Otoacoustic emissions as a screening test for hearing impairment in children recovering from acute bacterial meningitis

OBJECTIVES: To study the efficacy of otoacoustic emissions (OAEs) as a screening test for hearing impairment in children with acute bacterial meningitis. Hearing tests were performed before discharge from the hospital in an attempt to improve coverage and avoid delays in the diagnosis of postmeningitic hearing loss. METHODS: Children with bacterial meningitis were recruited from 21 centers. In the 48 hours before discharge from the hospital, all patients underwent a thorough audiologic assessment consisting of transient evoked OAEs, auditory brainstem responses (ABRs), otoscopy, and tympanometry. Hearing loss was defined as ABR threshold >/=30 dB. The results of OAE screening were compared with the gold standard of ABR threshold. RESULTS: Of 124 children recruited, we were able to perform both OAEs and ABRs on 110 children. Seven (6.3%) of the 110 children had ABR threshold >/=30 dB; 2 had sensorineural hearing loss and 5 had conductive hearing loss. At follow-up, hearing loss persisted in both cases of sensorineural hearing loss and no new cases were identified. All 7 children with hearing loss failed the OAE screening test. Ninety-four children with normal hearing thresholds passed the test, and 9 failed. Thus, the screening test had a sensitivity of 1.00 (95% confidence interval, 0.59 to 1.00), a specificity of 0.91 (0.85 to 0.97), a positive predictive value of 0. 44 (0.20 to 0.70), and a negative predictive value of 1.00 (0.96 to 1.00). CONCLUSIONS: OAE screening in children recovering from meningitis was found to be feasible and effective. The test was highly sensitive and reasonably specific. Inpatient OAE screening should allow early diagnosis of postmeningitic hearing loss and prompt auditory rehabilitation.     

Iron-induced oxidative DNA damage and its repair in primary rat hepatocyte culture

Iron-overload diseases frequently develop hepatocellular carcinoma. The genotoxic mechanism whereby iron is involved in hepatocarcinogenesis might involve an oxidative process via the intermediate production of reactive oxygen species. This was presently investigated by examining kinetics of formation and repair of DNA base lesions in primary rat hepatocyte cultures supplemented with the iron chelate, ferric nitrilotriacetate Fe-NTA (10 and 100 microM). Seven DNA base oxidation products have been identified in DNA extracts by gas chromatography- mass spectrometry, which showed a predominance of oxidized-purines (8- oxo-guanine, xanthine, fapy-adenine, 2-oxo-adenine) above oxidized pyrimidines (5-OHMe-uracil, 5-OH-uracil, 5-OH-cytosine) in control cultures. All these DNA oxidation products revealed a significant dose- dependent increase at 4 to 48 h after Fe-NTA supplementation, among which fapy-adenine showed the highest increase and 5-OH-cytosine was the least prominent. Involvement of iron in this oxidative process was established by a correlation between extent in DNA oxidation and intracellular level of toxic low molecular weight iron. DNA excision- repair activity was estimated by release of DNA oxidation products in culture medium. All the seven DNA oxidation products were detected in the medium of control cultures and showed basal repair activity. This DNA repair activity was increased in a time- and dose-dependent fashion with Fe-NTA. Oxidized-pyrimidines, among which was 5-OHMe-Uracil, were preferentially repaired, which explains the low levels detected in oxidized DNA. Since oxidized bases substantially differed from one another in terms of excision rates from cellular DNA, specific excision- repair enzymes might be involved. Our findings, however, demonstrate that even though DNA repair pathways were activated in iron-loaded hepatocyte cultures, these processes were not stimulated enough to prevent an accumulation of highly mutagenic DNA oxidative products in genomic DNA. The resulting genotoxic effect of Fe-NTA might be relevant in understanding the hepatocarcinogenic evolution of iron-overload diseases.      

