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Query: UNIPROT:Q9UID3 (FFR)
 233 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using clicks with varying interstimulus intervals and coherent tone-bursts, early components of the auditory evoked potential (brain stem responses) were studied in four patients with confirmed acoustic neuroma. Abnormalities in responses appeared with shorter interstimulus intervals and with tone-bursts delivered monaurally to the involved ear; bilateral alterations occurred in one patient with brain stem displacement. The results indicate that BSR can provide a stable, independent, noninvasive measure of auditory nerve function useful in the early detection of acoustic neuroma. The results contribute to the understanding of the so-called human FFR.
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PMID:Early evoked potentials in patients with acoustic neuroma. 6 26

We recorded normal electrophysiological responses to third-octave filtered clicks from external auditory meatus (EAM) and vertex electrodes referred to coupled earlobe electrodes (forehead ground). From both vertex and EAM, polarity-sensitive responses predominated at low frequencies and exhibited characteristics of both phase-locked neural responses (frequency-following response or FFR) and cochlear microphonics (CM). The FFR-like response predominated at the vertex site and the CM-like response predominated at EAM. At high frequencies, polarity-insensitive responses closely resembled rectangular-pulse click action potentials and brainstem evoked potentials, with clearly defined N1 and V peaks recorded from EAM and vertex, respectively. As frequency was lowered, the N1 and V peak latencies increased, the peaks broadened, and the latency-intensity curves steepened with greater prolongation occurring at lower click intensities. Lowering click frequency also shortened the N1-V interval and caused the plot of N1-V interval versus click intensity to become steeper. Plots of polarity-insensitive response amplitudes and thresholds against frequency revealed a high frequency bias for both N1 and V, but the V "frequency response" was flatter. A possible explanation of the shortened N1-V interval at low click frequencies based on this flatter V "Frequency response" is presented.
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PMID:Normal short-latency electrophysiological filtered click responses recorded from vertex and external auditory meatus. 44 7

The most interesting electrode positions for recording the FFR are the Vertex and the mastoid. The response is greatest at the Vertex. At the mastoid it comes earlier and probably in a different phase. As a combined result of these relations the responses are in opposite phase with a 500 Hz stimulus, and at 400 Hz they are in-phase. The Vertex-derived response is contaminated by the Jewett waves and at the mastoid there is in addition a CM-like activity. In order to simplify the interpretation we recommend use of the Vertex only as active electrode position, with reference electrodes on the neck, which is largely neutral. A very effective stimulus is a 500 Hz tone-burst with rise-fall times of 2 msec and a plateau of 6 msec. Shorter stimuli yield a smaller response, and with longer stimulus duration, adaption becomes a problem. The Jewett wave contamination can be eliminated by means of recording the response twice with opposite stimulus polarity and subtracting the two from each other.
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PMID:Frequency following auditory brain stem responses in man. 59 34

In order to evaluate the frequency selectivity of the 500 Hz FFR we applied narrow-band masking at closely spaced center frequencies in the range 0.25 to 4 kHZ. The results show clearly that it is the apical part of the cochlea that generates the 500 Hz FFR, but the area of the basilar membrane that contributes is rather broad. It was evident that some of the masking effect that was observed in the Vertex-derived response stemmed from as yet obsure brain stem mechanisms. Examination of 3 patients with selected types of hearing impairment confirmed the masking results. When there is a low frequency loss there will still be a 500 Hz FFR and the same is true when the loss is in the medium to high frequencies. It is possible that precise determination of the latency to single waves in the response may allow a more exact prediction with regard to which location on the basilar membrane generates the response in the individual patient.
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PMID:The frequency selectivity of the 500 HZ frequency following response. 59 36

