User Experience Network [Health Devices Jan-Feb 1999;28(1-2):81-2]
Occasionally, pediatric patients and
younger visitors to the hospital bring a toy called a Furby with them into the
facility. Because these toys are mechanized and can transmit infrared signals,
some of our clinical staff have expressed concern that the toy may interfere
with medical equipment. Is this a valid concern?
We believe that interference with medical equipment by a Furby toy is highly unlikely. Thus, although the possibility of interference cannot be completely
ruled out, we believe that banning these toys from the hospital is unnecessary.
The Furby is a small,
microprocessor-controlled stuffed animal manufactured by Tiger Electronics Ltd.
(a division of Hasbro) for children aged six and older. The toy can move its
eyes, mouth, and ears using a small electric motor powered by four AA batteries.
These batteries also power various sensors and two small microprocessors that
control the Furby. The Furby has a number of automated capabilities—for
example, it moves and talks in response to sounds in its vicinity, it imitates
certain sounds, and it can simulate conversation with other Furbies. To perform
this last function, Furbies exchange short infrared signals.
Some hospitals have expressed concern
that the Furby's motor, microprocessors, or infrared transmitter may cause
interference with medical devices. However, we believe there is no significant
risk of this happening. Since November 1998, when the Furby was first sold, ECRI
has received no reports of medical device interference or malfunction attributed
to the toy. In addition, we have researched certain aspects of the Furby's
operation—this included performing some tests—and believe the toy is
unlikely to cause problems in hospitals. Unfortunately, the concerns about the
Furby have created excessive media attention, and some hospitals have reacted by
needlessly banning the toy.
The two specific areas that have
provoked concern are the production of electromagnetic noise by the Furby's
motor and microprocessors and the toy's use of infrared signals. Our
investigation of these areas is discussed below.
We investigated the Furby's
electromagnetic noise production using a spectrum analyzer and found that the
toy does produce electromagnetic noise over the frequency range of the spectrum
analyzer (up to 500 MHz). However, the noise appears to be of low amplitude, and
it quickly diminishes when the Furby is moved away from the analyzer. We also
placed the toy directly alongside the transmitters and receivers of two
different telemetry systems, with each system transmitting and displaying a
simulated ECG signal. We did not detect any distortion in the ECG signals.
To cause a medical device to
malfunction, the electromagnetic fields generated by the toy would need to be
strong enough to interrupt or distort electronic signals in other electronic
devices, or to generate additional signals detected by those devices. Although
the Furby produces a small amount of electromagnetic noise, we believe that this
noise is of insufficient amplitude to interfere significantly with medical
devices, even those in the toy's immediate vicinity.
Within a hospital, three types of
medical devices that use infrared signals are commonly encountered: certain
operating room (OR) equipment, nurse call systems, and pulse oximeters.
OR equipment. It is highly unlikely
that a Furby would be found in an OR. Therefore, we did not investigate the
toy's effects on the infrared-based functions of equipment used in this
Nurse call systems. Although nurse
call systems use infrared signals, those signals are very different from the
ones produced by a Furby. A Furby generates an infrared pulse by switching its
infrared emitter on and off only once. On the other hand, during each pulse
produced by a nurse call system, the infrared emitter is turned on and off many
times, at a very high frequency (in the kilohertz range). The infrared receptors
of nurse call systems are designed to recognize these high-frequency pulses and
would be unlikely to respond to the type of signal produced by a
Pulse oximeters. We tested the
effect of the Furby's infrared signal on pulse oximeters by placing the toy's
infrared transmitter directly alongside the reusable probe of a pulse oximeter
being used on a human subject. (We employed a reusable probe because it is more
likely to be susceptible to infrared interference.) The probe clamps to the top
and bottom of a subject's finger, with its light detector on the underside. We
positioned the Furby above and to the side of the subject's finger so the
infrared signal could pass through the finger and strike the light
We performed this test twice, each time using a different pulse oximeter. We did not detect any changes in the pulse oximeters' SpO2 values or pulse measurements
while the toy emitted infrared signals. This was most likely because the toy's
pulses were too infrequent to affect the pulse oximeter, which generally
averages its measurements over several seconds.
Some hospitals may believe that it is
best to ban the Furby to eliminate any risk of interference with medical
equipment. In our opinion, such a ban is unnecessary. The Furby, like any other
toy, may have a calming effect on a child being treated in the hospital. Given
that a Furby's electromagnetic output is small and that its infrared emissions
involve a simple pulsing scheme, ECRI considers it safe to allow Furby toys into
the hospital, even in the immediate vicinity of medical equipment. In the
unlikely event that a Furby does produce interference, we urge any healthcare
institution experiencing such a problem to contact ECRI.
- Nurse Call Systems [15-614]
- Oximeters, Pulse [17-148]
- Oximeters, Pulse, Telemetric
Cause of Device-Related Incident
Device factor: Device interaction
External factor: Electromagnetic or
radio-frequency interference (EMI and RFI)
Mechanism of Injury or Death
Failure to deliver therapy; Monitoring