Tinnitus and auditory cortex; Using adapted functional near-infrared-spectroscopy to expand brain imaging in humans.

OBJECTIVES: Phantom sound perception (tinnitus) may arise from altered brain activity within auditory cortex. Auditory cortex neurons in tinnitus animal models show increased spontaneous firing rates. This may be a core characteristic of tinnitus. Functional near-infrared spectroscopy (fNIRS) has shown similar findings in human auditory cortex. Current fNIRS approaches with cap recordings are limited to ∼3 cm depth of signal penetration due to the skull thickness. To address this limitation, we present an innovative fNIRS approach via probes adapted to the external auditory canal. The adapted probes were placed deeper and closer to temporal lobe of the brain to bypass confining skull bone and improve neural recordings. METHODS: Twenty adults with tinnitus and 20 nontinnitus controls listened to periods of silence and broadband noise (BBN) during standard cap and adapted ear canal fNIRS neuroimaging. The evaluators were not blinded, but the protocol and postprocessing for the two groups were identical. RESULTS: Standard fNIRS measurements in participants with tinnitus revealed increased auditory cortex activity during silence that was suppressed during auditory stimulation with BBN. Conversely, controls displayed increased activation with noise but not during silence. Importantly, adapted ear canal fNIRs probes showed similar hemodynamic responses seen with cap probes in both tinnitus and controls. CONCLUSIONS: In this proof of concept study, we have successfully fabricated, adapted, and utilized a novel fNIRS technology that replicates established findings from traditional cap fNIRS probes. This exciting new innovation, validated by replicating previous and current cap findings in auditory cortex, may have applications to future studies to investigate brain changes not only in tinnitus but in other pathologic states that may involve the temporal lobe and surrounding brain regions. LEVEL OF EVIDENCE: NA.

Comparison of esophageal placement of Bravo capsule system under direct endoscopic guidance with conventional placement method.

BACKGROUND/AIMS: Conventional placement of a wireless esophageal pH monitoring device in the esophagus requires initial endoscopy to determine the distance to the gastroesophageal junction. Blind placement of the capsule by the Bravo delivery system is followed by repeat endoscopy to confirm placement. Alternatively, the capsule can be placed under direct vision during endoscopy. Currently there is no published data comparing the efficiency of one method over the other. The objective of this study was to compare the method of Bravo wireless pH device placement under direct visualization with the conventional method. METHODS: This retrospective study involved 58 patients (29 patients with indirect and 29 patients with direct visualization) who underwent Bravo capsule placement. The physician's endoscopy procedure notes, nurse's notes, post-procedure notes, recovery notes, and pH monitoring results were reviewed. The safety of the procedure, length of the procedure and patient tolerability were evaluated. RESULTS: None of the 58 patients had early detachment of the device or any immediate procedure-related complications. Overall incidence of complications in both groups was similar. No failures due to the technique were noted in either group. The average amount of time taken for the procedure was similar in the two groups. CONCLUSIONS: The technique of placing Bravo pH device under direct visualization is as safe and effective as the conventional method. In addition, the direct visualization technique has an added advantage of avoiding a second endoscopic intubation. The length of the procedure is similar between the two techniques.

Comparison of esophageal placement of Bravo capsule system under direct endoscopic guidance with conventional placement method.

BACKGROUND: Conventional placement of a wireless esophageal pH monitoring device in the esophagus requires initial endoscopy to determine the distance to the gastroesophageal junction. Blind placement of the capsule by the Bravo delivery system is followed by repeat endoscopy to confirm placement. Alternatively, the capsule can be placed under direct vision during endoscopy. Currently there are no published data comparing the efficiency of one method over the other. The objective of this study was to compare the method of Bravo wireless pH device placement under direct visualization with the conventional method. METHODS: A retrospective study involving 58 patients (29 patients with indirect and 29 patients with direct visualization) who had Bravo capsule placement. The physician endoscopy procedure notes, nurse's notes, postprocedure notes, recovery notes, and pH monitoring results were reviewed. The safety of the procedures, length of the procedures, and patient tolerability were evaluated. RESULTS: None of the 58 patients had early detachment of the device and had no immediate procedure-related complications. The overall incidence of complications in both the groups was similar. No failures due to the technique were noted in either group. Average amount of time taken for the procedure was similar in both groups. CONCLUSION: The technique of placing a Bravo pH device under direct visualization is as safe and effective as the conventional method. In addition, there is an added advantage of avoiding a second endoscopic intubation in the direct visualization technique.