Sumiko Takayanagi

Examination of the Neighborhood Activation Theory in Normal and Hearing-impaired Listeners

Objective E-periments were conducted to e-amine the effects of le-ical information on word recognition among normal hearing listeners and individuals with sensorineural hearing loss. The le-ical factors of interest were incorporated in the Neighborhood Activation Model (NAM). Central to this model is the concept that words are recognized relationally in the conte-t of other phonemically similar words. NAM suggests that words in the mental le-icon are organized into similarity neighborhoods and the listener is required to select the target word from competing le-ical items. Two structural characteristics of similarity neighborhoods that influence word recognition have been identified; “neighborhood density” or the number of phonemically similar words (neighbors) for a particular target item and “neighborhood frequency” or the average frequency of occurrence of all the items within a neighborhood. A third le-ical factor, “word frequency” or the frequency of occurrence of a target word in the language, is assumed to optimize the word recognition process by biasing the system toward choosing a high frequency over a low frequency word. Design Three e-periments were performed. In the initial e-periments, word recognition for consonant-vowel-consonant (CVC) monosyllables was assessed in young normal hearing listeners by systematically partitioning the items into the eight possible le-ical conditions that could be created by two levels of the three le-ical factors, word frequency (high and low), neighborhood density (high and low), and average neighborhood frequency (high and low). Neighborhood structure and word frequency were estimated computationally using a large, on-line le-icon-based Webster’s Pocket Dictionary. From this program 400 highly familiar, monosyllables were selected and partitioned into eight orthogonal le-ical groups (50 words/group). The 400 words were presented randomly to normal hearing listeners in speech-shaped noise (E-periment 1) and “in quiet” (E-periment 2) as well as to an elderly group of listeners with sensorineural hearing loss in the speech-shaped noise (E-periment 3). Results The results of three e-periments verified predictions of NAM in both normal hearing and hearing-impaired listeners. In each e-periment, words from low density neighborhoods were recognized more accurately than those from high density neighborhoods. The presence of high frequency neighbors (average neighborhood frequency) produced poorer recognition performance than comparable conditions with low frequency neighbors. Word frequency was found to have a highly significant effect on word recognition. Le-ical conditions with high word frequencies produced higher performance scores than conditions with low frequency words. Conclusion The results supported the basic tenets of NAM theory and identified both neighborhood structural properties and word frequency as significant le-ical factors affecting word recognition when listening in noise and “in quiet.” The results of the third e-periment permit e-tension of NAM theory to individuals with sensorineural hearing loss. Future development of speech recognition tests should allow for the effects of higher level cognitive (le-ical) factors on lower level phonemic processing.

Parental protectiveness and unprotected sexual activity among Latino adolescent mothers and fathers

Latino pregnant and parenting adolescents living in inner cities are one of the populations at risk for acquiring HIV. Although teen parenthood has been predominantly looked at with a focus on potential adverse physical, emotional, and socioeconomic outcomes for the mother and child; a growing body of literature has documented the strengths and resiliency of young parents. Respeto/Proteger: Respecting and Protecting Our Relationships is a culturally rooted couple-focused and asset-based HIV prevention program developed for young Latino parents. In this program, parental protectiveness (defined as the parent-child emotional attachment that positively influences parental behavior) is viewed as an intrinsic and developing critical factor that supports resiliency and motivates behavioral change. The primary purpose of this article is to describe the longitudinal randomized study evaluating the effect of this intervention on unprotected vaginal sex 6 months post intervention and to determine whether parental protectiveness had a moderating effect on the intervention. The unique features of our database allow for examination of both individual and couple outcomes.

