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Biomedical subjects

F B Simmons

Publications and source records attributed to F B Simmons.

At least 19 recordsLinked to original sources
PubMed1997

Passive constriction of the upper airway during central apneas: fiberoptic and EMG investigations.

We studied five adult male patients with central sleep apnea syndrome (> 75% of the monitored events being central) during sleep using a fiberoptic scope and EMG monitoring of the superior and middle constrictors of the pharynx and the genioglossus and geniohyoid muscles. The fiberoptic investigation revealed a spontaneous decrease in the size of the airway during central apneas, without negative intrathoracic pressure or activation of the superior and middle pharyngeal constrictor muscles. We found a mean maximum decrease of 71 +/- 7% in the cross-sectional area of the airway and an absence of superior-middle pharyngeal constrictor EMG discharge. We did not observe any complete collapses of the airway.

Adult↗
PubMed1993

High-powered automobile stereos.

We measured the owner-adjusted acoustic outputs of 10 automobile stereo systems, with power ratings ranging between 150 and 600 watts. The sound levels ranged from 107 to 138 dB SPL and 84 to 108 dBA. Most of the high-intensity sound was in the 31, 62, and 125 Hz center-frequency octave bands. The mean computed noise dose, based on the vehicle owners' reported daily duration of exposure, was 108.5%. While there is clearly a risk of hearing damage in the extreme cases according to OSHA standards, the typical listening durations claimed by the stereo owners would seem to lower the risk for the majority to acceptable margins for the automobiles measured.

Automobiles↗
PubMed1990

Severity of obstructive sleep apnea.

A four-level severity scale for obstructive sleep apnea is offered using four criteria: maximum oxygen desaturation, apnea/hyponea index, symptoms of excessive day-time sleepiness, and symptoms of related cardiac disease. Oxygen desaturation and the apnea/hyponea index for 175 patients, all having had uvulopalatopharyngoplasty surgery, showed 19% mild, 33% moderate, 17% moderately severe, and 31% severe obstructive sleep apnea. There was a very poor correlation between oxygen desaturations and number of obstructive events, which demands that both be used in any estimation of disease severity.

Humans↗
PubMed1988

Comparison of electrophonic and auditory-nerve electroneural responses.

Electrophonic and auditory-nerve electroneural responses were recorded from the inferior colliculus of the cat. The electrophonic response appeared at a latency 1.0-1.5 ms later than the electroneural response, due to the time requirements for cochlear transduction. The electrophonic response also demonstrated very slow growth of response amplitude with increasing stimulus current as compared to the electroneural response. Aminoglycoside perfusion of the cochlea eliminated the electrophonic component from the evoked response record and left the electroneural component relatively unchanged, indicating that the electrophonic is an acoustic stimulus that requires an intact auditory end organ for transduction.

Animals↗
PubMed1987

Speech perception by four single-channel cochlear implant users.

Four profoundly deaf adults, each a recent recipient of a scala tympani implant, underwent auditory and auditory-visual speech comprehension evaluations. Two subjects had multiple-electrode auditory prostheses, and 2 had single-electrode implants. All subjects were tested preoperatively with a high-power hearing aid, and postoperatively with a single-channel wearable sound processor. Reported here are the results of the first formal speech recognition tests which were conducted during the 8 months after the sound processor fitting. Three subjects had used the single-channel processor on a daily basis for up to 8 months at the time of postoperative testing. The 4th subject was a nonuser. On listening tests, a comparison between pre- and post-implant scores revealed little difference for any subject. On postoperative speechreading tasks, all subjects identified medial consonant phonemes and 2-digit numerals better with stimulation than without. The 3 frequent users of the device experienced significant improvement on connected-discourse tracking, and their speechreading of videotaped and live voice CID Everyday Sentences (Davis & Silverman, 1978) was enhanced with the addition of stimulation. The nonuser was a very proficient speechreader at the outset and exhibited no significant difference on connected-discourse tracking with and without stimulation. Moreover her ability to speechread Everyday Sentences was hampered slightly by the addition of stimulation. This single-channel sound processor functioned as a sensory supplement for the 3 frequent users, but no subject was able to use the processor as a sensory substitute.

Adult↗
PubMed1987

Infant hearing screening: program implementation and validation.

Congenital and early-onset hearing losses were discovered in 6.1% of 975 Intensive Care Nursery (ICN) graduates. The methods used were neonatal screening by Crib-O-Gram (COG) and high risk register, in combination with repeated behavioral hearing tests at 1 to 3 years. This 7-year longitudinal study had follow-up hearing evaluations for a remarkably high 84% of all subjects. Significant losses that interfered with speech and language development (1000 to 8000 Hz average loss greater than 45 dB HL bilaterally) were found in 4.3% of infants. COG in combination with subsequent behavioral hearing screening was a sensitive strategy for detecting significant hearing loss: only one child was missed with this combination. Alone, COG sensitivity to significant hearing losses was 79.3%, but would have been higher had a stricter passing criterion been adopted. Behavioral hearing screenings detected bilateral hearing losses of even mild (greater than 20 dB HL) degree. Sensitivity to significant hearing losses was 82.6% and would have been improved if test frequencies greater than 3000 Hz were included in the screen. Even if screening failure occurred at 1 year of age, the age of actual confirmation of hearing loss depended on severity of the loss and ear involvement. Significant hearing losses were confirmed earlier than less severe or unilateral losses. Although behavioral screenings could be done during the first year of life, continued follow-up was required to detect progressive hearing losses.

Acoustic Stimulation↗
PubMed1986

Delayed onset hearing loss in a two-year old.

