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Biomedical subjects

B W Blakley

Publications and source records attributed to B W Blakley.

At least 19 recordsLinked to original sources
PubMed2001

The meaning of the word "vertigo".

OBJECTIVE: To determine whether otologists see a need to further define the word "vertigo" and assess the variety of meanings that are meant in using the word. METHODS: A questionnaire was mailed to 720 members of the American Otological Society (AOS) and American Neurotological Society (ANS) to assess the need for further definition and the current understanding of the meaning of "vertigo." RESULTS: The response rate was 42%. Significant variability in the intended meaning of the word "vertigo" was found suggesting that the definition is inconsistent among experts. Three quarters of the respondents indicated that the word needs further definition. The word was most commonly used to indicate sensations that include spinning or turning only. CONCLUSION: The definition of the term "vertigo" is inconsistent among otolaryngologists. Refinement of the definition is desirable for accurate history taking and should be limited to false illusions of circular motion.

Humans↗
PubMed2001

Local vestibular blood flow and systemic vascular responses to natural vestibular stimulation in the Mongolian gerbil.

HYPOTHESIS: Natural stimulation of the vestibular end organs will produce alterations in the local vestibular microvascular blood flow. BACKGROUND: The vestibular and cardiovascular systems require a coordinated interaction to maintain organ perfusion during rapid positional and postural changes. However, the detailed relationship of these systems is not well understood. There have been no previous descriptions of local vestibular blood flow (VBF) during natural stimulation (NS) conditions. METHODS: In vivo VBF and systemic blood pressure (BP) in the Mongolian gerbil during natural stimulation. Using laser Doppler flowmetry, the authors obtained continuous measures of local VBF in both anesthetized and alert gerbils during sinusoidal rotational stimuli. Simultaneous recordings of systemic BP were collected from the contralateral common carotid artery. RESULTS: The anesthetized gerbils showed stable VBF and BP during all vestibular stimuli. By contrast, alert subjects demonstrated a significant response to natural stimulation. The VBF increased 28% over baseline, and systemic BP increased 8% during a 45-second, 0.133-Hz sinusoid. Decreases in BP of 8% and 5%, respectively, were seen with a 0.10 and 0.20 Hz, 360-second stimulus. A corresponding determination of VBF during the extended stimulus conditions was not technically possible. CONCLUSIONS: To the authors' knowledge, these are the first in vivo descriptions of vestibular blood flow during natural stimulation. In the alert animals, VBF increased in response to NS. This increase in flow does not appear to be directly dependent on systemic blood pressure changes and indicates that the vestibular microvasculature is closely regulated.

Animals↗
PubMed2000

Update on intratympanic gentamicin for Meniere's disease.

OBJECTIVE: To review the literature relating to intratympanic gentamicin injection therapy for Meniere's disease to detect consistencies and differences that might suggest optimal technique. DESIGN: Retrospective literature review. METHODS: Eighteen papers from the literature regarding clinical experience with intratympanic gentamicin injections for treatment of Meniere's disease were reviewed and tabulated. RESULTS: All papers reported high success rates in treating episodic vertigo of Meniere's disease, but technique, dose, duration, and treatment philosophy varied considerably. Hearing loss was typically reported in about 30% of patients. CONCLUSION: No single technique of gentamicin injection has a significant medical advantage over the others. Until controlled studies indicate otherwise, nonmedical needs such as convenience and safety may be considered when choosing a technique.

Gentamicins↗
PubMed1999

Vestibular rehabilitation on a budget.

OBJECTIVE: This study was conducted to compare the results of an office-based vestibular rehabilitation program with the results from other larger programs in the literature. METHOD: Using a retrospective chart review, 138 dizzy patients seen in a tertiary medical centre were asked to perform directed exercises. Significant subjective improvement reported by the patients. RESULTS: Sixty-six percent of patients improved with this form of vestibular rehabilitation after 1 month. The results compare favourably with improvement rates from other centres in the literature with large, multidisciplinary teams. CONCLUSION: Vestibular rehabilitation therapy can be effectively administered from an office-based program.

Ambulatory Care↗
PubMed1999

Antidepressants and dizziness.

OBJECTIVE: To assess the clinical therapeutic significance of sleep disruption and admitted depression in patients with nonspecific dizziness. DESIGN: Retrospective database review. SETTING: Large tertiary care clinical practice. METHOD: Answers to questions about sleep disruption and depression from 137 patients who met inclusion criteria for nonspecific dizziness and a comparison group of 39 patients were contrasted. The Pearson chi-square test was used to determine the statistical significance of the results. MAIN OUTCOME MEASURE: Six weeks after beginning antidepressant therapy, patients were asked if their symptoms improved significantly. RESULTS: Patients with nonspecific dizziness reported more sleep disruption and admitted to depression more frequently than the comparison group. Persons with sleep disruption were more likely to respond to antidepressant therapy than those without sleep disruption. CONCLUSIONS: (1) Sleep disruption is common in persons with nonspecific dizziness. (2) Nonspecific dizziness may respond to antidepressant therapy, particularly in patients who report sleep disruption and/or depression.

