“Tablet devices may alter programmable shunt valve settings,” thus concludes a study just published online in the Journal of Neurosurgery: Pediatrics. Although it may seem far-fetched to study the effect of the small magnets embedded in an iPad on programmable shunt devices used in children to treat hydrocephalus, this study was actually initiated after a 4-month-old girl presented with altered shunt settings, presumably due to her mother holding an iPad while holding her baby at the same time.
Researchers at the University of Michigan studied the effect of the iPad 2, which just like its successor the iPad 3 contains small magnets for proper functioning of the smart cover, on the settings of magnetically programmable shunt devices. These shunt devices regulate the flow of cerebrospinal fluid taking pressure away from the hydrocephalus, and they can be reprogrammed from outside the body by using specialized magnets.
The researchers tested 10 identical Medtronic Strata programmable shunt valves, exposing them for ten seconds to the weak magnetic field of the iPad at distances of less than 1 centimeter, 1 to 2.5 cm, 2.5 to 5 cm, 5 to 10 cm and greater than 10 cm. In total, the valves were tested 100 times for each distance from an iPad 2 with the smart cover closed and 30 times at distances less than 1 cm with the iPad without the cover.
Depending on the distance, the iPad did indeed interfere with the valve settings: at distances between 0 and 1 cm, the settings changed in 58 percent of the valves. At distances between 1 and 2.5 cm this quickly decreased to 5 percent of valves, with only 1 percent of valves affected at distances between 2.5 and 5 cm and none at higher distances. Without the cover, settings changed in 67 percent of the valves at distances of 0 to 1 cm.
The authors conclude that the iPad can be safely used in the vicinity of patients with programmable shunts, but patients and caregivers should be aware of the potential harmful effects when an iPad is placed very near to the shunt. Many more magnets can be found in households which patients and caregivers should be alert of, and as the iPad’s magnetic field is in the same order of strength as these magnets, similar precautions should taken. We are just hoping programmable pacemakers and ICD’s are not affected in a similar way…
Full article in the Journal of Neurosurgery: Pediatrics: Programmable shunt valve affected by exposure to a tablet computer
Medtronic’s brochure, released long before the above mentioned study, warning patients with Strata shunts of the dangers of nearby magnets…