This paper describes a delayed onset sensorineural hearing loss in a baby known to have normal hearing until at least 13 months. A mild high-frequency loss was discovered quite by accident at 25 months. The bilaterally symmetrical loss progressed over the next 6 months to no measurable high-frequency hearing and a 70 dB threshold at 500 Hz. To our knowledge this is the youngest completely documented case of what has been called hereditary delayed onset hearing loss. However, in this instance, and perhaps unsuspected in others, this child had bilateral oval and round window fistulas whose repair may have not only arrested the progression of her loss, but even improved her residual hearing sensitivity.

Audiometry↗
PubMed1986

Two emerging perilymph fistula "syndromes" in children.

This paper proposes two relatively common "syndromes" seen in children with perilymph fistulas using illustrative case reports. One, a 2 1/2-year-old child with bilaterally symmetric progressive sensorineural hearing loss, was found to have bilateral oval and round window fistulas. The other was a child who presented originally with an unexplained unilateral sensorineural loss. It was only when hearing deteriorated in the opposite ear several years later that a perilymph fistula was suspected and confirmed by tympanotomy. The clinical presentations and other details of these cases diverge widely, but may represent two emerging syndromes of perilymph fistulas in children: 1. a congenital or hereditary predisposition, and the other, 2. sudden hearing loss in the "good" ear of children with an unexplained sensorineural hearing loss in the opposite ear.

Audiometry↗
PubMed1985

Palatopharyngoplasty failure, cephalometric roentgenograms, and obstructive sleep apnea.

Nine patients with obstructive sleep apnea who underwent unsuccessful palatopharyngoplasty (PPP) as documented by polygraphic monitoring had abnormal cephalometric roentgenogram measurements. Findings indicated a small posterior airway space and inferiorly placed hyoid bone. Cephalometry performed with appropriate techniques to investigate soft tissue location should be obtained systematically in obstructive sleep apneic patients before any surgery is performed. The roentgenogram finding is a helpful guide in deciding whether PPP alone or PPP in combination with other surgical procedures would be more efficacious.

Adult↗
PubMed1984

Interaction of cortical evoked potentials to electric and acoustic stimuli.

Evoked potentials to a dichotic stimulus composed of either (1) two binaurally presented tone pips or (2) one tone pip and an electrical pulse to the auditory nerve are recorded from the primary auditory cortex of barbiturate anesthetized cats. The composite stimulus is delivered as a time delayed pair where the interstimulus interval (25 ms) is within the relative refractory period of the evoked potential to either stimulus alone. The amplitude of the cortical potential to the trailing stimulus is compared with its single amplitude as the frequency of the trailing tone pip is changed from 250 Hz through 40 kHz. There is an optimal frequency range over which the trailing stimulus is suppressed and this range appears directly related to the current of a preceding electrical pulse. The frequency of maximum suppression shifts according to the position of the electrode in the nerve. In some experiments secondary maxima develop, suggesting stimulus current spread from fibers of one cochlear turn into fibers from another turn.

Animals↗
PubMed1984

The palatopharyngoplasty operation for snoring and sleep apnea: an interim report.

We performed palatopharyngoplasty operations on 155 patients as of June 1, 1983, and have 4-month clinical follow-ups on 123 patients. Forty-nine have had repeat polysomnograms (through September 1983) that continue to show the operation is about 50% effective in curing or considerably improving obstructive sleep apnea. Symptomatic (clinical) results in these same patients are much better than 50% and may be the reason why we have had considerable difficulty in obtaining sleep study follow-ups. Snoring was eliminated or much improved in 93% of all patients and 95% of patients without serious obstructive sleep apnea. Daytime symptoms, if any, were improved in 64%. Some form of preoperative sleep study is mandatory in all patients. Two thirds of patients who present with the complaint of snoring and none of the classic symptoms of apnea actually do have total airway obstructions during sleep.

Humans↗
PubMed1984

Comparison of electrode sites in electrical stimulation of the cochlea.

There is considerable controversy about the "best" location for single channel cochlear implant electrodes. We measured the electrically induced auditory brain stem response (EABR) in a series of normal to totally denervated cat ears in response to promontory (P), round window (RW) and scala tympani (ST) stimulation. The status of the ganglion cell population was then assessed by light microscopy. In ears with light to medium ganglion cell loss the ST EABR yielded the most definitive input-output functions. RW responses were present at increased thresholds and smaller peak amplitudes. P responses were worse or even missing completely. In severely damaged ears, including some with no detectable ganglion cells, ST and RW EABRs were both markedly reduced with considerable overlap between the two sites. P responses, when present, were almost buried in the electrical noise near threshold. Extrapolating these results to humans suggests that when ganglion cell loss is very severe the RW or ST is an acceptable stimulation site. When ganglion cell loss is moderate or better, ST electrodes are superior.

Animals↗
PubMed1984

Five cases of near-miss sudden infant death syndrome and development of obstructive sleep apnea syndrome.

Five full-term infants were referred for "near miss" sudden infant death syndrome events, which occurred between 3 and 12 weeks of age. After a complete pediatric evaluation and 24-hour polygraphic monitoring, each infant was monitored at home with a cardiorespiratory monitor. Each was followed regularly (with repeat polygraphic recordings) up to 4 years of age. All five infants developed heavy snoring at night and symptoms of obstructive sleep apnea syndrome. The diagnosis of obstructive sleep apnea syndrome was confirmed by polygraphic recordings; surgery was recommended. Four of the five children underwent adenoidectomies between 3 and 4 years of age, and this significantly improved their condition. These five cases are the first polygraphically documented histories of the development of obstructive sleep apnea syndrome.

Adenoidectomy↗