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Biomedical subjects

T Ricketts

Publications and source records attributed to T Ricketts.

At least 19 recordsLinked to original sources
PubMed2001

Impact of compression and hearing aid style on directional hearing aid benefit and performance.

OBJECTIVE: To evaluate the impact of low-threshold compression and hearing aid style (in-the-ear [ITE] versus behind-the-ear [BTE]) on the directional benefit and performance of commercially available directional hearing aids. DESIGN: Forty-seven adult listeners with mild-to-moderate sensorineural hearing loss were fit bilaterally with one BTE and four different ITE hearing aids. Speech recognition performance was measured through the Connected Speech Test (CST) and Hearing in Noise Test (HINT) for a simulated noisy restaurant environment. RESULTS: For both the HINT and CST, speech recognition performance was significantly greater for subjects fit with directional in comparison with omnidirectional microphone hearing aids. Performance was significantly poorer for the BTE instrument in comparison with the ITE hearing aids when using omnidirectional microphones. No differences were found for directional benefit between compression and linear fitting schemes. CONCLUSIONS: No systematic relationship was found between the relative directional benefit and hearing aid style; however, the speech recognition performance of the subjects was somewhat predictable based on Directivity Index measures of the individual hearing aid models. The fact that compression did not interact significantly with microphone type agrees well with previously reported electroacoustic data.

Acoustic Stimulation↗
PubMed2000

Directivity quantification in hearing aids: fitting and measurement effects.

OBJECTIVE: To evaluate the impact of venting, microphone port orientation, and compression on the electroacoustically measured directivity of directional and omnidirectional behind-the-ear hearing aids. In addition, the average directivity provided across three brands of directional and omnidirectional behind-the-ear hearing aids was compared with that provided by the open ear. DESIGN: Three groups of hearing aids (four instruments in each group) representing three commercial models (a total of 12) were selected for electroacoustic evaluation of directivity. Polar directivity patterns were measured and directivity index was calculated across four different venting configurations, and for five different microphone port angles. All measurements were made for instruments in directional and omnidirectional modes. Single source traditional, and two-source modified front-to-back ratios were also measured with the hearing aids in linear and compression modes. RESULTS: The directivity provided by the open (Knowles Electronics Manikin for Acoustic Research) ear was superior to that of the omnidirectional hearing aids in this study. Although the directivity measured for directional hearing aids was significantly better than that of omnidirectional models, significant variability was measured both within and across the tested models both on average and at specific test frequencies. Both venting and microphone port orientation affected the measured directivity. Although compression reduced the magnitude of traditionally measured front-to-back ratios, no difference from linear amplification was noted using a modified methodology. CONCLUSIONS: The variation in the measured directivity both within and across the directional microphone hearing aid brands suggests that manufacturer's specification of directivity may not provide an accurate index of the actual performance of all individual instruments. The significant impact of venting and microphone port orientation on directivity indicate that these variables must be addressed when fitting directional hearing aids on hearing-impaired listeners. Modified front-to-back ratio results suggest that compression does not affect the directivity of hearing aids, if it is assumed that the signal of interest from one azimuth, and the competing signal from a different azimuth, occur at the same time.

Equipment Design↗
PubMed2000

Impact of noise source configuration on directional hearing aid benefit and performance.

OBJECTIVE: To evaluate the impact of the position of noise source(s) and reverberation on the directional benefit and performance of three commercially available directional hearing aids. DESIGN: Directional benefit and performance were measured for four different configurations of competing noise source(s) in two different reverberant rooms. Three pairs of hearing aids representing three commercial models were selected based on electroacoustic evaluation of directivity. Directional benefit and performance of 25 subjects with symmetrical, sloping, sensorineural hearing loss were measured in all test environments using a modified version of the Hearing in Noise Test. RESULTS: Both reverberation and configuration of the competing noise source(s) significantly affected directional benefit and performance. There was no significant correlation between directional benefit and directional performance. The order of benefit and performance across hearing aid brands (from best to worst) varied depending on the noise source configuration. CONCLUSIONS: Data revealed increasing reverberation significantly decreased directional benefit and performance. The absolute and relative (rank ordering) directional benefit and performance varied across hearing aid brand, with noise source configuration. These results suggest that data collected in traditional test environments (e.g., a single competing noise placed at 180 degrees azimuth) cannot be used to accurately predict directional benefit or performance in the majority of other test and real-world environments. The impact of reverberation and noise source configuration on directional benefit/performance can be explained fairly well by the interaction between the spatial properties of the noise source(s) and the polar directivity patterns of the hearing aids.

Aged↗
PubMed2000

The impact of head angle on monaural and binaural performance with directional and omnidirectional hearing aids.

