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Hilger info sheet (.pdf format)

Hilger Facial Nerve Stimulator
Model H3

	The Original Facial Nerve Stimulator
	Designed for Clinical Testing of Facial Nerve Paralysis

The Hilger Facial Nerve Stimulator is designed for clinical testing of facial paralysis. Low-energy, square-wave current is applied to the skin overlying the facial nerve trunk (or branches) using the bipolar probe. Nerve response is indicated by twitching of the associated facial muscles. Degeneration of nerve fibers on the paralyzed side is evidenced by a weaker response to a given current intensity than that given by the normal side, or by a higher current being required to produce an equivalent response. Absence of response at high current settings indicates complete nerve degeneration.
     In the Minimal Stimulation Test, the current is turned up until the onset of twitching of one or more of the facial muscles. The normal side usually responds at about 3 milliamperes (mA), and a higher setting required to produce a response on the paralyzed side indicates nerve degeneration. The difference between the two sides shows the extent of degeneration.
     In the Maximal Stimulation Test, the current is set at about 5 mA, which is sufficient to fire all of the viable nerve fibers and produce maximum contractions. The observed strength of the muscle contractions on the paralyzed side compared to those of the normal side indicates the relative number of nerve fibers responding to stimulation and the degree of nerve degeneration.

Use of the Hilger in NET and MST versus ENOG:

There is some debate about the ability of ENOG  (electroneurography) and MST/NET (Hilger Tests: MST = Maximal Stimulation Test, NET = Nerve Excitability Threshold) to predict prognosis in patients with facial nerve paralysis. Research has provided some direction on the question:

• "ENOG is a less accurate measure of the state of the facial nerve than is MST, and selecting patients for facial nerve surgery on the basis of ENOG results would be hazardous." (From "Who's Afraid of the Facial Nerve," Kedar Adour, MD; see references.)
• "Facial nerve conduction latency (ENOG) is a less accurate indicator of prognosis in Bell's Palsy. Furthermore, latency cannot indicate axonal degeneration before other currently used electrodiagnostic tests." (From "The Maximal Stimulation and Facial Nerve Conduction Latency Tests: Predicting the Outcome of Bell's Palsy," John Ruboyianes, MD, and Kedar Adour, MD; see references.)
• "The sensitivity of NET is 85 percent, MST is 79 percent, and EnoG is 89 percent. The specificity of NET is 87 percent, MST is 93 percent, and EnoG is 57 percent." (From "Nerve Excitability Testing: Technical Pitfalls and Thresholds Norms Using Absolute Values," George Gates, MD; see references.)

Features:

• Safe, Low Energy, Precise Current Control: Constant current, pulsed stimulation eliminates the hazards of non-pulsed or constant voltage stimulation methods.
• Shatterproof Case: High impact ABS material withstands accidental abuse.
• Easy-to-Read Battery Status Indicator: Low battery monitor lets operator know when batteries need replacing.
• Special Skin Resistance Compensating Circuitry: Automatically adjusts for varying skin resistance to provide accurate stimulation levels.
• Adjustable Bipolar Probe: Conveniently adjusts for each patient. Soft-touch tactile button provides additional comfort for the operator.
• Easy-to-Read Backlit LCD Display: Allows the operator to easily and conveniently see and adjust the stimulating current.

Current Characteristics:

The Hilger Model H3 uses pulsed, constant-current stimulation, which is safer than most constant-voltage or non-pulsed DC stimulators. The Hilger Model H3 allows direct stimulation of nerve tissue without risk of injury. Special circuitry automatically adjusts for varying skin resistance to provide accurate stimulation levels.

Technical Specifications:

• Current output: 0 to 10 mA, residual current of 0.05 mA at 0 indicated
• Pulse width: 0.0006 seconds
• Pulse off time: 0.1660 seconds
• Pulse frequency: 0.1666 seconds
• Dial accuracy: Linear down to 0.15 mA, residual current of 0.05 mA at 0 indicated
• Batteries: four 1.5-volt Alkaline C cells
• Battery life: 200 hours continuous use between replacement
• Size: 8.5 x 9 x 3 inches (21.6 x 22.8 x 7.6 cm)
• Weight: 4 pounds (1.82 kg)

Furnished Accessories:

Please ask for our current price list for latest selection.

Notes:

• The Hilger is not recommended for use in surgery.
• Please go to the Silverstein Facial Nerve Stimulator/Monitor, or Brackmann II EMG System pages for devices suitable for use in surgery.

Quality and Safety Marks

• ISO 9001:2000, ISO 13485:1996, and MDD compliant
• See latest regulatory certifications