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At least 199 records · Page 11Linked to original sources
PubMed1998

The National Acoustic Laboratories' procedure for selecting the saturation sound pressure level of hearing aids: theoretical derivation.

This paper presents the derivation of a procedure for prescribing the saturation sound pressure level (SSPL) of hearing aids. The procedure is designed to be used with either measured values of loudness discomfort level (LDL) or with hearing threshold values alone. SSPL needs to be low enough to prevent the hearing aid from causing loudness discomfort to the aid wearer but high enough to prevent the hearing aid from being excessively saturated by speech. The maximum SSPL likely to be acceptable can be predicted by measuring LDL or by estimating LDL from hearing thresholds. The minimum SSPL likely to be acceptable can be predicted by calculating, for any particular hearing loss, the amount of gain likely to be needed and hence the SSPL needed if the speech input signal is continuous discourse at an overall level of 75 dB SPL. The midpoint between the minimum and maximum acceptable SSPL values is defined as the optimal or prescribed SSPL, and the three frequency average (3FA; 500, 1000, and 2000 Hz) value of this can be predicted from the 3FA hearing thresholds. Alternatively, the SSPL prescription at each frequency can be prescribed on the basis of the hearing aid gain at each frequency. For either method, the SSPL prescription needs to be increased for people with a conductive component to their hearing losses. The SSPL prescription, when referred to a 2-cc coupler, needs to be decreased for infants, for deeply inserted hearing aids, for multichannel hearing aids that limit SSPL separately in each band, and possibly for nonlinear hearing aids. The 3FA SSPL prescribed for persons with a sensorineural hearing loss increases linearly from 89 dB SPL for normal hearing to 107 dB SPL for a person with a 60 dB HL 3FA loss, and then linearly again to 139 dB SPL for a person with a 120 dB HL 3FA loss. The procedure predicts that the acceptable range of SSPLs is very wide for people with mild losses but is vanishingly small for people with profound losses.

Adult↗
PubMed1993

Development and validation of laboratory procedures for preimplantation diagnosis of Duchenne muscular dystrophy.

In order to develop and validate methods for the preimplantation diagnosis of Duchenne muscular dystrophy (DMD), we have established and evaluated PCR assays for the analysis of four loci within the DMD gene and for two Y chromosome sequences in single cells. A model system using buccal cells picked from mouthwash samples has been used for an extensive evaluation of the sensitivity and specificity of the assays, and each assay has been tested in samples containing single cells, two cells, and three cells per tube. The four DMD and two Y assays have been combined in duplex and triplex reactions to enable simultaneous diagnosis of DMD and of fetal sex. One of the DMD markers is a highly polymorphic simple tandem repeat locus which produces a basic DNA profile, and provides a control for contamination by foreign DNA. Amplification of DMD or Y sequences was observed in 78 to 92% of single male cells, rising to 96% and 97% in tubes containing two or three male cells respectively. Coamplification of both a DMD and a Y sequence together occurred with a mean success of 74% in single male cells, increasing to 93% with two, and 95% with three cells per tube. With appropriate precautions, we believe that it is now possible to proceed to clinical application of these procedures.

Base Sequence↗
PubMed1987

A laboratory procedure for the induction of flashbacks.

The authors administered infusions of lactate intravenously to seven patients with a DSM-III diagnosis of posttraumatic stress disorder, six of whom also met DSM-III criteria for panic disorder. The lactate infusions resulted in flashbacks in all seven patients and panic attacks in six patients. The authors conclude that with further development intravenous lactate infusion may be used to study flashbacks and other dissociative phenomena and to determine the relationship between flashbacks and panic anxiety.

Anxiety Disorders↗