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Biomedical subjects

J M Fredrickson

Publications and source records attributed to J M Fredrickson.

At least 19 recordsLinked to original sources
PubMed2001

The Otologics MET ossicular stimulator.

The advent of various technologies for middle ear implants (MEI) that directly stimulate the ossicles has created a new therapy for hearing loss and a new segment of the medical device industry. Benefits can be established when the MEI is compared with the best alternative currently available. Otologics, LLC, has developed an electromechanical MEI (middle ear transducer (MET) Ossicular Stimulator) designed to aid individuals with moderately severe to severe sensorineural hearing loss. The efficacy of the device is determined through a clinical comparison of the MET Ossicular Stimulator to that of a state-of-the-art digital hearing aid.

Animals↗
PubMed1999

Symptoms as an index of biologic behavior in head and neck cancer.

The TNM staging system for head and neck cancer is based on the morphologic description of the tumor and disregards the clinical condition of the patient. Cancer symptoms were evaluated as a biologic index of disease to improve survival estimates. The medical records of 1010 patients receiving initial cancer treatment between 1980 and 1991 were retrospectively reviewed. The mean survival duration was 62 months for the entire population. By use of SAS statistical software (SAS Institute, Cary, NC), 48 symptom variables were screened by univariate analysis, and 23 of these variables were selected for entry into a Cox proportional hazards model on the basis of survival duration. Dysphagia, otalgia, neck lump, and weight loss were identified as independent predictors of survival duration (P < 0.01). A composite symptom-severity staging system was created on the basis of the 4 symptoms. Mean survival duration (95% CI) by symptom-severity stage was as follows: none, 74 months (70 to 79 months); mild, 56 months (51 to 61 months); moderate, 40 months (33 to 47 months); and severe, 31 months (22 to 41 months) (chi 2 = 30.8, P = 0.0001). Survival duration by TNM stage was as follows: I, 89 months (82 to 95 months); II, 71 months (65 to 78 months); III, 53 months (47 to 59 months); and IV, 42 months (37 to 47 months) (chi 2 = 56.2, P = 0.0001). When symptom-severity stage was entered in a proportional-hazards model along with TNM stage, comorbidity, age, and alcohol use, all 5 variables were independently predictive of survival duration (risk ratio: symptom severity 1.28, TNM 1.33, comorbidity 1.80, age 1.47, alcohol use 1.09). Appropriately defined symptom variables contain important prognostic information, which is independent of the TNM system. Therefore symptoms provide an index of biologic behavior in head and neck cancer.

Adolescent↗
PubMed1999

Clinical-severity staging system for oral cavity cancer: five-year survival rates.

The objective of this research is to improve the classification and survival estimates for patients with oral cavity cancer by combining cancer symptom severity and comorbidity with the current TNM staging system. The study design is a retrospective medical record review that uses explicit coding criteria. The medical records of 277 patients receiving initial treatment at the Washington University Medical Center between 1980 and 1989 were reviewed. Multivariate analysis identified patient factors that significantly affected 5-year survival. These patient factors, symptom severity and comorbidity, were combined with TNM to create a composite clinical-severity staging system. The overall 5-year survival rate was 46% (128/277). Survival rates by TNM stage were as follows: stage I, 72% (36/50); II, 54% (45/84); III, 37% (24/65); and IV, 29% (23/78) (chi2 = 25.27, P = 0.001). When patients were grouped according to the clinical-severity staging system, survival rates were as follows: stage I, 77% (33/43); II, 56% (45/80); III, 42% (43/103); and IV, 14% (7/51) (chi2 = 40.62, P = 0.001). Survival estimates can be improved by adding carefully studied and suitably defined patient variables to the TNM system. The current TNM staging system for oral cavity cancer is based solely on the morphologic description of the tumor and disregards the clinical condition of the patient. Patient factors, such as cancer symptom severity and comorbidity, have a significant impact on survival. Continued exclusion of patient factors leads to imprecision in prognostic estimates and hinders interpretation of clinical studies.

Aged↗
PubMed1998

Multivariate analysis of objective vocal function.