The last few years have seen the introduction of medical statistics into the curriculum for MB, BS and for the FFR. Also, an increasing number of clinical trials have considered statistics at the planning stage of the trial, rather than only at the end point. However, there is one particular aspect of medical statistics which has consistently been neglected, namely, technique in calculating survival rates for cancer patients. All too often, a direct method of calculation, see section 3.1, is used when a life table method would provide a better estimate. The life table, or actuarial method, was first described in a medical context by Greenwood (1926), and later by Merrell and Shulman (1955) and Cutler and Ederer (1958). It has however, not been explained in detail in a British journal. The objective of the present paper is to remedy, this fact so that it can be used more widely in the future in preference to a direct method.
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PMID:Calculation of survival rates by the life table and other methods. 126 Nov 98

Ten newborn kittens were deafened by systemic administration of neomycin sulfate. Profound hearing losses were documented by ABR and FFR (500 Hz) testing. At 9-17 weeks of age, the young deafened cats were unilaterally implanted with a multichannel scala tympani electrode. Six of the animals were chronically stimulated at 6 dB above electrically evoked ABR thresholds for 1 h/day for periods of 1 month or 3 months. Stimuli were charge-balanced biphasic pulses (200 microseconds/phase, 30 pps.) The remaining 4 cats underwent identical deafening and implantation schedules but were not stimulated. Results indicate that administration of neomycin in neonatal cats induced degeneration of hair cells and spiral ganglion cell loss that was bilaterally symmetrical between the two cochleas of each individual animal, although there was variation between animals in the severity of the ototoxic drug effect. In animals receiving passive (unstimulated) implants, morphometric analysis of spiral ganglion cell density showed no significant difference in ganglion cell survival between the implanted cochleas and the contralateral control ears. In contrast, animals that were chronically stimulated for 3 months showed significantly better neuronal survival in implanted and stimulated cochleas as compared to contralateral deafened control ears. The induced conservation of spiral ganglion neurons was observed consistently within the basal cochlear region near the stimulating electrodes. In more apical regions there was no significant difference between the stimulated and control cochleas. The mechanisms underlying this selective conservation of spiral ganglion neurons induced by chronic intracochlear electrical stimulation are uncertain. Since no comparable chronic stimulation studies have been conducted in adults, it is not known whether similar conservation effects could be induced in mature animals.
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PMID:Chronic intracochlear electrical stimulation induces selective survival of spiral ganglion neurons in neonatally deafened cats. 193 28

Twenty-five patients with soft tissue sarcomas were treated with Ir192 implants following wide local excision at our institution between 1982 and 1987. External beam radiotherapy was given in addition to the implant in a majority of patients. The median follow-up in these 25 patients is 36 months (12 to 75 months). Twenty patients have had no evidence of local recurrence following their primary treatment (FFR = 80%). A multivariate analysis using stepwise logistic regression was used to predict failure in 3 years or less. Potential predictors examined included age, sex, tumor location, primary versus recurrent disease, grade, histology, surgical margins, implant only versus implant plus external beam, and a ratio of the volume of tissue which received 65 Gy (TV65) to the tumor volume (TV), that is (TV65/TV). The single variable which was significantly associated with local failure by 3 years was a TV65/TV of less than one. Once this variable was entered into the analysis, no other factor proved statistically significant. Our data suggest that when attempting local control of soft tissue sarcomas with brachytherapy, the volume of tissue receiving 65 Gy (TV65) from both implant and external beam must exceed the volume of the excised lesion (TV). Since the volume of a tumor can be readily determined prior to surgical excision either by CT or MRI scanning, pre-planning of the implant volume could potentially reduce the rate of local failure.
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PMID:Local recurrence of soft tissue sarcoma following brachytherapy. 199 45

