Relationship between clinical measures of hearing and clinical measures of vestibular function

PURPOSE

Patients often have basic audiometry (BA) but not objective diagnostic tests of the vestibular system (VNG) when complaining of symptoms of a vestibular disorder. The relationship of BA results to VNG results is unknown. This study sought to determine if BA scores are related to impaired VNG scores.

MATERIALS AND METHODS

We reviewed electronic medical records at a tertiary care center, for patients seen between 2015 and 2021 who had had both a BA and a VNG (n = 651). BA subtests were pure tone averages, word recognition, and tympanogram. VNG subtests were cervical vestibular evoked myogenic potentials, Dix-Hallpike maneuvers, and bi-thermal caloric tests. All tests were summarized as normal/abnormal.

RESULTS

More subjects had abnormal BA than abnormal VNG scores. Age but not sex was significantly related to abnormal scores. High BP was a significant comorbidity in 15 % of the sample, more in patients with abnormal than normal VNG scores. Although the abnormal BA and abnormal VNG were significantly related, pure tone averages and tympanogram scores were not related to VNG subtests. Abnormal word recognition with both ears combined was significantly related to normal and abnormal bi-thermal caloric tests.

CONCLUSIONS

If the clinician needs to know of any VNG impairment, in general, then performing a BA without a VNG might suffice. If the clinician needs information about the details of possible vestibular impairment, then a VNG should be performed.

Usefulness of Exam Questions and Vital Signs for Predicting the Outcome of Objective Vestibular Tests

OBJECTIVES/HYPOTHESIS

To determine the value of standard clinic screening questions and vital signs in predicting abnormal vestibular function, indicated by standard objective diagnostic tests.

STUDY DESIGN

Retrospective records review.

METHODS

We reviewed electronic medical records of 150 patients seen by the neurotologists or the physician assistant they supervised, in an out-patient tertiary care clinic, between June 2018 and March 2020, and subsequently referred for the complete objective vestibular test battery (VB).

RESULTS

Of standard questions asked during the initial exam about vertigo, disequilibrium, lightheadedness and oscillopsia, only vertigo predicted an abnormal response on the VB. More males than females had abnormal VB responses, P < .05. Pulse was not related to VB score. Significantly more subjects with blood pressure in the range for stage 2 hypertension (blood pressure [BP] stage 2) had abnormal than normal results on the VB, P < .00001. Subjects with BP stage 2 had high rates of diabetes (34.2%) and hypertension (68.4%) as diagnosed by their primary care physicians or cardiologists.

CONCLUSION

Complaints of subjective vertigo and BP in the range of hypertension stage 2 are most likely to predict abnormal findings on the VB. Therefore, during an examination of a patient who comes in complaining of dizziness, two measures may be the most useful for screening: BP in the range of hypertension type 2, when BP is taken by a nurse, and a question to determine whether or not the patient has true vertigo.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:1382-1385, 2021.

Antibiotic microspheres: preliminary testing for potential treatment of osteomyelitis

Osteomyelitis is a difficult problem for orthopaedic surgeons. The current standard of treatment requires high doses of antibiotic to be administered parenterally, which can damage vital organs. A local drug delivery system, which targets only the infected tissues, would eliminate some of the complications associated with extended courses of parenteral antibiotic treatment. In the current study, biodegradable microspheres were manufactured from a high molecular weight copolymer of 50% lactic and 50% glycolic acid and the antibiotic tobramycin. Various formulations of microspheres were tested for in vitro elution characteristics to determine the optimum formulation for linear release of antibiotic for at least 4 weeks. The optimal formulation then was implanted into a pouch created in the quadriceps muscle of mice to evaluate the in vivo elution of the antibiotic and the inflammatory response elicited by the microspheres. Results indicate that a sustained linear release of antibiotic from the microspheres is possible for a period of at least 4 weeks and that the inflammatory response was within levels required for the microspheres to be considered biocompatible.

Genes and regulatory sites of the "host-takeover module" in the terminal redundancy of Bacillus subtilis bacteriophage SPO1

Early in infection of Bacillus subtilis by bacteriophage SPO1, the synthesis of most host-specific macromolecules is replaced by the corresponding phage-specific biosyntheses. It is believed that this subversion of the host biosynthetic machinery is accomplished primarily by a cluster of early genes in the SPO1 terminal redundancy. Here we analyze the nucleotide sequence of this 11.5-kb "host-takeover module," which appears to be designed for particularly efficient expression. Promoters, ribosome-binding sites, and codon usage statistics all show characteristics known to be associated with efficient function in B. subtilis. The promoters and ribosome-binding sites have additional conserved features which are not characteristic of their host counterparts and which may be important for competition with host genes for the cellular biosynthetic machinery. The module includes 24 genes, tightly packed into 12 operons driven by the previously identified early promoters PE1 to PE12. The genes are smaller than average, with half of them having fewer than 100 codons. Most of their inferred products show little similarity to known proteins, although zinc finger, trans-membrane, and RNA polymerase-binding domains were identified. Transcription-termination and RNase III cleavage sites were found at appropriate locations.