IOPI System: Iowa Oral Performance Instrument
Swallowing Therapy With Measurable Results
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How does the IOPI measure strength?
How does the IOPI measure endurance?
How is the IOPI used for exercise therapy?

What It Does and How It Helps

The Iowa Oral Performance Instrument (IOPI) objectively measures:
These measures aid professionals involved in the treatment and study of disorders affecting swallowing, speech, and eating by:
  • objectively documenting deficits that justify treatment
  • diagnostically differentiating between muscle weakness and problems of motor control
  • providing biofeedback during isometric oral motor exercise programs
  • motivating patients by showing them their progress from muscle exercise therapy.

How It Works

How does the IOPI measure strength?

The IOPI measures the strength of the tongue by measuring the maximum pressure that an individual can produce in a disposable standard-sized tongue bulb by pressing the bulb against the roof of the mouth with the tongue. The peak pressure achieved is displayed on a large, easy-to-read LCD. The units displayed are kilopascals (kPa), based on the internationally-recognized unit of pressure, the Pascal (Pa).

The IOPI® has been validated in many scientific studies, and normal standards exist for tongue elevation strength.
Lip compression strength depends on the strength of the circumferential muscle complex that surrounds the mouth. It is the tension in these muscles that allows the lips to be compressed against one another. The bulb, placed between the lips or under the cheek at the corner of the mouth, measures the maximum pressure created when a patient presses their lips together or “purses” as hard as they can.

How does the IOPI measure endurance?

In patients with dysphagia or dysarthria, oral motor fatigability may be of interest. The IOPI can be used to assess tongue fatigability by measuring its endurance, which is inversely proportional to fatigability. Low endurance values are an indicator of a high fatigability.

Endurance is measured with the IOPI by quantifying the length of time that a patient can maintain 50% of his or her Peak pressure. This procedure is conducted by setting the maximum pressure in the Lights Mode to 50% of the patient’s Peak pressure and timing how long the patient can hold the top (green) light on.

How is the IOPI used for exercise therapy?

The IOPI has a vertical row of lights (LEDs) on the front. The higher the pressure, the higher the position of the light that is turned on. Producing a pressure that can turn on the top (green) light can be thought of as “winning”(“I hit the target!”). The pressure required to illuminate the green light at the top of the IOPI’s light array can be adjusted using the Set Max arrow buttons. The medical professional determines what target value is appropriate for exercise therapy purposes and provides specific instructions to the patient for a particular exercise protocol. A protocol should include the target value to set, the number of times to illuminate the green light and, for each repetition, how long the green light should be illuminated before releasing pressure on the bulb.

Setting the target value can be expressed algebraically:

T = Pmax x (E/100) where
T= Target value, Pmax = Peak tongue pressure, E = Effort (%)