Adult↗
PubMed1998

Preoperative hearing predicts postoperative hearing.

Optimal hearing is one goal of otologic surgery. It is generally presumed that hearing thresholds after tympanoplasty-mastoidectomy surgery are determined by remaining anatomy. We assessed the effect of the disease process on hearing after surgery, and our data do not support this presumption. We studied the relationship between preoperative and postoperative hearing across tympanoplasties with differing anatomies in 124 patients without ossicular reconstruction with prostheses or bone. Our results indicate that poor hearing before surgery is associated with poor hearing after surgery, regardless of anatomy (type of tympanoplasty). This relationship holds for both the airbone gap and the speech-reception threshold. When considering ossicular reconstruction, the surgeon should remember that the disease process itself affects hearing in addition to the physical attributes of the ear. These results should be considered in preoperative counseling, as well as in the interpretation of the otologic literature.

Audiometry↗
PubMed1998

Does chronic otitis media cause sensorineural hearing loss?

OBJECTIVE: The purpose of this study was to determine whether chronic middle ear infection is associated with sensorineural hearing loss. METHOD: Audiometric data from 123 patients with unilateral chronic otitis media were compared using the non-involved ear as a control. The average bone threshold at 500, 1000, and 2000 Hz, the speech reception threshold, and the extent of the disease was compared using the t-test, linear regression, and MANOVA techniques. RESULTS: A highly significant association was found between the presence of chronic otitis media and sensorineural hearing loss. The great variability in our data imply that some individuals are particularly susceptible to chronic otitis media. We offer one suggestion as to why this may occur. CONCLUSION: Sensorineural hearing loss is associated with chronic ear infection with some persons being particularly vulnerable.

Adolescent↗
PubMed1997

Comparison of five agents in protecting the cochlea against the ototoxic effects of cisplatin in the hamster.

The purpose of this investigation was to study the ameliorating effects of four agents on cisplatin-induced ototoxicity. Hamsters were given a series of five cisplatin injections either alone or in combination with sodium thiosulfate (STS), diethyldihydrothiocarbamate (DDTC), and S-2(3-aminopropylamino) ethylphosphorothioic acid (WR-2721), or fosfomycin. Ototoxicity was assessed anatomically by quantifying the extent of cochlear damage with the scanning electron microscope and physiologically with measures of the auditory brain stem response. When administered alone, cisplatin induced widespread loss of outer hair cells (OHCs) along much of the cochlea in the hamster, especially in the basal and middle turns, with an average survival of only 56% of the OHC population. In contrast, inner hair cells resisted cisplatin ototoxicity in the hamster. Thus the ameliorative effects of the different test agents were assessed by counting the number of surviving OHCs in each treatment group and comparing with cisplatin-treated controls. STS provided the most effective protection against the ototoxic effects of cisplatin, yielding 91% survival of OHCs. DDTC also reduced the ototoxic effects of cisplatin, yielding 68% survival of OHCs. Cotreatment with WR-2721 and fosfomycin yielded 45% and 52% OHC survival, respectively, and thus did not provide any chemoprotection. The results closely paralleled those based on auditory brain stem response recordings in that the magnitude of threshold shift was proportional to the amount of OHC loss; also, the amount of threshold shift at each frequency was in good agreement with the pattern of hair cell loss along the cochlear spiral. Thus both histologic and physiologic results suggest that STS and DDTC hold promise for ameliorating the ototoxic effects of cisplatin chemotherapy.

Amifostine↗
PubMed1997

Hearing, language, speech, vestibular, and dentofacial disorders in fetal alcohol syndrome.

Fetal alcohol syndrome (FAS) is characterized by congenital anomalies traditionally associated with hearing disorders. The present study sought to (a) evaluate possible central hearing loss; (b) verify and extend previous observations on sensorineural and conductive hearing losses; (c) evaluate possible vestibular disorders; (d) examine the relationships between hearing, speech, language, vestibular, and dentofacial disorders in FAS patients; and (e) evaluate the influence of patient age, race, and gender on the expression of these morbidities. A biracial group of 22 FAS patients (aged 3 to 26 years) were evaluated by standard hearing, speech, language, and vestibular tests. Dentofacial and other malformations were also assessed. Of the 22 FAS patients, 17 (77%) had intermittent conductive hearing loss due to recurrent serous otitis media that persisted from early childhood into adulthood, whereas 6 (27%) had sensorineural hearing loss in addition to the conductive hearing loss. Among the 12 patients tested for central hearing function, all (100%) were significantly impaired. Among the patients tested for speech and language ability, 18 of 20 (90%) had speech pathology, 16 of 21 (76%) had expressive language deficits, and 18 of 22 (82%) had receptive language deficits. Hearing, speech, and language deficits were not influenced by age, race, or gender. On the vestibular tests, all performed within normal limits with the possible exception of one child (n = 6). High incidences of dentofacial, temporomandibular joint, ocular, cardiac, and skeletal disorders were observed. Race and gender tended to influence dental malocclusion class. Two subjects exhibited autistic tendencies. In conclusion, new and important findings included a high prevalence of sensorineural, conductive, and central hearing deficits, the persistence of otitis proneness into adulthood, the existence of temporomandibular joint disorders, and the possible influence of gender or race on dental malocclusions. Such disorders can contribute to the learning, behavioral, and emotional difficulties seen in FAS patients and warrant early, aggressive intervention.