No standard and valid multidimensional index of objective voice function has been developed that integrates the information generated from the multiple objective parameters of voice function. The goals of this research were 1) to identify important objective voice parameters and 2) to create a multidimensional voice function index by combining relevant parameters. We evaluated 97 dysphonic patients and 35 normal volunteers on 14 objective voice parameters. Three multidimensional voice indices were created and evaluated: 1) nonweighted univariate index, 2) weighted odds ratio index, and 3) weighted multivariate regression index. The univariate index required all 14 parameters, while the odds ratio and logistic regression models required only 4 parameters (frequency range, airflow at lips, maximum phonation time, and subglottic pressure). The chi2 values for the 3 models were 37.8, 37.6, and 46.0, respectively. All 3 indices were able to satisfactorily classify voice function as normal or abnormal. However, the regression index performed best.

Confidence Intervals↗
PubMed1998

Assessment of two objective voice function indices.

In the care of patients with voice disorders, physicians, speech pathologists, and other health care professionals routinely make diagnoses, recommend treatment, and evaluate outcomes. Although objective and subjective measures exist, unfortunately, there is no widely accepted, valid method for classifying voice disorders and assessing outcome after voice treatment. In the present research, the relationship between two previously created multivariate objective voice function indices, the weighted odds ratio index and the multivariate logistic regression index, and subjective assessment of voice function was evaluated. Twenty-three adult patients presenting to a speech science laboratory for evaluation of voice disorders were studied in this prospective observational study together with 12 normal volunteers as controls. Vocal function was measured on 14 different parameters with a protocol that included a multichannel input for simultaneous assessment of acoustic and physiological parameters. Each patient was recorded reading the standard passage "The North Wind and the Sun," and recordings were then evaluated by the GRBAS scale. Overall, there was a statistically significant relationship between the weighted odds ratio index and multivariate logistic regression index and mean GRBAS scores. This research demonstrates that the voice function values calculated from two different multivariate objective voice function indices are significantly associated with subjective voice assessments. These multivariate objective voice indices may be appropriate for use in clinical trials and outcomes research on treatment effectiveness for voice disorders.

Adult↗
PubMed1997

Clinical-severity staging system for oropharyngeal cancer: five-year survival rates.

OBJECTIVE: To improve the classification and survival estimates for patients with oropharyngeal cancer by combining cancer symptom severity and comorbidity with the current TNM cancer staging system. DESIGN: Retrospective medical record review using explicit coding criteria. SETTING: University medical center. PATIENTS AND METHODS: Two hundred ninety-six patients receiving initial treatment from January 1, 1980, to December 31, 1989. Multivariate analysis identified patient factors that had a significant impact on 5-year survival. These patient factors, symptom severity and comorbidity, were combined with cancer stage to create a composite clinical-severity staging system. MAIN OUTCOME MEASURE: Five-year survival. RESULTS: The overall 5-year survival rate was 38% (111/ 296). Survival by TNM cancer stage was 67% (18/27) for stage I, 46% (24/52) for stage II, 31% (26/85) for stage III, and 32% (43/132) for stage IV (chi2=10.84; P=.001). When patients were grouped according to the clinical-severity staging system, survival rates were 70% (16 of 23) for stage A, 47% (71 of 152) for stage B, 27% (18 of 67) for stage C, and 11% (6 of 54) for stage D (chi2=34.49; P=.001). CONCLUSIONS: Survival estimates can be improved by adding carefully studied and suitably defined patient variables to the TNM cancer stage. The current TNM cancer staging system for oropharyngeal cancer is based solely on the morphologic description of the tumor and disregards the clinical condition of the patient. Cancer symptom severity and comorbidity have a significant impact on survival. Continued exclusion of patient factors leads to imprecision in prognostic estimates and hinders interpretation of clinical studies.

Disease-Free Survival↗
PubMed1995

Distortion product otoacoustic emissions in rhesus (Macaca mulatta) monkey ears: normative findings.

Distortion product otoacoustic emissions (DPOAEs) in rhesus monkeys were characterized and the optimal parameters for their generation were determined. Robust DPOAEs were readily measurable from the ear canals of six rhesus monkeys (n = 12 ears). The nonmonotonic behavior of the f2/f1 ratio functions in rhesus monkeys was found to be similar to other animals and humans. The optimal mean f2/f1 ratio of 1.21 and the effect of the primary frequency and level on the optimal f2/f1 ratios were also similar to human measurements. The contour of the rhesus monkey DPOAE 'audiograms' and their behavior were also comparable to human measurements with slight differences in peak frequencies. The rhesus monkey DPOAE input/output (I/O) functions were generally monotonic with a slope approaching unity with increasing frequency. Therefore, our study shows that many basic DPOAE characteristics are remarkably similar in the two species and emphasizes the appropriateness of the rhesus monkey as a model for DPOAE research. Detailed studies of the behavior of DPOAEs can be carried out in a model that is phylogenetically close to human both in hearing and in the gross structure and histology of the inner ear.