Couple-Focused Human Immunodeficiency Virus Prevention for Young Latino Parents: Randomized Clinical Trial of Efficacy and Sustainability

OBJECTIVE To evaluate the efficacy and sustainability of a couple-focused human immunodeficiency virus (HIV) prevention intervention in reducing unprotected sex and increasing intent to use condoms and knowledge about AIDS. DESIGN Randomized controlled trial. SETTING Urban community settings in Southern California. PARTICIPANTS Primarily Latino couples (168 couples; 336 individuals) who were aged 14 to 25 years, English or Spanish speaking, and coparenting a child at least 3 months of age. INTERVENTION A 12-hour theory-based, couple-focused HIV prevention program culturally tailored for young Latino parents, with emphasis on family protection, skill building, and issues related to gender and power. The 1½-hour control condition provided basic HIV-AIDS information. MAIN OUTCOME MEASURES Primary outcome measures included self-report of condom use during the past 3 months; secondary, intent to use condoms and knowledge about AIDS. RESULTS The HIV prevention intervention reduced the proportion of unprotected sex episodes (odds ratio, 0.87 per month from baseline to 6 months; 95% confidence interval [CI], 0.82-0.93) and increased intent to use condoms (slope increase, 0.20; 95% CI, 0.04-0.37) at the 6-month follow-up; however, these effects were not sustained at 12 months. Knowledge about AIDS was increased in both groups from baseline to 6 months (slope estimate, 0.57; 95% CI, 0.47-0.67) and was maintained in the intervention group only through 12 months. Female participants in both groups had higher intent to use condoms and knowledge about AIDS than male participants (P ≤ .01). CONCLUSIONS The couple-focused HIV prevention intervention reduced risky sexual behaviors and improved intent to use condoms among young Latino parents at the 6-month evaluation. A maintenance program is needed to improve the sustainability of effects over time.

CNE Article: Pain After Lung Transplant: High-Frequency Chest Wall Oscillation vs Chest Physiotherapy

Background Chest physiotherapy and high-frequency chest wall oscillation (HFCWO) are routinely used after lung transplant to facilitate removal of secretions. To date, no studies have been done to investigate which therapy is more comfortable and preferred by lung transplant recipients. Patients who have less pain may mobilize secretions, heal, and recover faster. Objectives To compare effects of HFCWO versus chest physiotherapy on pain and preference in lung transplant recipients. Methods In a 2-group experimental, repeated-measures design, 45 lung transplant recipients (27 single lung, 18 bilateral) were randomized to chest physiotherapy (10 AM, 2 PM) followed by HFCWO (6 PM, 10 PM; group 1, n=22) or vice versa (group 2, n=23) on postoperative day 3. A verbal numeric rating scale was used to measure pain before and after treatment. At the end of the treatment sequence, a 4-item patient survey was administered to assess treatment preference, pain, and effectiveness. Data were analyzed with χ(2) and t tests and repeated-measures analysis of variance. Results A significant interaction was found between mean difference in pain scores from before to after treatment and treatment method; pain scores decreased more when HFCWO was done at 10 AM and 6 PM (P =.04). Bilateral transplant recipients showed a significant preference for HFCWO over chest physiotherapy (11 [85%] vs 2 [15%], P=.01). However, single lung recipients showed no significant difference in preference between the 2 treatments (11 [42%] vs 14 [54%]). Conclusions HFCWO seems to provide greater decreases in pain scores than does chest physiotherapy. Bilateral lung transplant recipients preferred HFCWO to chest physiotherapy. HFCWO may be an effective, feasible alternative to chest physiotherapy. (American Journal of Critical Care. 2013;22:115-125).

AN EXAMINATION OF GRADUATE STUDENTS' STATISTICAL JUDGMENTS: STATISTICAL AND FUZZY SET APPROACHES

The present study examined how statistical significance levels are treated and interpreted by graduate students who use hypothesis-testing in their scientific investigation. To test underlying psychological aspects of hypothesis-testing, the idea of fuzzy set theory was employed to identify the uncertain points in judgments. 34 graduate students in a psychology department made judgments about hypothetical statistical decisions. The results indicated that (1) the majority of these students treated significance levels on a continuum and rated them according to the magnitude of statistical significance; (2) the subjects shifted their decisions based on the types of hypothetical scenarios but not by the sample sizes; instead, they interpreted a smaller sample size as being less reliable. (3) The subjects frequently chose formally used statistical terms, e.g., Significant and Not Significant, more than graduated verbal expressions, e.g., Marginally Significant and Borderline Significant; and (4) the Fuzziness (degree of confidence in decision-making) was dependent on individuals and existed more in the critical points of transition where judgments are most difficult. The Fuzziness Index illustrated the subtle shifts of human decision-making patterns in statistical judgments. Underlying decision uncertainties and difficulties can be illustrated by functions generated from fuzzy set theory, which may more closely resemble human psychological mechanism. This integrative study of fuzzy set theory and behavioral measurements appears to provide a technique that is more natural for examining and understanding imprecise boundaries of human decisions.

