Biomedical subjects

M Samantha Lewis

Publications and source records attributed to M Samantha Lewis.

5 recordsLinked to original sources

PubMed2006

Frequency-modulation (FM) technology as a method for improving speech perception in noise for individuals with multiple sclerosis.

Almost half of the population with multiple sclerosis (MS) complains of difficulty hearing, despite having essentially normal pure-tone thresholds. The purpose of the present investigation was to evaluate the effects of frequency-modulation (FM) technology utilization on speech perception in noise for adults with and without MS. Sentence material was presented at a constant level of 65 dBA Leq from a loudspeaker located at 0 degrees azimuth. The microphone of the FM transmitter was placed 7.5 cm from this loudspeaker. Multitalker babble was presented from four loudspeakers positioned at 45 degrees, 135 degrees, 225 degrees, and 315 degrees azimuths. The starting presentation level for the babble was 55 dBA Leq, The level of the noise was increased systematically in 1 dB steps until the subject obtained 0% key words correct on the IEEE (Institute for Electrical and Electronic Engineers) sentences. Test results revealed significant differences between the unaided and aided conditions at several signal-to-noise ratios.

Acoustic Stimulation↗

PubMed2005

The effect of hearing aids and frequency modulation technology on results from the communication profile for the hearing impaired.

Hearing impairment has been associated with decline in psychosocial function. Previous investigations have reported that the utilization of hearing aids can ameliorate these reductions in psychosocial function. To date, few investigations have examined the effects of frequency modulation technology on hearing handicap, adjustment to hearing loss, and communicative strategies. The purpose of this investigation was to examine these effects and to compare them to the benefits obtained when using hearing aids alone. Subjects ranged in age from 34 to 81 years and had mean pure-tone thresholds consistent with a bilateral moderate to severe sloping sensorineural hearing loss. All subjects wore hearing aids only and hearing aids plus FM system in a randomized fashion. The Communication Profile for the Hearing Impaired (CPHI) was administered prior to fitting the study devices and once a month for three months in each of the two conditions. A statistically significant difference between device conditions was obtained for the Importance of Communication in Work Situations subscale. Additionally, statistically significant differences over time were noted in several CPHI subscales. Despite statistical significance, none of these results were clinically significant. The implications of these results will be discussed.

Adult↗

PubMed2004

Effects of frequency modulation (FM) transmitter microphone directivity on speech perception in noise.

Frequency modulation (FM) technology can significantly improve the speech perception ability of individuals with sensorineural hearing loss (SNHL) in background noise. Previous investigations have demonstrated that the microphone design of the FM transmitter can have a significant impact on this improved speech perception. The purpose of this investigation was to compare 3 types of FM transmitter microphone designs: (a) wide angle (omnidirectional microphone), which amplifies sounds coming from all directions around the microphone equally; (b) zoom (1 directional microphone), which provides less amplification to signals coming from the rear, and (c) superzoom (2 directional microphones), which provides less amplification to signals originating from the rear and the sides. Fifteen adults with bilateral slight to moderately severe SNHL participated. Speech perception was assessed using the Hearing in Noise Test (M. Nilsson, S. Soli, and J. Sullivan, 1994). Speech spectrum shaped noise served as the noise competition. Results revealed that the best speech perception in noise was obtained when the FM transmitter was used in the zoom setting. The poorest performance was obtained when the FM transmitter was in the wide-angle mode. The clinical implications of these results are discussed.

Adult↗

PubMed2004

Speech perception in noise: directional microphones versus frequency modulation (FM) systems.

The major consequence of sensorineural hearing loss (SNHL) is communicative difficulty, especially with the addition of noise and/or reverberation. The purpose of this investigation was to compare two types of technologies that have been shown to improve the speech-perception performance of individuals with SNHL: directional microphones and frequency modulation (FM) systems. Forty-six adult subjects with slight to severe SNHL served as subjects. Speech perception was assessed using the Hearing in Noise Test (HINT) with correlated diffuse noise under five different listening conditions. Results revealed that speech perception was significantly better with the use of the FM system over that of any of the hearing aid conditions, even with the use of the directional microphone. Additionally, speech perception was significantly better with the use of two hearing aids used in conjunction with two FM receivers rather than with just one FM receiver. Directional microphone performance was significantly better than omnidirectional microphone performance. All aided listening conditions were significantly better than the unaided listening condition.

Adult↗

PubMedDate not supplied

Some effects of multiple sclerosis on speech perception in noise: Preliminary findings.

The present investigation examined speech perception in noise of adults with and without multiple sclerosis (MS). Institute of Electrical and Electronic Engineers (IEEE) sentences were presented at a constant level of 65 dBA L(eq) (equivalent continuous noise level [4 dB exchange rate]) from a loudspeaker located at 0-degree horizontal azimuth and 1.2 m from the study participant. Uncorrelated multitalker babble was presented from four loudspeakers positioned at 45-, 135-, 225-, and 315-degree azimuths and 1.7 m from the study participant. The starting presentation level for the babble was 55 dBA L(eq). The level of the babble was increased systematically in 1 dB steps until the subject obtained 0% key words correct on the IEEE sentences. Results revealed a significant difference in speech perception between the two groups at nine signal-to-noise ratios. Some clinical implications of these results are discussed.

Adult↗