OBJECTIVE: To evaluate the impact of head turn and monaural and binaural fittings on the sentence reception thresholds of hearing-impaired listeners wearing directional and omnidirectional hearing aids. DESIGN: Sentence reception thresholds were measured for 20 listeners fit monaurally and binaurally with behind-the-ear hearing aids set in both directional and omnidirectional modes. All listeners exhibited symmetrical, sloping, sensorineural hearing loss. The aided performance across these four fittings was evaluated for three different head and body angles. The three angles reflected body turns of 0 degrees, 15 degrees, and 30 degrees as measured relative to the primary sound source, with 0 degrees denoting the listener directly facing the sound source. Listeners were instructed to keep their heads in a fixed horizontal position and turn their heads and bodies to face visual targets at the three test angles. Sentences from the Hearing in Noise Test presented with a background of five, spatially separated, uncorrelated samples of cafeteria noise served as test material. All testing was performed in a moderately reverberant (Rt = 631 msec) "living room" environment. RESULTS: Participants generally performed significantly better when fit with directional versus omnidirectional hearing aids, and when fit binaurally versus monaurally across test conditions. The measured "binaural advantage" was reduced with increasing head angle. Participants performed significantly better with a 30 degree head angle than when directly facing the primary speaker. This "head turn advantage" was most prominent for monaural (versus binaural) conditions. Binaural and head turn advantages were not significantly different across directional and omnidirectional modes. CONCLUSIONS: These data provide additional support for the use of directional hearing aids and binaural amplification to improve speech intelligibility in noisy environments. The magnitude of these advantages was similar to that reported in previous investigations. The data also showed that hearing aid wearers achieved significantly better speech intelligibility in noise by turning their heads and bodies to a position in which they were not directly facing the sound source. This head turn advantage was in good agreement with the increase in Directivity Index with head turn and reflected the fact that hearing aids are generally most sensitive to sounds arriving from angles other than directly in front of the hearing aid wearer. Although these data suggest that many monaural hearing aid wearers may significantly improve speech intelligibility in noise through the use of head turn, the interaction between this advantage and the potential loss of visual cues with head turn is unknown.

Adult↗
PubMed1999

Making sense of directional microphone hearing aids.

We have witnessed a large increase in the availability of directional microphone hearing aids over the past few years. Directional microphone technology is now available in analog, digitally controlled analog, and digital hearing aids, and has been implemented into both behind-the-ear and in-the-ear styles. This Short Course reviews basic design differences across directional microphone hearing aids. A number of different laboratory and clinical evaluation methods used for assessment of both electroacoustic and behavioral directivity are then reviewed. In addition, the potential impact of test conditions such as room reverberation and type and position of competing noise(s), on listener performance when fit with directional hearing aids are considered. Recommendations and suggestions relating to the clinical and laboratory assessment of directional hearing aids are provided.

Acoustic Stimulation↗
PubMed1999

Colon cancer treatment in rural North and South Carolina.

The purpose of this study was to determine the degree to which colon cancer treatment in rural North and South Carolina in 1991 and 1996 conformed to national treatment recommendations. Data came from medical records of colon cancer patients residing in rural North and South Carolina. The National Cancer Institute's Physician Data Query (PDQ) database was used to define state-of-the-art care and to categorize receipt of primary and/or adjuvant treatment. Changes in treatment over time, location, and stage and bivariate relationships between treatment and selected covariates were assessed with chi-square and Fisher's exact tests. Regression was used to control for possible interactions between patient and/or disease characteristics and treatment. The majority of colon cancer cases received primary therapy as suggested by the PDQ which was not significantly related to other factors examined. There was variation in provision of adjuvant therapy. Stage III patients received adjuvant therapy significantly more often than did stage II patients (p </= 0.01). Receipt of appropriate adjuvant therapy among stage III patients was significantly associated with younger patient age and white race (p </= 0.05). Rural colon cancer patients are likely to receive primary therapy as recommended by the PDQ, but may be less likely to receive suggested adjuvant therapy. Further understanding of variations in the rate of adjuvant therapy for colon cancer is needed to ensure appropriate treatment regimens are obtained for rural colon cancer patients.

Adult↗
PubMed1999

Competitive behavior in local physician markets.

Competition often is viewed as a mechanism for controlling cost. Competition may work well in urban areas with many providers; competition may not exist in rural areas with few providers. The authors use the empirical framework developed by Bresnahan and Reiss to analyze the entry behavior of physicians into local markets to determine the level of physician supply consistent with competitive behavior. The study estimates entry patterns for total and specialty physicians located in nonmetropolitan health service areas using longitudinal data. The authors find a surprising drop in the population increments necessary for entry by the second provider, possibly due to the unattractiveness of being the solo physician in an area. Subsequent population increments stabilize at three to five physicians. Since more than 93 percent of the U.S. population lives in areas that can support three to five physicians, competition between physicians through mechanisms such as managed care may be feasible.

