The Effect of Beat Frequency Vibration on Sleep Latency and Neural Complexity: A Pilot Study.

Insomnia affects millions of people worldwide, and non-pharmacological treatment options are limited. A bed excited with multiple vibration sources was used to explore beat frequency vibration (BFV) as a non-pharmacological treatment for insomnia. A repeated measures design pilot study of 14 participants with mild-moderate insomnia symptom severity (self-reported on the Insomnia Severity Index) was conducted to determine the effects of BFV, and traditional standing wave vibration (SWV) on sleep latency and sleep electrocortical activity. Participants were monitored using high-density electroencephalography (HD-EEG). Sleep latency was compared between treatment conditions. A trend of decreasing sleep latency due to BFV was found for unequivocal sleep latency (p ≤ 0.068). Neural complexity during wake, N1, and N2 stages were compared using Multi-Scale Sample Entropy (MSE), which demonstrated significantly lower MSE between wake and N2 stages (p ≤ 0.002). During N2 sleep, BFV showed lower MSE than the control session in the left frontoparietal region. As a measure of information integration, reduced entropy may indicate that BFV decreases conscious awareness during deeper stages of sleep. SWV caused reduced alpha activity and increased delta activity during wake. BFV caused increased delta activity during N2 sleep. These preliminary results suggest that BFV may help decrease sleep latency, reduce conscious awareness, and increase sleep drive expression during deeper stages of sleep. SWV may be beneficial for decreasing expression of arousal and increasing expression of sleep drive during wake, implying that beat frequency vibration may be beneficial to sleep.

Psychometrically equivalent bisyllabic words for speech recognition threshold testing in Vietnamese.

OBJECTIVE: This study identified, digitally recorded, edited and evaluated 89 bisyllabic Vietnamese words with the goal of identifying homogeneous words that could be used to measure the speech recognition threshold (SRT) in native talkers of Vietnamese. DESIGN: Native male and female talker productions of 89 Vietnamese bisyllabic words were recorded, edited and then presented at intensities ranging from -10 to 20 dBHL. Logistic regression was used to identify the best words for measuring the SRT. Forty-eight words were selected and digitally edited to have 50% intelligibility at a level equal to the mean pure-tone average (PTA) for normally hearing participants (5.2 dBHL). STUDY SAMPLE: Twenty normally hearing native Vietnamese participants listened to and repeated bisyllabic Vietnamese words at intensities ranging from -10 to 20 dBHL. RESULTS: A total of 48 male and female talker recordings of bisyllabic words with steep psychometric functions (>9.0%/dB) were chosen for the final bisyllabic SRT list. Only words homogeneous with respect to threshold audibility with steep psychometric function slopes were chosen for the final list. CONCLUSIONS: Digital recordings of bisyllabic Vietnamese words are now available for use in measuring the SRT for patients whose native language is Vietnamese.

Masking level difference in an adaptive procedure for clinical investigation.

OBJECTIVE: Masking level difference (MLD) tests are an established component of auditory processing test batteries; however, normative data for these tests vary according to procedure. The purpose of this study was to establish a standardized procedure for clinical use in the measurement of the MLD. DESIGN: A newly developed computer software program using both an adaptive procedure (MLDA) and a Békésy procedure (MLDB) was evaluated in this study. STUDY SAMPLE: Forty normal-hearing, native-English speaking adults between the ages of 18 and 26 years were included in the study. RESULTS: Both the MLDA and MLDB procedures showed statistically significant sex differences in the masked thresholds used to obtain the MLD, but not for the calculated MLD value; hence, normative data need not be reported separately by sex. Furthermore, statistically significant differences between procedures were observed, with the MLDA procedure producing higher MLDs. The MLDA procedure permitted a d' analysis, which could not be determined using the MLDB procedure. For MLDA, d' = 1.4, test sensitivity = 96.4%, and test specificity = 60.3%. CONCLUSIONS: The results of this study indicate that MLDA is a more efficient testing procedure due to MLDA's higher MLD average and the statistical data available (d', and measures of sensitivity and specificity).

Hearing screening outcomes for persons with intellectual disability: a preliminary report of findings from the 2005 Special Olympics World Winter Games.

The Special Olympics Healthy Hearing Program provides a unique opportunity to determine the hearing service needs of individuals with mild intellectual disabilities participating in athletic endeavors in countries throughout the world. The Healthy Hearing Program screened 855 of 1800 athletes with intellectual disability over a period of a week at Nagano, Japan. Of 855 athletes screened, 58% passed the DPOAE screen and therefore required no further testing. Of the remaining 42%, 186 did not pass pure-tone screening. This number of athletes represents 21.8% of all athletes screened. Tympanometry outcomes for the 186 athletes failing pure-tone screening showed 56% (104) also failing this measure of middle-ear function. 65% of these 104 athletes' outer ear canals were blocked/partially-blocked with cerumen. This amount is in contrast to the 38% presence of cerumen for the 82 athletes failing pure-tone screening but passing tympanometry.

Psychometrically equivalent Russian speech audiometry materials by male and female talkers.

Despite the large number of individuals who speak Russian, only a limited number of high-quality speech audiometry materials are available in a standard dialect of Russian. Thus, the purpose of this study was to develop and evaluate speech audiometry materials that can be used to measure word recognition and SRT testing in quiet for native speakers of Russian. Familiar monosyllabic and bisyllabic words were digitally recorded by male and female talkers of Russian and subsequently evaluated by native listeners. Using logistic regression, psychometric functions were then calculated for all words. Selected monosyllabic words were digitally adjusted to create word recognition lists which are relatively homogeneous with respect to audibility and psychometric slope. Speech reception threshold materials were developed by selecting twenty-five bisyllabic words with relatively steep psychometric function slopes (12.1%/dB and 9.9 %/dB) and digitally equating their intensity to match the mean PTA of the native listeners. Digital recordings of the resulting psychometrically equivalent speech audiometry materials are available on compact disc.

Interactions among variables in the P300 response to a continuous performance task in normal and ADHD adults.

This study investigated the effect of variable interstimulus intervals (ISIs) in a group of normal and ADHD (attention deficit hyperactivity disorder) adults on behavioral reaction time and the auditory P300 event-related potential. This study involved 20 adult subjects with no history of ADHD and 11 adult subjects diagnosed with ADHD. The subjects were instructed to respond to the common stimuli and ignore the rare stimulus. Significant differences in the latency of the P300a, P300b, the amplitude of the P300b, and in the number of false alarms and correct rejections between ISIs were observed in the normal group. The group with ADHD failed to show any significant differences between ISIs. Psychophysical measures of hits showed significant differences for the number of hits for ISI 2 (2 sec) between the two groups. False alarms and correct rejections for all ISIs showed significant differences between groups. Significant group differences were seen for latency of the P300a and P300b at each of the three ISIs, for amplitude of the P300a and P300b for ISI 1 and ISI 3, and for the amplitude of the P300b for ISI 2. There was a greater separation in the group with ADHD between the P300a and P300b suggesting a processing lag in that group.