The results of treatment of 171 children with stage I-II Hodgkin's disease from two institutions with differing approaches to management have been analyzed. At the Stanford University Medical Center/Children's Hospital at Stanford (SUMC/CHaS), pathologic staging followed by extended-field radiation alone or involved-field radiation plus combination chemotherapy have been cardinal to the management policy. At St Bartholomew's Hospital/The Hospital for Sick Children at Great Ormond Street (Barts/GOS), clinical staging only has been used over the last 10 years, and involved/regional-field radiotherapy used as the treatment of choice rather than extended-field radiotherapy. Some children at each institution received combined modality therapy as primary management. Relapse among children with stage I disease was a more frequent occurrence in the Barts/GOS series than in the SUMC/CHaS group. However, the survival rates from the two centers are identical, 91% at 10 years. The following scientific-philosophic question is asked: Should one maximally stage and treat all children to increase the likelihood of a high freedom from relapse (FFR; cure) rate, or is it acceptable to minimize the initial staging and treatment, realizing that a proportion of patients will fail and require salvage/rescue therapy? With the awareness of morbidity from pathologic staging and aggressive treatment, and the favorable survival data reported from specialized centers using differing approaches, treatment strategies should be directed toward the long-term goal of cure of disease with maximal quality of life. A multidisciplinary management philosophy undertaken at a center with extensive experience in pediatric Hodgkin's disease is important to achieving this goal.
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PMID:Stage I-II pediatric Hodgkin's disease: long-term follow-up demonstrates equivalent survival rates following different management schemes. 219 15

The responses recorded from the exposed intracranial portion of the eighth nerve in man with normal hearing to short bursts of low-frequency tones (500, 1000, and 1500 Hz) consist of two components; these two components can be separated by adding and subtracting, respectively, the responses to tonebursts of opposite polarity. Subtracting the responses to tones of opposite polarity reveals a waveform that resembles the sinusoidal waveform of the stimulus (frequency-following response = FFR), while adding the responses to tones of opposite polarity reveals a slow component, the waveform of which is more variable than the frequency-following component. The initial deflection of the slow component of the response to 1000 Hz and to 1500 Hz is a positive peak followed by a slow, negative deflection, and the response to 1500-Hz tonebursts often shows a clear off-response. The slow component of the response to 500-Hz tones often has an initial negative peak followed by a slow, positive or negative wave. The temporal relationship between the stimulus tone and the frequency-following component changes only slightly when the intensity of the sound is changed, whereas the latency of the slow potential decreases with increasing stimulus intensity. The FFR can be masked by noise, and the results of masking with highpass-filtered noise indicate that the frequency-following response may be generated at a location on the basilar membrane that is tuned to a frequency that is higher than that of the stimulus tone.
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PMID:Response from the exposed intracranial human auditory nerve to low-frequency tones: basic characteristics. 254 Jan 33

These data indicate that the increment in the anti-leukemia effect, as expressed as FFR, is comparable for transplants for AML in first remission, advanced leukemia, and in persons never achieving remission. These data are consistent with the notion that the major anti-leukemia effect of HLA-identical bone marrow transplantation in AML results from an immune-mediated graft-versus-leukemia effect rather than from high doses of chemotherapy and radiation. Of course, other factors might explain these results. The superior outcome observed for transplants in first remission versus more advanced disease results not from increased anti-leukemia efficacy of transplants but rather that more persons already cured by chemotherapy receive transplants. Otherwise stated, a substantial portion of the persons cured following transplantation for AML in first remission were cured before receiving a transplant. These data have implications for other aspects of bone marrow transplantation. For example, it is suggested that transplants should be performed earlier in solid tumors when these diseases are more likely to respond to high-dose chemotherapy and radiation. Although this hypothesis may be correct, it need not necessarily be so as evidenced by these data in AML. The data we review show that bone marrow transplants in AML are of comparable anti-leukemia efficacy when performed in first remission, advanced leukemia, and initial resistant disease. Similar conclusions may apply to transplants in CML and ALL. The superior overall outcome observed with transplants in earlier leukemia results from transplanting a greater proportion of subjects already cured by chemotherapy. The increased anti-leukemia efficacy of transplants when compared with chemotherapy is compatible with an anti-leukemia effect other than that of high-dose chemotherapy and radiation. An immune-mediated graft-versus-leukemia effect is a likely explanation. Caution in predicting results of autotransplants in solid tumors is likewise necessary.
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PMID:Is transplantation in first remission AML more effective than in advanced leukemia? 261 62


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