On Cuba, diplomats, ultrasound, and intermodulation distortion.

This paper analyzes how ultrasounds could have unintentionally led to the AP news recordings of metallic sounds heard by diplomats in Cuba. Beginning with screen shots of the acoustic spectral plots from the AP news, we reverse engineered ultrasonic signals that could lead to those outcomes as a result of intermodulation distortion with non-linearity in the acoustic transmission medium. We created a proof of concept ultrasonic device that amplitude modulates a signal over an inaudible ultrasonic carrier. When a second inaudible ultrasonic source interfered with the primary source, intermodulation distortion created audible byproducts that share spectral characteristics with audio from the AP news. Our conclusion is that if ultrasound played a role in harming diplomats in Cuba, then a plausible cause is intermodulation distortion between ultrasonic signals that unintentionally synthesize audible tones. In other words, acoustic interference without malicious intent to cause harm could have led to the audible sensations in Cuba.

Cybersecurity and medical devices: A practical guide for cardiac electrophysiologists.

Medical devices increasingly depend on software. While this expands the ability of devices to perform key therapeutic and diagnostic functions, reliance on software inevitably causes exposure to hazards of security vulnerabilities. This article uses a recent high-profile case example to outline a proactive approach to security awareness that incorporates a scientific, risk-based analysis of security concerns that supports ongoing discussions with patients about their medical devices.

Security and privacy qualities of medical devices: an analysis of FDA postmarket surveillance.

BACKGROUND: Medical devices increasingly depend on computing functions such as wireless communication and Internet connectivity for software-based control of therapies and network-based transmission of patients' stored medical information. These computing capabilities introduce security and privacy risks, yet little is known about the prevalence of such risks within the clinical setting. METHODS: We used three comprehensive, publicly available databases maintained by the Food and Drug Administration (FDA) to evaluate recalls and adverse events related to security and privacy risks of medical devices. RESULTS: Review of weekly enforcement reports identified 1,845 recalls; 605 (32.8%) of these included computers, 35 (1.9%) stored patient data, and 31 (1.7%) were capable of wireless communication. Searches of databases specific to recalls and adverse events identified only one event with a specific connection to security or privacy. Software-related recalls were relatively common, and most (81.8%) mentioned the possibility of upgrades, though only half of these provided specific instructions for the update mechanism. CONCLUSIONS: Our review of recalls and adverse events from federal government databases reveals sharp inconsistencies with databases at individual providers with respect to security and privacy risks. Recalls related to software may increase security risks because of unprotected update and correction mechanisms. To detect signals of security and privacy problems that adversely affect public health, federal postmarket surveillance strategies should rethink how to effectively and efficiently collect data on security and privacy problems in devices that increasingly depend on computing systems susceptible to malware.

Defective retinal depolarizing bipolar cells in regulators of G protein signaling (RGS) 7 and 11 double null mice.

Two members of the R7 subfamily of regulators of G protein signaling, RGS7 and RGS11, are present at dendritic tips of retinal depolarizing bipolar cells (DBCs). Their involvement in the mGluR6/Gα(o)/TRPM1 pathway that mediates DBC light responses has been implicated. However, previous genetic studies employed an RGS7 mutant mouse that is hypomorphic, and hence the exact role of RGS7 in DBCs remains unclear. We have made a true RGS7-null mouse line with exons 6-8 deleted. The RGS7(-/-) mouse is viable and fertile but smaller in body size. Electroretinogram (ERG) b-wave implicit time in young RGS7(-/-) mice is prolonged at eye opening, but the phenotype disappears at 2 months of age. Expression levels of RGS6 and RGS11 are unchanged in RGS7(-/-) retina, but the Gß5S level is significantly reduced. By characterizing a complete RGS7 and RGS11 double knock-out (711dKO) mouse line, we found that Gß5S expression in the retinal outer plexiform layer is eliminated, as is the ERG b-wave. Ultrastructural defects akin to those of Gß5(-/-) mice are evident in 711dKO mice. In retinas of mice lacking RGS6, RGS7, and RGS11, Gß5S is undetectable, whereas levels of the photoreceptor-specific Gß5L remain unchanged. Whereas RGS6 alone sustains a significant amount of Gß5S expression in retina, the DBC-related defects in Gß5(-/-) mice are caused solely by a combined loss of RGS7 and RGS11. Our data support the notion that the role of Gß5 in the retina, and likely in the entire nervous system, is mediated exclusively by R7 RGS proteins.

Clinically significant magnetic interference of implanted cardiac devices by portable headphones.

BACKGROUND: Little is known about the magnetic field strength of portable headphones and their potential to cause magnetic interference with implanted pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). OBJECTIVE: The purpose of this study was to evaluate the magnetic field strength of portable headphones and to determine if they can cause clinically relevant magnetic interference. METHODS: PM or ICD function was assessed in 100 patients during exposure to eight different models of portable headphones to determine the incidence of clinically relevant magnetic interference. The magnetic field strength of the headphones also was measured in vitro. RESULTS: Clinically relevant magnetic interference from portable headphones occurred in 30 (30%) of 100 patients and more commonly affected ICD than PM patients (21/55 [38.2%] vs 9/45 [20.0%]; P = .048). All patients affected by magnetic interference experienced a magnet response, characterized by asynchronous pacing in PM patients and by inhibition of tachyarrhythmia detection in ICD patients. In all but one of the 30 cases of magnetic interference, removal of the headphones from the patient's chest immediately restored normal device function. Headphones with a measured magnetic field strength > or =10 gauss at 2 cm were much more likely to cause magnetic interference than were those with lower magnetic field strength (30/100 [30%] patients vs 0/100 [0%] patients; P <.0001). Magnetic interference was not observed when headphones were placed > or =3 cm from the skin surface. CONCLUSION: Clinically significant magnetic interference can occur when portable headphones are placed in close proximity to implanted PMs and ICDs. Patients with such a device should be advised to keep portable headphones at least 3 cm from their device.