified by the stimulation parameters

Abstract

The sequential stimulator for the treatment of dysphagic patients incorporates a unit which is capable of detecting a swallowing signal from the glossal or temporalis surface electromyography (SEMG). When a swallowing signal is recognized, a trigger signal is sent to the stimulation generation unit to release high voltage stimuli sequentially to the suprahyoid muscles or the masseter muscles and the pharyngeal muscles in order to assist in the elevation of the larynx. This enables the pharyngeal lumen to open more widely so that food can pass through the patient'"'"'s pharynx and into the oesophagus more easily during swallowing. Thus the sequential stimulator is a device for assisting swallowing in patients with dysphagia due to a variety of causes, for instance, brain injury, cerebrovascular accident, injury of the cervical nerves, muscles weakness, or old age. The stimulator is operative only when the patient attempts to swallow and provides a physiologic stimulus and provides a means of immediate relief of the swallowing difficulty. The device is also useful for physical therapy whereby the muscles under the chin, the masseter muscles and the pharyngeal muscles can be re-educated to contract in the normal coordinated sequence.

Claims

1. A method for treating a dysphagic patient using variable high voltage sequential electrical stimulation comprising the steps of:

detecting a swallowing signal from the SEMG of the glossal or temporalis muscle of the patient during a swallowing event with at least a pair of electrodes placed bilaterally on the skin in the region of the submandibular salivary glands of the patient or bilaterally in the temporal area, and a ground electrode placed on the inner right forearm of the patient;

processing the signal from the electrodes with a signal processing circuit for amplifying and passing the signal to a calculation and comparator circuit;

calculating the signal and comparing the signal with the calculation and comparator circuit using a reference to determine whether the patient is attempting to swallow, whereby an attempted swallow is recognised and a signal will be sent to a stimulation generation circuit to deliver high voltage stimuli to the patient'"'"'s muscles under the chin and of the pharynx via stimulation electrodes placed under the chin and on the pharynx of the patient; and

generating high voltage by the stimulation generation circuit which delivers high voltage stimuli to the patient'"'"'s muscles under the chin and pharyngeal muscles via electrodes connected to at least one channel.

2. The method for treating a dysphagic patient using variable high voltage sequential electrical stimulation according to claim 1, wherein said electrodes connected to more than one channel and the stimulus in the channels are sent simultaneously.

3. The method for treating a dysphagic patient using variable high voltage sequential electrical stimulation according to claim 1 wherein the step of performing and calculating the signal includes the steps of:

performing a calculation to determine the power of the signal of the glossal muscles of the patient with the following equation;

$P=\frac{1}{\left(4.7<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}\right)}<br><br>{\int <br><br>}_0^t<br><br>v^2<br><br><br><br>t$

Wherein P is the power of the signal from the glossal or temporalis muscles, v is the amplitude of the SEMG signal after passing through the signal processing circuit, and t is the time, ranging from 60-120 ms.;

comparing the power signal P with a reference voltage, which is adjustable over the range 0-2 volts; and

generating an adjustable pulse signal of width 1-3 seconds if said calculated power signal has a value higher than said reference voltage.

4. The method for treating a dysphagic patient using variable high voltage sequential electrical stimulation of claim 3 further comprising the step of:

sending the adjustable pulse signal to said stimulation generation circuit to activate the stimulation generation circuit and stop operation of the calculation and comparator circuit during the generation of the stimulus.

5. The method for treating a dysphagic patient using variable high voltage sequential electrical stimulation according to claim 1 further comprising the step of:

sending the adjustable pulse signal to said stimulation generation circuit to activate the stimulation generation circuit and stop operation of the calculation and comparator circuit during the generation of the stimulus.

6. A sequential electrical stimulator comprising:

a detecting swallowing signal circuit for detecting the signal from the SEMG of the glossal or temporalis muscle of a patient during a swallowing event with at least a pair of electrodes placed bilaterally on the skin in the region of the submandibular salivary glands of the patient or bilaterally in the temporal area, and a ground electrode placed on the inner right forearm of the patient;

a signal processing circuit for amplifying and passing the signal to the calculation and comparator circuit;

a calculation and comparator circuit for performing calculation and comparison for performing a calculation to determine the power of the signal of the glossal muscles of the patient with the following equation;

$P=\frac{1}{\left(4.7<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}\right)}<br><br>{\int <br><br>}_0^t<br><br>v^2<br><br><br><br>t$

wherein P is the power of the signal from the glossal or temporalis muscles, v is the amplitude of the SEMG signal after passing through the signal processing circuit, and t is the time ranging from 60-120 ms., comparing the power signal P with a reference voltage, which is adjustable over the range 0-2 volts, and generating an adjustable pulse signal of width 1-3 seconds if said calculated power signal has a value higher than said reference voltage; and

a stimulation generation circuit having at least 2 or more output channels generating a high-voltage twin-peak pulse signal of width 75 s and frequency 40-80 Hz with a gradually increasing amplitude until the constant value is reached after 250 ms to the patient'"'"'s under chin muscles and pharyngeal muscles via electrodes connected to several different channels or at least one output channel.

7. The sequential electrical stimulator according to claim 6, wherein the stimulus signal in one of the channels is delayed by between 0-120 ms after the stimulus signal in one other channel.

8. The sequential electrical stimulator according to claim 7, wherein the high-voltage twin-peak stimulation generation circuit generates stimulation signals in each channel with variable speeds.

9. The sequential electrical stimulator according to claim 6, wherein the high-voltage twin-peak stimulation generation circuit has at least two channels.

10. The sequential electrical stimulator according to claim 9, wherein each of the channels delivers stimulation signals no faster than one per 120 ms.

11. The sequential electrical stimulator according to claim 10, wherein the high-voltage twin-peak stimulation generation circuit generates stimulation signals in each channel with variable speeds.

12. The sequential electrical stimulator according to claim 9, wherein the high-voltage twin-peak stimulation generation circuit generates stimulation signals in each channel with variable speeds.

13. The sequential electrical stimulator according to claim 6, wherein the high-voltage twin-peak stimulation generation circuit generates stimulation signals in each channel with variable speeds.

14. The sequential electrical stimulator according to claim 6, further comprising a circuit by-pass control button for generating a stimulation signal.

15. The sequential electrical stimulator according to claim 6 wherein said at least a pair of electrodes composed of rubber-carbon composite for stimulating dysphagic patients placed on the skin under the chin in the midline (submental region) separated by a distance of 0.5-1.5 cm.

16. The sequential electrical stimulator according to claim 6 wherein said at least a pair of electrodes composed of rubber-carbon composite for stimulating the thyrohyoid muscle and placed bilaterally on the skin at the wings of the larynx (thyroid cartilage) with the upper edge of the electrodes below the hyoid bone.

17. The sequential electrical stimulator according to claim 6 wherein said at least a pair of electrodes composed of rubber-carbon composite for stimulating the thyrohyoid muscle placed bilaterally on the skin at the wings of the larynx (thyroid cartilage) separated by a distance of 0.5-1.5 cm with the upper edge of the electrodes below the hyoid bone.

18. The sequential electrical stimulator according to claim 6 wherein said at least a pair of electrodes composed of rubber-carbon composite for stimulating the masseter muscles placed bilaterally on the skin of the cheeks in the region of the ascending ramus of the mandible.