Search PubMed⌕ Search

Biomedical subjects

F N Martin

Publications and source records attributed to F N Martin.

At least 19 recordsLinked to original sources
PubMed1998

Seventh survey of audiometric practices in the United States.

A 5-page questionnaire was sent to 500 audiologists who were randomly selected from the directory of members of the American Academy of Audiology to assess the clinical practices most commonly used by certified audiologists in the United States. Survey content was limited to only those practices and procedures routinely used by audiologists across the nation. The current results were then compared to those obtained in similar studies conducted in 1971, 1972, 1978, 1985, 1989, and 1994 to determine which clinical procedures are being retained, modified, or replaced.

American Speech-Language-Hearing Association↗
PubMed1998

Quantifying air-conducted acoustic radiation from the bone-conduction vibrator.

Sound pressure levels in the external auditory canals of 50 subjects were measured at 2000 and 4000 Hz with a bone-conduction vibrator on the forehead, the mastoid ipsilateral to the probe microphone, and the mastoid contralateral to the probe microphone. A plug was placed in the external auditory canal to minimize sound pressure levels in the external auditory canal produced by the osseotympanic mode of bone conduction. Results suggest that clinically significant false air-bone gaps (greater than 10 dB) due to acoustic radiation into the concha from the bone-conduction vibrator are most likely to occur at 4000 Hz when the bone-conduction vibrator is placed on the mastoid of the test ear. To minimize the possible confounding effects of acoustic radiation, the bone-conduction vibrator may be placed on the forehead or the mastoid contralateral to the test ear while masking the nontest ear.

Acoustics↗
PubMed1997

Audiologists' professional satisfaction.

This study was primarily designed to explore the job satisfaction of audiologists in the United States. A total of 285 audiologists completed background questions, rated statements, and answered questions about their job satisfaction. Through the use of multiple regression analyses, six statements were identified as being statistically significant in predicting job satisfaction. The most important factor was in the category of challenge.

Adult↗
PubMed1997

Auditory and tactile bone-conduction thresholds using three different oscillators.

Determination of tactile bone-conduction (BC) thresholds is essential to provide proper diagnosis of individuals with profound hearing loss. In this study, auditory and tactile BC thresholds were compared using three oscillators: the Radioear B-70-A, B-71, and B-72 with mastoid and forehead placement. Subjects included 12 adults with normal hearing (to establish auditory thresholds) and 12 adults with profound sensorineural hearing loss (to establish tactile thresholds). All 24 subjects were tested at octave intervals from 250 through 4000 Hz. As demonstrated in previous studies, tactile thresholds were lower for the low frequencies. Some differences in tactile thresholds were evinced as a function of different oscillators. One fact that emerged from this study is the lower tactile threshold with forehead placement as compared to the mastoid. While ostensibly a disadvantage to forehead BC testing, there are some clinical advantages to be gleaned from this discovery.

Acoustic Stimulation↗
PubMed1995

Linear mitochondrial genome organization in vivo in the genus Pythium.

Pulsed-field gel electrophoresis (PFGE) of isolates of Pythium oligandrum with linear mitochondrial genomes revealed a distinct band in ethidium bromide-stained gels similar in size to values estimated by restriction mapping of mitochondrial DNA (mtDNA). Southern analysis confirmed that these bands were mtDNA and indicated that linear genomes were present in unit-length size as well as multimers. Isolates of this species with circular mtDNA restriction maps also had low levels of linear mono- and multimers visualized by Southern analysis of PFGE gels. Examination of 17 additional species revealed similar results; three species had distinct linear mtDNA bands in ethidium bromide-stained gels while the remainder had linear mono- and multi-mers in lower amounts detected only by Southern analysis. Sequence analysis of an isolate of P. oligandrum with a primarily circular mitochondrial genomic map and a low amount of linear molecules revealed that the small unique region of the circular map (which corresponded to the terminal region of linear genomes) was flanked by palindromic intrastrand complementary sequences separated by a unique 194-bp sequence. Sequences with similarity to ATPase9 coding regions from other organisms were located adjacent to this region. Sequences with similarity to mitochondrial origins of replication and autonomously replicating sequences were also located in this region: their potential involvement in the generation of linear molecules is discussed.

Adenosine Triphosphatases↗
PubMed1994

Sound pressure in the external auditory canal during bone-conduction testing.

Sound pressure levels (SPLs) were measured in the external auditory canals (EACs) of 16 subjects with normal hearing and normal middle ear immittance. SPLs were the result of bone-conduction (BC) stimulation at 500, 1000, 2000, and 4000 Hz, with the oscillator placed either on the forehead or on the mastoid process. At 1000, 2000, and 4000 Hz, significantly higher SPLs were measured when the head was stimulated from the mastoid than from the forehead. When SPLs were compared between right and left EACs, forehead placement of the oscillator produced no interaural differences, while mastoid placement resulted in significantly greater EAC SPLs ipsilateral to the oscillator at 2000 and 4000 Hz. We conclude that forehead placement of a BC vibrator may help to lessen the (unwanted) contribution of the EAC to measurements of hearing sensitivity by BC.

Audiometry, Pure-Tone↗
PubMed1992

Professional attitudes regarding counseling of hearing-impaired adults.

To determine contemporary thinking regarding initial counseling of hearing-impaired adults 500 questionnaires were mailed to otologists and otolaryngologists and 500 to clinical audiologists. Usable questionnaires total 136 for the former group and 266 for the latter. Some significant differences were found in the ways clinicians saw themselves as counselors and in the needs they perceived their patients as having. Respondents reported experiencing various methods of training and possessing diverse attitudes about the effectiveness of their preparation as counselors during their professional training.

Adult↗
PubMed1991

Characterization of circular mitochondrial plasmids in three Pythium species.