P300 event-related brain potential as an index of recognition response to autobiographical and recently learned information in closed-head-injury patients

Abstract

Fourteen patients who sustained a closed-head injury had their P300 (P3) measured in a visual recognition paradigm to test the use of P3 as an index of recognition in this population. Subjects participated in recognition tests for both autobiographical information (their birthday) and for a word list learned immediately before testing while event-related potentials were recorded. Within-subjects tests were used to determine that the P3 amplitude in response to oddball items (the subject's birthday and the studied word list) was larger than the P3 in response to non-oddball items for 9 of 11 subjects in the autobiographical condition, and 6 of 12 subjects in the word-list condition. Averaged P3s to oddball items were also larger than P3s to non-oddball items in standard group tests (p < .001), suggesting this difference can be used as an index of recognition in closed-head-injury patients.     

Validity Indicators Within the Wisconsin Card Sorting Test: Application of New and Previously Researched Multivariate Procedures in Multiple Traumatic Brain Injury Samples

The Wisconsin Card Sorting Test (WCST) is a popular neuropsychological measure of executive dysfunction that has been researched with regard to invalid performances, a subset of which in a forensic context could be associated with malingering. In the first of three studies, WCST multivariate approaches identified in prior research (Bernard, McGrath, & Houston, 1996; Suhr & Boyer, 1999), as well as newly created variables, were used to differentiate 33 chronic traumatic brain injury (TBI) patients with good effort and 27 patients with probable insufficient effort (IE). Newly created variables that were derived logically based upon hypotheses regarding strategies that might be employed by malingerers were not effective in differentiating TBI and IE groups. Application of previously researched validity indicators based upon commonly used WCST variables, individually, and within new logistic regression findings were reasonably effective in differentiating TBI and IE groups. In order to determine whether results would vary in different TBI samples, these validity indicators were examined in Study 2 with 75 moderate and severe, acute TBI rehabilitation patients whose posttraumatic amnesia had just resolved. Statistically significant differences were present between the IE group of Study 1 and the rehabilitation patient group of Study 2 on failures to maintain set, number of trials to achieve first correct category, and number of categories completed. All these measures were performed more poorly by the IE group. However, previously used multivariate approaches and the logistic regression analysis developed in Study 1 ranged widely in the degree to which Study 2's more acute rehabilitation patients were correctly classified. Specifically, the discriminant function of Bernard and colleagues correctly classified 73% and the Suhr and Boyer logistic regression correctly classified 75% of the Study 2 participants. The Study 1 logistic regression classified 97% of the Study 2 participants correctly. In Study 3, 130 mild to severe TBI patients in the VA system were studied. The Study 1 IE group performed significantly worse than the more acute and more severe VA TBI group on all 10 common WCST variables of interest. Application of the three multivariate procedures resulted in good to excellent classification rates: Suhr and Boyer logistic regression 85%, Bernard et al. discriminant function 85%, and Study 1 logistic regression 99%. The aggregate discussion of the three studies focuses on apparent differences in samples associated with varying degrees of success in identifying TBI patients. Application of these validity indicators in forensic situations should consider that some of these multivariate approaches possess possible classification limitations associated with chronicity and severity of the reported TBI. Only the Study 1 logistic regression demonstrated improved classification rates with the more acute and severe patients of Study 2 and Study 3. As with all validity indicators, use of any WCST IE criteria in solation would not be appropriate.     

Normative Clinical Relationships Between Orientation and Memory: Age as an Important Moderator Variable

The present study examined the relationship between memory and orientation to time, place, and personal and general information, as moderated by age, education, and simple attentional ability. A heterogeneous sample of 312 clinical referrals was divided into four groups, according to delayed memory functioning. Patients with globally good, globally poor, poor visual, and poor auditory memory were at differential risk of being disoriented, with the globally poor memory patients having the greatest risk. Overall, poorly oriented patients were older and less educated, with worse recall of digits backward. Discriminant Function Analysis selected visual and auditory memory and age as predictors of orientation. Normative tables stratified by age and memory performance are presented.     

Patterns of Motivation and Ongoing Exercise Activity in Cardiac Rehabilitation Settings: A 24-Month Exploration from the TEACH Study

Background  

Few studies have explored exercise and motivational patterns of cardiac rehabilitation patients in the long term.     

Role of Radiation Therapy in Gastric Cancer

Annals of Surgical Oncology - The only curative treatment for localised gastric cancer is surgical resection. However, survival outcomes post-surgery alone remain poor, particularly in those with...