Acoustic Stimulation↗
PubMed1995

Squamous cell carcinoma of the pyriform sinus: a nonrandomized comparison of therapeutic modalities and long-term results.

From January 1964 through December 1991, 408 patients with squamous cell carcinomas involving the pyriform sinus were treated at Washington University Medical Center. Their ages ranged from 29 to 83 years (mean, 62.3; median 59) and the male to female ratio was 5:1. The mean duration of symptoms prior to diagnosis was 3.9 months (range 1 to 32 months) and 89% had a smoking or ethanol history. Sixty-seven percent had T3 or T4 lesions and 87% were stage III or IV at presentation. Sixty-nine percent had neck metastases. The treatment strategy varied with respect to radiation and reconstruction. Prior to 1978, preoperative radiation (3.5 to 5000 cGy) was used. Postoperative radiation was given thereafter (600+ Gy). Since 1982, flap reconstruction (usually pectoralis major myocutaneous) has been used to close the partial laryngopharyngectomy (PLP) defect. Almost all N0 necks were treated by radiation or surgery and all N1-N3 lesions were treated by combined therapy. Pyriform tumors were subdivided into three groups: 1. one-wall lesions (n = 48), 2. medial-wall lesions which involved the aryepiglottic fold or supraglottis (N = 267), and 3. two- or three-wall lesions which extended to the pyriform apex or post-cricoid region (N = 93). Ninety-five patients had single-modality therapy and 302 had combined treatment. Two hundred seven patients had conservation surgery (PLP) and 157 had total laryngopharyngectomy alone or in combination with radiation. Thirty-three patients were treated by radiation alone. Eleven patients were excluded from the study because of distant metastases (TxNxM1) at presentation. The cumulative survival (NED) at 5, 10, 15, and 20 years was 56%, 35%, 31%, and 20%, respectively. The cumulative locoregional control rate was 71%. At 5 years (NED), the cure rates for one-wall lesions (73%) were better than for medial-wall lesions (63%) or 2- and 3-wall lesions (49%). One-wall lesions were smaller, medial-wall lesions behaved similar to supraglottic tumors, and two- or three-wall tumors behaved as hypopharyngeal tumors. The cure rates were related to T stage with T1 + T2 > T3 + T4 (28%). Neck metastases reduced the cure rate by 26% and N1 > N2-N3 by an additional 12%. Other factors contributing to therapeutic failure were distant metastases (17.7%), second primary tumors (6.2%; oropharynx and lung were most common), and intercurrent disease fatalities (9.5%). The secondary therapeutic salvage rate was 44% for surgery and 32% for radiation therapy. The therapeutic complication rate was 19% with 3.6% leading to fatality.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Vibratory segment function after free flap reconstruction of the pharyngoesophagus.

Reconstructive options following total laryngopharyngectomy include thin, pliable free tissue segments, approximating the natural thickness of the pharyngeal wall. The authors have investigated outcomes in the following clinical series, emphasizing speech and swallowing. Twelve cancer patients underwent laryngopharyngectomy with or without glossectomy. Eight jejunal, 1 radial forearm, and 3 innervated latissimus dorsi flaps were used for vibratory segment (VS) reconstruction, and all 12 patients underwent tracheoesophageal puncture (TEP). Eleven patients achieved intelligible speech, with a median intelligibility of 93%. The vibrating segments showed fluttering of the free flap tissue when studied by videopharyngography. Vocal quality was lower pitched and softer than "conventional" TEP speech. All patients achieved oral intake as their primary mode of nutrition. Free flaps are a successful option for VS reconstruction in patients undergoing laryngopharyngectomy or glossopharyngolaryngectomy, obviating the need for written or electrolarynx communication.

Aged↗
PubMed1995

Squamous cell carcinomas of the aryepiglottic fold: therapeutic results and long-term follow-up.