Four circular plasmids, with a monomer size ranging from 3.2 to 4.94 kb, have been identified in isolates of P. aphanidermatum (two different plasmids), P. torulosum, and an unidentified echinulate isolate. The mitochondrial location has been confirmed for three of the plasmids. Each fungal isolate contained a single plasmid, present in both monomeric and oligomeric forms; plasmid monomers were present as open circles and as supercoiled forms. Restriction maps of the plasmids were dissimilar. Hybridization studies using cloned plasmids revealed no DNA sequence similarity among the different plasmids or between the plasmids and the nuclear or mitochondrial genome of the isolates from which they were recovered. Hybridization of labeled plasmid DNA to Northern transfers of mitochondrial RNA for two isolates indicate that what appears to be the predominant RNA transcript is unit length in size. For three isolates, the plasmid was retained following subculturing and was present in all asexual and sexual single-spore progeny evaluated. For one isolate of P. aphanidermatum the plasmid was unstable and was lost during subculturing.

Blotting, Northern↗
PubMed1991

Insert earphones for speech recognition testing.

Performance-intensity functions for PB word lists were run on 19 normal-hearing subjects and 15 subjects with sensorineural hearing losses. Comparisons were made between standard supra-aural earphones (TDH-49P) and insert phones (ER-3A). Results showed that, at least for the higher sensation levels where word recognition tests are usually performed, the phones may be used interchangeably. Using insert earphones for word recognition tests can have several beneficial effects with respect to cross hearing and masking.

Adult↗
PubMed1986

A modified spondee threshold procedure.

Since Martin and Sides (Asha, 1985, 27, 29-36) found that only 6% of audiologists reported actually following current ASHA guidelines for SRT testing (Asha, 1979, 21, 353-356), a comparison was made on 36 normal-hearing adults of spondee thresholds (ST) collected following strictly those guidelines (ST1) and by an experimental procedure based on the ASHA guidelines for pure-tone audiometry (Asha, 1978, 20, 297-301) (ST2). A 3-frequency pure-tone average (PTA) was also collected. Since mean HTLs differed by less than or equal to 5 db among ST1, ST2, and PTA, both ST procedures appear equally valid and interchangeable, but ST2 was considerably more efficient, requiring less time (mean savings of 139 sec/ear) and fewer word presentations (mean savings of 15 words/ear). The ST2 procedure may have clinical use with no significant compromise in validity.

Adult↗
PubMed1985

Speech reception thresholds using conventional vs high-frequency spondees in normals and in subjects with marked high-frequency sensorineural loss.

Spondee threshold (ST) estimates were obtained on 20 normal-hearing adults and 15 adults with high-frequency sensorineural hearing losses sloping off above 500 c/s at about 15-20 db/oct. Stimuli consisted of tapes of a woman's voice speaking permuted lists of 9 conventional (broadband) spondees and of 10 high-frequency-emphasis spondees developed especially for this research using a discrete-frequency analysis. For normals, the correspondence was good between the 3-frequency (.5, 1, 2 kc/s) PTA vs either list. However, for the sensorineural Ss, the mean ST for the conventional spondees was better matched to the 2-frequency PTA (av. of 2 best of .5, 1, 2 kc/s), while the high-frequency-emphasis list STs were better matched to the 3-frequency PTA. It was suggested that high-frequency-emphasis STs be used with such sloping losses and that ST-PTA reliability checks for such Ss be comparisons using a +/- 5-db criterion comparing high-frequency-emphasis STs with 3-frequency PTA. If conventional STs are collected, they should with such Ss be compared to the individual's 2-frequency PTA.

Adult↗
PubMed1983

Syllabic stress (trochaic vs. spondaic) and speech thresholds in normal and hearing-impaired children.

Speech thresholds for 6 common two-syllable words on tape with either trochaic (natural) or spondaic stress were collected from children aged 3.5-6.5 yrs, audiometrically grouped as normal-hearing (N:8), conductive (N:8) or sensorineural (N:6). Ss were further grouped as younger and older. No significant differences in mean threshold, nor in time to reach threshold, were observed for either pattern of stress or age, suggesting that audiologists may interchange spondaic with trochaic stress when measuring speech thresholds in young children, with no effect on the mean value or the efficiency of the threshold (mn of .5, 1, and 2 kc/s) or on its correlation with the pure-tone HTL.

Age Factors↗
PubMed1981

The influence of syllabic stress on children's speech reception thresholds.

One tape exemplar of each words cowboy, baseball, airplane, cupcake, popcorn, and hotdog spoken with natural (trochaic) and again with unnatural (spondaic) stress were selected from a pool to collect monaural SRTs by earphone in children. There were no significant differences due to type of stress, nor between boys and girls. Older children (N: 16, aged 5.0--6.0 yrs; SRT = --0.2 db HL) exhibited lower SRTs than younger (N: 16, aged 3.0--4.0 yrs; SRT = 3.2 db HL). It was informally observed that response, especially in younger Ss, tended (even when correct) to be at a slower rate, a condition to which the clinician should be alert.

Age Factors↗
PubMed1981

On the relationship of stapedial contraction to central masking.

The auditory masked threshold of a 1-kc/s pure tone was determined in quiet and with levels of white noise at 50-80 db SL in the non-test ear. Two groups of normal-hearing adults were tested, one (N:14, mn age = 27.4 yrs) with no history of middle-ear pathology, and another (N:12, mn age = 44.7 yrs) with the stapedial tendon severed. Significant differences in the amount of masked-threshold shift were observed, greater shifts being seen for the normal Ss, additional shifts ranging from 0.8-4.3 db as masking increased from 50-80 db SL. These differences were judged to be at least partly the result of stapedial contraction rather than having their origin entirely in central masking as often assumed.

Adolescent↗