Effects of lexical and talker variability factors on spoken word recognition in native and non‐native, normal and hearing‐impaired listeners

The effects of lexical difficulty and talker variability on word recognition were examined in four groups of listeners: native English/normal hearing; native English/hearing impaired; non‐native English/normal hearing; and non‐native English/hearing impaired (hearing level matched to the native hearing impaired). Lexical difficulty was measured by the difference in performance to 75 lexically ‘‘easy’’ and ‘‘hard’’ words based on word frequency and Neighborhood Activation Theory [Luce and Pisoni (1998)]. The effect of talker variability was measured by the difference in performance between single and multiple talker (nine talkers) conditions. The familiarity of the 150 words was rated on a seven‐point scale. An up–down adaptive procedure was used to determine the sound pressure level for 50% performance. Non‐native listeners in both normal and hearing‐impaired groups required a greater intensity for equal intelligibility than for the comparative native normal and hearing‐impaired listeners. Results, howeve...

Structural equation modeling applied to the prediction of word identification accuracy

Five structural equation models (SEMs) were developed to examine explicitly the relative contribution of experiential (subjective frequency and word age of acquisition) and word similarity (lexical equivalence class size and phoneme equivalence class size) factors on word identification accuracy (WIA). WIA (percent word correct scores and word cost scores) was measured for 184 monosyllabic words under five presentation conditions: (1) visual‐only speech; (2) high intelligibility vocoded auditory‐only speech; (3) low intelligibility vocoded auditory‐only speech; (4) high intelligibility vocoded audiovisual speech; and (5) low intelligibility vocoded audiovisual speech. The results showed that each factor can be treated as an isolated factor and can be measured explicitly. Furthermore, the relative strengths of their contributions varied as a function of intelligibility and the estimation power of the predictor variables. In addition, two models were developed to estimate audiovisual (conditions 4 and 5) WIA from experiential, visual‐ and auditory‐similarity factors. Only the SEM of condition 4 fit the data, and the experiential and auditory factors contributed equally, but the visual factor did not contribute much to the WIA in this model. Advantages and limitations of SEM will be discussed.

Structural equation modeling for estimating the identification accuracy and detection time latency of English monosyllabic words

Structural equation modeling (SEM) was used to examine the statistical structure among sets of experiential (word age of acquisition and subjective familiarity) and lexical similarity (lexical equivalence class size and neighborhood density) variables for word identification and reaction time latency tasks. Stimuli were 240 vocoded monosyllabic English words with reduced intelligibility and altered similarity relationships. Participants detected a target word following a prime and on every trial reported the prime. The identification accuracy was estimated by words and phonemes correct, and detection latency was estimated by trimmed and harmonic mean RTs. A parsimonious SEM was chosen in terms of the chi‐square and model fit indices that determine whether the models adequately described the particular associations of variables/interfactor relationships. The variable/factor error variances were constrained to be uncorrelated with each other in order to evaluate effects independently. A bootstrapping techni...

Information theory and variance estimation techniques in the analysis of category rating and paired comparisons

Speech clarity judgments of bandpass filtered sentences were measured by category rating and paired comparisons in five age groups—4, 5, 6, 7, and 8 years old, and adults [data for children were provided from Eisenberg and Dirks, J. Speech Hearing Res. 38, 1157–1167 (1995)]. The judgment data within each age group were subjected to information theory and variance estimation analytical techniques in order to investigate developmental differences in task performance capability. All response variability was converted into equivalent signal detection ‘‘error’’ components, representing the ability of subjects in a given age group to perform a given psychophysical procedure. Preliminary results revealed a different developmental trend for each psychophysical procedure. For category rating, children 4 to 6 years of age exhibited higher error components in their responses, suggesting reduced capability to extract information compared with adults. In contrast, children as young as 5 years of age were approaching a...