Three hundred fifteen patients with squamous cell carcinomas involving the aryepiglottic (A-E) folds were treated between January 1964 and December 1991. The age ranged from 39 to 87 years (mean, 62.4 years; median, 61.3 years) and the male-to-female ratio was 5:1 (54 women and 261 men). Symptom duration prior to diagnosis was 4.8 months. Eighty percent of patients had T3 and T4 lesions and 56.3% had neck metastases at presentation. Six patients (1.8%) had distant metastases and were excluded from this study. Clinically the tumors presented as either exophytic infiltrating lesions which were confined to the A-E fold (n = 57) or mucosally spreading tumors which extended to the lateral supraglottis or pyriform sinus (n = 258). Prior to 1978 preoperative radiation (3000 to 5000 cGy) was used. Higher doses of postoperative radiation (5000 to 6000+ cGy) were used thereafter. After 1982 the use of myocutaneous flaps for closure of partial laryngopharyngectomy defects was routine. Almost all N0 neck disease was treated by radiation or surgery. Combined therapy was used in N1-N3 disease. One quarter of the patients had single-modality therapy (25.7%; 81 patients) with a cumulative 5-year disease-free survival of 53%. The remainder of the patients (n = 234) had combined therapy with a cumulative 5-year survival of 67.2%. The latter group had 163 conservation surgeries and 121 total laryngectomy resections. The 5-year disease-free survival for preoperative radiation with surgery (68%) and postoperative radiation with surgery (64%) was similar. Those treated by radiation alone had a 34% 5-year disease-free survival and those treated with surgery alone had a 61% 5-year disease-free survival. The cumulative locoregional control rate was 77%. The cumulative disease-free survival at 5, 10, 15, and 20 years is 66%, 57%, 55%, and 55%, respectively. Infiltrating tumors had a better disease-free survival (by more than 10%) than spreading tumors. The 5-year survival rates were separated well by clinical stages of tumors. In patients with T1 tumors the 5-year survival was 87%; in those with T2 tumors, 80%; in those with T3 tumors, 78%; and in those with T4 tumors, 41%. The survival rate was greater in those with N0 tumors than in those with N+ tumors by 25% and greater in those with N1 tumors than in those with N2 + N3 tumors by an additional 18%. The overall complication rate was 26% and in 7.7% these were fatal.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Ongoing investigations into an implantable electromagnetic hearing aid for moderate to severe sensorineural hearing loss.

Over 20 million Americans have a hearing loss that produces problems in communication. The majority of these hearing-impaired individuals would benefit from conventional hearing aids, yet only about 15% use amplification devices. Many of the reasons for the lack of use of conventional hearing aids can be resolved by an implantable middle ear device directly coupled to the ossicular chain. This article presents the advantages of the implantable middle ear device.

Acoustic Stimulation↗
PubMed1995

Use of distortion product otoacoustic emissions to assess middle ear transducers in rhesus monkeys.

Distortion product otoacoustic emissions (DPOAEs) can provide an objective and noninvasive assessment of the peripheral cochlear function. Auditory brainstem responses measured from implanted rhesus monkeys have shown that middle ear transducers, coupled directly to the incus, are capable of delivering the signals to the central auditory system. The DPOAEs were used as a noninvasive method of assessing the frequency specificity of this mechanical transduction. In two rhesus monkeys implanted with the middle ear transducers, one primary stimulating tone (f1) was presented acoustically, and the other primary tone (f2) was presented by the transducer, which converted the signal into a mechanical motion of the probe tip attached to the body of the incus. The nonlinear characteristics of the cochlea produced the distortion product responses at the expected frequencies (2f1 - f2). This demonstrates the fidelity of the middle ear implant signal transduction in vivo. The DPOAEs also indicate minimal changes in the post-implant middle ear transmission. This study demonstrates that the DPOAEs can be used to assess the function of implanted middle ear transducers objectively and noninvasively.

Animals↗
PubMed1994

Fibular and iliac crest osteomuscular free flap reconstruction of the oral cavity.

A method for reconstruction of oral cavity soft tissues using segmentally or axially supplied free muscle flaps harvested as a unit with their bone components is presented. Both fibular/soleus and iliac crest/internal oblique free flaps are documented, and the pros and cons of each donor site are presented. Twenty-one patients, 17 with cancer or osteoradionecrosis and 4 with benign or congenital conditions of the mandible, have undergone this operation. Ten bone grafts were simultaneously embedded with osseointegrated implants. All free flaps except one survived and resulted in a smoothly mucosalized oral lining. Six patients have had their implants successfully uncovered, all of whom are wearing prostheses. Four other patients are using tissue-borne prostheses. Transfer of free, nonbulky muscle flaps for mucosalized oral soft-tissue reconstruction is feasible in selected patients using first the fibular and, second, the iliac donor site; this soft-tissue technique also contributes to prosthetic dental rehabilitation.