Catchment Area, Health↗
PubMed1999

Comparison of performance across three directional hearing aids.

This study compared the speech recognition performance of 12 hearing-impaired listeners fit with three commercially available behind-the-ear hearing aids in both directional and omnidirectional modes. One digitally programmable analog and two "true digital" hearing aids were selected as test instruments. Testing was completed in both "living room" and anechoic room environments. Speech recognition was examined using modified forms of the Hearing in Noise Test and the Nonsense Syllable Test. The single competing stimuli of these tests were replaced with five uncorrelated competing sources. Results revealed a significant speech recognition in noise advantage for all directional hearing aids in comparison to their omnidirectional counterparts. Maximum performance of the directional hearing aids did not significantly vary across circuit type, suggesting that processing differences did not affect maximum directional hearing aid performance. In addition, the results suggest that performance in one reverberant environment cannot be used to accurately predict performance in an environment with differing reverberation.

Acoustic Stimulation↗
PubMed1997

The therapeutic effects of tenidap in canine experimental osteoarthritis: relationship with biochemical markers.

OBJECTIVE: To define the dose-response relationship of the therapeutic effects of tenidap in experimental osteoarthritis (OA) and relate this to the effects on interleukin 1 (IL-1) and metalloprotease activity. METHODS: The anterior cruciate ligament of the right knee joints of 22 mongrel dogs were sectioned (ACLS) through a stab wound. Seven dogs received no treatment, 5 were treated with oral omeprazole (20 mg/day), another 5 were treated with oral tenidap (1.5 mg/kg bid) plus omeprazole (20 mg/day), and 5 received tenidap (0.5 mg/kg bid) plus omeprazole (20 mg/day). The dogs received medication for 8 weeks beginning 4 weeks after surgery. All dogs were killed 12 weeks after surgery, except for those in the first group, which were sacrificed at 4 weeks. Lesions were evaluated macroscopically for the incidence and size of osteophytes and the area and grade of cartilage erosions on the condyles and plateaus, along with histologic evaluation of the severity of the cartilage lesions and synovial inflammation. Stromelysin, collagenase, and gelatinase activities were measured in cartilage and synovial membrane. Also, the level of IL-1 activity was measured in the synovial fluid. RESULTS: Dogs treated with tenidap at both 1.5 and 0.5 mg/kg bid exhibited a reduction in the size of osteophytes (2.25 +/- 0.30 mm, 1.70 +/- 0.65 mm, respectively) compared to the 12 weeks OA group (3.55 +/- 0.94 mm). Tenidap also significantly decreased the size and/or grade or cartilage macroscopic lesions on both condyles and plateaus. This reduction was more pronounced in dogs treated with the higher drug dose. The histological severity of cartilage lesions on femoral condyles was reduced for both tenidap doses used and significance (p < 0.04) reached for the 1.5 mg/kg bid tenidap treated dogs. Tenidap markedly and significantly reduced the level of metalloprotease activity for all 3 enzymes tested in synovial membrane (stromelysin, p < 0.03; collagenase, p < 0.02; gelatinase, p < 0.03) and in cartilage (stromelysin, p < 0.02; collagenase, p < 0.02; gelatinase, p < 0.03) with greater reduction, in general, in dogs treated with the higher dose of tenidap. IL-1 activity was significantly reduced (p < 0.02) only in animals treated with tenidap at 1.5 mg/kg bid. CONCLUSION: This study confirms that tenidap is an effective anti-osteoarthritic drug in this ACLS model where therapy was begun 4 weeks after surgery. We have defined doses that gave graded therapeutic effects, and under these conditions the effectiveness coincided with the suppression of IL-1 and metalloprotease activity, processes known to play a major role in the pathophysiology of OA lesions.

Animals↗
PubMed1996

General satisfaction and satisfaction with nursing communication on an adult psychiatric ward.

A client satisfaction survey was undertaken on an adult psychiatric admission ward in Sheffield, England, being sent to all clients discharged from the ward over 12 months. The questionnaire consisted of a general satisfaction element, and two questions asking about satisfaction with nursing communication. The response rate was 81 from 199 forms sent. General satisfaction levels were lower than for a sample of 3120 mainly out-patient psychiatric clients in the USA. Satisfaction with nursing communication was significantly correlated with general satisfaction. The survey allowed the number of dissatisfied clients to be identified, and their views highlighted. One aspect often reported by dissatisfied clients was a perceived lack of time from staff. The importance of nursing communication with respect to client satisfaction is highlighted by the study.

Adolescent↗
PubMed1994

Helpfulness of mental health day care: client and staff views.

