Isolated cochlear neuritis from varicella reactivation mimicking a vestibular schwannoma.

We present a case of a patient with progressive unilateral sensorineural hearing loss and tinnitus with internal auditory canal enhancement on magnetic resonance imaging (MRI) secondary to isolated cochlear neuritis from varicella reactivation. MRI following antiviral treatment showed resolution of enhancement. Varicella reactivation is commonly seen in the form of Ramsay Hunt syndrome, which is known to produce abnormal MRI enhancement from facial and vestibulocochlear neuritis; however, its characteristic clinical signs aid the diagnosis. This case is unique in that the only manifestation of varicella infection was unilateral hearing loss. This case outlines the importance of maintaining a broad differential diagnosis in the evaluation of unilateral hearing loss as well as recognizing the limited specificity of MRI.

Detection of small bowel slow-wave frequencies from noninvasive biomagnetic measurements.

We report a novel method for identifying the small intestine electrical activity slow-wave frequencies (SWFs) from noninvasive biomagnetic measurements. Superconducting quantum interference device magnetometer measurements are preprocessed to remove baseline drift and high-frequency noise. Subsequently, the underlying source signals are separated using the well-known second-order blind identification (SOBI) algorithm. A simple classification scheme identifies and assigns some of the SOBI components to a section of small bowel. SWFs were clearly identified in 10 out of 12 test subjects to within 0.09-0.25 cycles per minute. The method is sensitive at the 40.3 %-55.9 % level, while false positive rates were 0 %-8.6 %. This technique could potentially be used to help diagnose gastrointestinal ailments and obviate some exploratory surgeries.

Noninvasive detection of small bowel electrical activity from SQUID magnetometer measurements using SOBI.

We report a robust method for noninvasive biomagnetic detection of small bowel electrical activity. Simultaneous Superconducting QUantum Interference Device (SQUID) magnetometer (MENG) and serosal electrode recordings were made on pig small bowel. The SOBI blind-source separation algorithm was used to separate the underlying source signals of the MENG. Comparison of identified SOBI components to the serosal recordings validated the underlying MENG sources as being enteric in origin. Non-invasive detection of small bowel electrical activity could have significant implications in a clinical setting.