Adolescent↗
PubMed1997

Clinical forum: a review of intratympanic therapy.

OBJECTIVE: This article provides an overview of the rational basis for the appropriate clinical use of intratympanic aminoglycosides and steroids. DATA SOURCES: The data sources were relevant English language clinical and basic science publications. STUDY SELECTION: The most recent publication available for each author or group of original, human, clinical reports about the technique were included. DATA EXTRACTION: The techniques and results for control of vertigo and hearing loss were compared. CONCLUSIONS: At least 11 articles have been published that indicate that intratympanic gentamicin treatments control vertigo well and provide acceptable rates of hearing loss. Intratympanic gentamicin should be the initial treatment of choice for unilateral disabling Meniere's disease that has failed medical therapy. The use of intratympanic steroids should remain investigational until more favorable data are available.

Anti-Bacterial Agents↗
PubMed1995

Audiometric referral criteria for industrial hearing conservation programs.

OBJECTIVES: To determine referral rates resulting from application of American Academy of Otolaryngology-Head and Neck Surgery audiometric referral criteria for occupational hearing conservation programs (HCPs) in a large industrial population and to estimate the efficacy of audiometric retesting in identifying false-positive referral flags. DESIGN: Retrospective, comparing referral rates between control and noncontrol HCPs from public domain data in the American National Standards Institute Draft American National Standard: Evaluating the Effectiveness of Hearing Conservation Programs. SETTING: Occupational HCPs from the United States and Canada. PATIENTS: A total of 45,055 baseline and 27,047 second chronologic audiograms were analyzed. A subset of 3958 employees who had baseline and seven subsequent tests were examined to confirm results. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Percent of employees meeting referral criteria was calculated for unconfirmed (ie, single test) and confirmed (two consecutive tests) audiometric findings. No a priori hypotheses were formulated for referral rates for control or noncontrol HCPs. RESULTS: Noncontrol HCP referral rates were typically two to three times that of control HCPs. Control and noncontrol HCPs had about half as many audiometric referral flags when retests were used to confirm initial results. CONCLUSIONS: Mature industrial populations are likely to yield higher baseline referral rates than younger populations. Retesting may identify up to 50% of audiometric referral flags as false-positive and significantly reduce costly overreferrals. Annual referral rates of 1% to 2% seem to be achievable in well-run HCPs in which retesting is performed to identify false-positive audiometric outcomes.

Audiology↗
PubMed1995

The comparative effects of sodium thiosulfate, diethyldithiocarbamate, fosfomycin and WR-2721 on ameliorating cisplatin-induced ototoxicity.

The efficacies of four agents in ameliorating cisplatin-induced ototoxicity were investigated. Hamsters were given a series of 5 cisplatin injections (3 mg/kg/injection once every other day, i.p.) either alone or in combination with 1600 mg/kg/injection sodium thiosulfate (STS), 300 mg/kg/injection diethyldithiocarbamate (DDTC), 18 mg/kg/injection WR-2721, or 300 mg/kg/injection fosfomycin (n = 10/group). Ototoxicity was assessed electrophysiologically by auditory brainstem responses (ABRs) and anatomically by cochlear histology. The greatest auditory protection was given by STS, followed by DDTC. WR-2721 and fosfomycin did not provide any protection. All of the animals in the STS and DDTC groups survived, while some fatalities occurred in the fosfomycin, WR-2721, and cisplatin-only groups. Thus, the agents that were protective against ototoxicity were also protective against mortality. The ABRs also provided evidence of cisplatin-induced neuropathy. In summary, STS and DDTC hold promise for ameliorating the ototoxic effects of cisplatin chemotherapy and the hamster proved to be an excellent model of cisplatin ototoxicity.

Amifostine↗
PubMed1995

Smoking and middle ear disease: are they related? A review article.

The relationship between passive smoking and middle ear disease was reviewed. The hypothesis that acute otitis media, serous otitis media, and related diseases in children are caused by inhalation of second-hand smoke has been accepted by many. We reviewed the literature on this topic. There are many studies that do not support the hypothesis. There is no indication that the smokers themselves have a higher incidence of middle ear disease. Considering the difficulty of publishing negative studies, the need for academics to publish significant findings, and the poor foundation for some authors' conclusions in the literature, we find that the literature does not offer sufficient support for the hypothesis that second-hand smoke causes middle ear disease to accept the hypothesis.

Acute Disease↗