Seventeen clients of a mental health day service were interviewed regarding their treatment experiences. Content analysis of this information was undertaken, and the clients then rank-ordered the reported aspects of treatment from most to least helpful. Staff undertook a similar procedure to enable clients' views to be placed in context. Both clients and staff reported counselling as the most helpful aspect of treatment. Clients and staff disagreed as to the relative helpfulness of medical and group aspects of treatment. Clients reported medical treatment as the second most helpful aspect, and staff reported groups and the planned approach to care second. Social contact with other clients was reported to be just as helpful as organized group therapy by clients. Clients identified that just having somewhere to go to meet people was very helpful. Communication difficulties between staff and clients were evident with regard to the planned approach to care, discharge planning, and group activities. The ability of clients to evaluate their treatment experiences differentially is highlighted.

Adult↗
PubMed1992

Multivariate population-based analysis of the association of county trauma centers with per capita county trauma death rates.

UNLABELLED: The purpose of this study was to utilize a large population-based data base to determine the association of trauma centers with per capita county trauma death rates. METHODS: Per capita county trauma death rate, the dependent variable in the model, was obtained from a well-validated state Medical Examiner's data base. Over 200 county demographic, prehospital, and hospital trauma care resource variables were obtained from a variety of sources for multivariate modeling. Bivariate analysis identified candidate variables for multivariate modeling, excluding highly correlated independent variables to avoid problems of collinearity. Multivariate linear regression, logistic regression, and stepwise discriminant analysis were used to determine the relative association of the candidate variables with per capita county trauma death rates. RESULTS: Bivariate analysis identified multiple factors associated with per capita county trauma death rates. These included, among others: county rurality, percentage of unemployment, percentage nonwhite, 911 access, and ALS certified EMS. Per capita trauma death rates were significantly lower in counties with trauma centers compared with counties without trauma centers (4.0 +/- 0.5 and 5.0 +/- 1.1 deaths per 10,000 population, p = 0.0001, respectively). Multivariate analysis demonstrated that the presence of a trauma center in the county and ALS were the best medical system factors predicting decreased per capita county trauma death rates. CONCLUSIONS: This study is unique in utilizing a regional population-based data base of all trauma deaths in a large state to analyze the association of trauma centers and trauma death rates. Multivariate modeling controlling for other county variables demonstrated that the presence of a trauma center and Advanced Life Support training were the best predictors of per capita county trauma death rates. These findings are consistent with the hypothesis that trauma centers decrease trauma death rates.

Adult↗
PubMed1989

Evaluating organizational design to assure technology transfer: the case of the Community Clinical Oncology Program.

Current theories of organizational performance are used to guide researchers at the Health Services Research Center of the University of North Carolina at Chapel Hill and the University of Illinois Survey Research Laboratory in the evaluation of the National Cancer Institute's Community Clinical Oncology Program (CCOP) and to derive policy options to enhance program operations. CCOP represents an innovative mechanism designed to improve the accrual of patients to phase III clinical trials, involve community-based oncologists in clinical research, and potentially to disseminate new information on the state-of-the-art cancer treatment to areas distant from cancer centers and research-oriented medical centers. Examined in this evaluation of the second phase of the CCOP are the ability of the 52 currently funded CCOPs and 17 research bases to accrue patients to cancer treatment and cancer control research protocols, their influence on the patterns of practice for cancer treatment in CCOP communities, and their influence on cancer control awareness and activity among primary care physicians. The evaluation applies selected organizational perspectives to describe the intraorganizational and interorganizational characteristics of the CCOPs, research bases, and the Institute that may affect the performance of the CCOP. This organizational approach relates the accrual and influence of the CCOP to controllable aspects of the program's design and management strategies that can be changed through policies directed by the National Cancer Institute. These policies include the criteria used to select CCOPs, the role of research bases in the development and implementation of treatment and cancer control research protocols, and the use of accrual credits.

Academies and Institutes↗
PubMedDate not supplied

Consumer satisfaction surveys in mental health.

Treating clients of mental health services as consumers is a relatively new concept in Britain. This article seeks to explain the development of consumer satisfaction surveys, reviews the literature, and identifies ways in which the approach can be used to improve services.

Consumer Behavior↗
PubMedDate not supplied

Therapist self-disclosure in behavioural psychotherapy.

Therapist self-disclosure has been poorly defined until recently. This article presents a model of verbal self-disclosure and relates it to both client-centred therapy and counselling as social influence. The implications for behavioural psychotherapy are then reviewed.

Behavior Therapy↗
PubMedDate not supplied

Grief: a cognitive-behavioural perspective.

Models of grief utilised by nurses remain largely descriptive. This article considers a cognitive-behavioural model of grief and applies it to the problems of morbid grief. Two case studies illustrate how the model may be used to guide interventions.

Adaptation, Psychological↗