Differentiation between cerebrospinal fluid and serum with electronic nose.

OBJECTIVE: The study investigates the ability of the electronic nose to differentiate between cerebrospinal fluid (CSF) and serum and to identify an unknown specimen as CSF or serum. STUDY DESIGN AND SETTING: CSF and serum specimens were heated and tested with an organic semiconductor-based Cyranose 320 electronic nose (Cyrons Sciences, Pasadena, CA). Data from the 32-element sensor array were subjected to principal component analysis to depict differences in odorant patterns. RESULTS: The electronic nose was able to distinguish between CSF and serum isolates with Mahalanobis distance >5. Furthermore, the electronic nose was able to place unknown specimens in the appropriate class of CSF or serum. CONCLUSIONS: The electronic nose is a novel method that may allow rapid, low cost, and reliable distinction between CSF and serum in a clinical setting. SIGNIFICANCE: Because the results are available almost immediately, the electronic nose is a powerful tool that in the future may allow for rapid diagnosis of CSF leaks in the office setting.

Diagnosis of middle ear disease using tympanograms and digital imaging.

OBJECTIVE: The study investigates the ability of physicians with different levels of training to accurately identify middle ear (ME) pathology using tympanograms and tympanic membrane (TM) digital photographs. STUDY DESIGN AND SETTING: Groups of medical students, internal medicine residents, and attending and resident otolaryngologists were presented with a set of 50 matched tympanograms and photographs of TMs. The physicians were asked to differentiate between a normal and an abnormal-appearing TM. The sensitivity and specificity of diagnosis of ME pathology by physicians were compared with the gold standard, examining the ME cavity for pathology during myringotomy. RESULTS: The sensitivity did not vary among physicians with different levels of training; however, specificity improved with an increase in physician experience. CONCLUSIONS AND SIGNIFICANCE: This study establishes a baseline for accuracy of diagnosis of ME pathology using tympanograms and photographs of TMs as compared with binocular otomicroscopy and the gold standard, myringotomy. EBM RATING: B-2.

The efficacy of corticosteroids in restoring hearing in patients undergoing conservative management of acoustic neuromas.

OBJECTIVE: To evaluate the role of corticosteroids in restoring hearing in patients undergoing conservative management of acoustic neuromas. STUDY DESIGN: Prospective cohort. SETTING: Tertiary referral center. PATIENTS: Seven patients with acute hearing loss secondary to an acoustic neuroma. INTERVENTION: Oral prednisone (1 mg/kg for 1 to 2 weeks) within a week of onset of hearing loss. MAIN OUTCOME MEASURES: Audiometric assessment at the time of presentation and after corticosteroid therapy. RESULTS: All seven patients had pure tone reception threshold improvements ranging from 10 to 50 dB in at least two frequencies or more. Speech discrimination thresholds improved after therapy in all seven patients, with gains of 4 to 38% points. CONCLUSIONS: Patients with acoustic neuromas who are being treated with a "watchful waiting" approach should receive corticosteroid treatment at the first signs of hearing deterioration. An evaluation to rule out a retrocochlear lesion is mandated in patients with sudden hearing loss, regardless of whether the hearing loss responds to corticosteroid treatment. Older data documenting the efficacy of corticosteroids in the treatment of sudden hearing loss may need to be reevaluated, given that many of these studies were conducted before MRI was available.