Adolescent↗
PubMed1994

Emergency nurses' perceived knowledge and comfort levels regarding pediatric patients.

OBJECTIVE: To assess emergency nurses' levels of preparation and education regarding pediatric patients, their levels of knowledge and comfort with specific medical conditions of these patients, and the need they perceive for special policies for pediatric patients. METHODS: Surveys were mailed to nurse managers and emergency nurses in six diverse counties, including Los Angeles and vicinity. Fifty-one nurse managers and 362 emergency nurses from 51 hospitals responded to the questionnaires. RESULTS: More than half of the emergency nurses had 6 or more years of experience; many had certificates, professional designations, and pediatric nursing education. Those with more pediatric education and those designated Pediatric Advanced Life Support, Certified Emergency Nurse, and Mobile Intensive Care Nurse reported the greatest comfort and knowledge with pediatric patients. The greatest discomfort and least knowledge were associated with neonatal emergencies, major trauma, child abuse or sexual abuse, sudden infant death syndrome, envenomation, psychiatric emergencies, meningococcemia, near-drowning, respiratory arrest, and cardiac arrest. Opinions regarding the need for special pediatric policies differed in some cases from current practice. CONCLUSION: Pediatric medical conditions associated with high nurse discomfort and low knowledge point to areas of need for specific education.

Child↗
PubMed1994

Computer-stimulated test fitting of an implantable hearing aid using implantable hearing aid using three-dimensional CT scans of the temporal bone: preliminary study.

In preparation for future implantation of the implantable middle ear transducer in patients, a method was sought for preoperatively test fitting a model of the device, using computer generated three-dimensional (3-D) temporal bone images derived from spiral computed tomography (CT) data. A 3-D model of the implantable middle ear transducer was designed using NIH Image software on a Macintosh computer. High resolution human temporal bone CT scans were obtained using a spiral CT scanner (Siemens Somatom Plus S). The 3-D transducer model was superimposed onto 3-D reconstructions of the temporal bone using ANALYZE software on a computer graphics workstation (Sun SPARCstation 10), showing the transducer "implanted" in the temporal bone. Measurements were validated using a cadaver temporal bone. This process produced images demonstrating the "fit" of the current transducer design in the mastoid region of the adult temporal bone. It permitted assessment of the proximity of surrounding structures such as the external auditory meatus, dura, or sigmoid sinus. Preliminary cadaver validation measurements confirmed the accuracy of this method. Three-dimensional CT is a feasible method for preoperative planning of the surgical implantation of devices in the temporal bone. This method of 3-D test fitting will be used in the future to determine optimum orientation and size limitations for human implantable devices.

Cochlear Implants↗
PubMed1993

Effect of KTP laser ablation of endochondral bone on bone healing.

The advantages of using a laser to cut a hole in the ossicular chain include increased precision, decreased likelihood of disarticulation, and elimination of noise-induced threshold shift associated with conventional drills. This study was designed to determine optimal energy settings and cooling technique to minimize tissue injury. Laser ablated holes were cut in rabbit femurs with different endostat fibers at power settings of 1.6 to 5.0 watts. Comparable burr holes were cut by a high-speed drill and the animals were sacrificed at different time intervals. Specimens were evaluated microscopically for tissue injury by the amount of cell necrosis of the surrounding osteocytes, bone marrow changes, and denaturation of bone matrix. Changes in healing were assessed by the production and ossification of the granulation tissue. Laser ablated holes created with 1.6 to 2.0 watts at 2 to 7 days demonstrated thermal damage comparable to conventionally drilled holes. At 14 to 28 days these holes demonstrated advanced healing and integrated lamellar bone. In contrast, higher power (> 3.5 watts) at 2 to 7 days demonstrated Significantly more osteocyte loss, marked bone marrow fibrosis, and bone matrix denaturation. At 14 to 28 days these holes showed evidence of delayed healing and osseous plugs not integrated with the surrounding bone.

Animals↗