Electrical stimulation of excitable tissue: design of efficacious and safe protocols.

Electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders. An understanding of the electrochemical mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large numbers of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and maximum electrochemical potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.

https://www.annualreviews.org/doi/pdf/10.1146/annurev.bioeng.10.061807.160518

Neural stimulation and recording electrodes.

Cost Effectiveness in Health and Medicine.

THE POSITION STATEMENT The Joint Committee on Infant Hearing (JCIH) endorses early detection of and intervention for infants with hearing loss. The goal of early hearing detection and intervention (EHDI) is to maximize linguistic competence and literacy development for children who are deaf or hard of hearing. Without appropriate opportunities to learn language, these children will fall behind their hearing peers in communication, cognition, reading, and social-emotional development. Such delays may result in lower educational and employment levels in adulthood.1 To maximize the outcome for infants who are deaf or hard of hearing, the hearing of all infants should be screened at no later than 1 month of age. Those who do not pass screening should have a comprehensive audiological evaluation at no later than 3 months of age. Infants with confirmed hearing loss should receive appropriate intervention at no later than 6 months of age from health care and education professionals with expertise in hearing loss and deafness in infants and young children. Regardless of previous hearing-screening outcomes, all infants with or without risk factors should receive ongoing surveillance of communicative development beginning at 2 months of age during well-child visits in the medical home.2 EHDI systems should guarantee seamless transitions for infants and their families through this process.

/pdf/year-2007-position-statement-principles-and-guidelines-for-1m07julcke.pdf

Year 2007 position statement: Principles and guidelines for early hearing detection and intervention programs

Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as "optical biopsy," was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.

In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography

Context Cochlear implantation is a surgical alternative to traditional amplification (hearing aids) that can facilitate spoken language development in young children with severe to profound sensorineural hearing loss (SNHL). Objective To prospectively assess spoken language acquisition following cochlear implantation in young children. Design, setting, and participants Prospective, longitudinal, and multidimensional assessment of spoken language development over a 3-year period in children who underwent cochlear implantation before 5 years of age (n = 188) from 6 US centers and hearing children of similar ages (n = 97) from 2 preschools recruited between November 2002 and December 2004. Follow-up completed between November 2005 and May 2008. Main outcome measures Performance on measures of spoken language comprehension and expression (Reynell Developmental Language Scales). Results Children undergoing cochlear implantation showed greater improvement in spoken language performance (10.4; 95% confidence interval [CI], 9.6-11.2 points per year in comprehension; 8.4; 95% CI, 7.8-9.0 in expression) than would be predicted by their preimplantation baseline scores (5.4; 95% CI, 4.1-6.7, comprehension; 5.8; 95% CI, 4.6-7.0, expression), although mean scores were not restored to age-appropriate levels after 3 years. Younger age at cochlear implantation was associated with significantly steeper rate increases in comprehension (1.1; 95% CI, 0.5-1.7 points per year younger) and expression (1.0; 95% CI, 0.6-1.5 points per year younger). Similarly, each 1-year shorter history of hearing deficit was associated with steeper rate increases in comprehension (0.8; 95% CI, 0.2-1.2 points per year shorter) and expression (0.6; 95% CI, 0.2-1.0 points per year shorter). In multivariable analyses, greater residual hearing prior to cochlear implantation, higher ratings of parent-child interactions, and higher socioeconomic status were associated with greater rates of improvement in comprehension and expression. Conclusion The use of cochlear implants in young children was associated with better spoken language learning than would be predicted from their preimplantation scores.

https://jamanetwork.com/journals/jama/articlepdf/185710/joc05034_1498_1506.pdf

Spoken language development in children following cochlear implantation

Background Hearing loss affects health and quality of life. The prevalence of hearing loss may be growing because of an aging population and increasing noise exposure. However, accurate national estimates of hearing loss prevalence based on recent objective criteria are lacking. Methods We determined hearing loss prevalence among US adults and evaluated differences by demographic characteristics and known risk factors for hearing loss (smoking, noise exposure, and cardiovascular risks). A national cross-sectional survey with audiometric testing was performed. Participants were 5742 US adults aged 20 to 69 years who participated in the audiometric component of the National Health and Nutrition Examination Survey 1999-2004. The main outcome measure was 25-dB or higher hearing loss at speech frequencies (0.5, 1, 2, and 4 kHz) and at high frequencies (3, 4, and 6 kHz). Results In 2003-2004, 16.1% of US adults (29 million Americans) had speech-frequency hearing loss. In the youngest age group (20-29 years), 8.5% exhibited hearing loss, and the prevalence seems to be growing among this age group. Odds of hearing loss were 5.5-fold higher in men vs women and 70% lower in black subjects vs white subjects. Increases in hearing loss prevalence occurred earlier among participants with smoking, noise exposure, and cardiovascular risks. Conclusions Hearing loss is more prevalent among US adults than previously reported. The prevalence of US hearing loss differs across racial/ethnic groups, and our data demonstrate associations with risk factors identified in prior smaller-cohort studies. Our findings also suggest that hearing loss prevention (through modifiable risk factor reduction) and screening should begin in young adulthood.

https://jamanetwork.com/journals/jamainternalmedicine/articlepdf/414406/ioi80055_1522_1530.pdf

Prevalence of Hearing Loss and Differences by Demographic Characteristics Among US Adults: Data From the National Health and Nutrition Examination Survey, 1999-2004

Author Affiliations: Department of Epidemiology, EviMed Research Group, LLC, Goshen, Massachusetts (Dr Zilberberg); School of Public Health and Health Sciences, University of Massachusetts, Amherst (Dr Zilberberg); Jefferson School of Population Health, Thomas Jefferson University, Philadelphia, Pennsylvania (Dr Zilberberg); and School of Medicine, University of Massachusetts, Worcester (Dr Tjia). Correspondence: Dr Zilberberg, Department of Epidemiology, EviMed Research Group, LLC, PO Box 303, Goshen, MA 01032 (evimedgroup@gmail.com). Author Contributions: Dr Zilberberg had full access to all the data and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Zilberberg. Acquisition of data: Zilberberg. Analysis and interpretation of data: Zilberberg and Tjia. Drafting of the manuscript: Zilberberg. Critical revision of the manuscript for important intellectual content: Zilberberg and Tjia. Statistical analysis: Zilberberg. Financial Disclosure: None reported. Online-Only Material: The eAppendix and eTables are available at http://www.archinternmed.com.

https://jamanetwork.com/journals/jamainternalmedicine/articlepdf/1106004/ilt1114_1851_1852.pdf

Hearing Loss Prevalence in the United States

Objective: Severe to profound hearing impairment affects one-half
 to three-quarters of a million Americans. To function in a hearing
 society, hearing-impaired persons require specialized educational,
 social services, and other resources. The primary purpose of this
 study is to provide a comprehensive, national, and recent estimate of
 the economic burden of hearing impairment.Methods: We constructed a cohort-survival model to estimate the
 lifetime costs of hearing impairment. Data for the model were
 derived principally from the analyses of secondary data sources,
 including the National Health Interview Survey Hearing Loss and
 Disability Supplements (1990–91 and 1994–95), the Department of
 Education's National Longitudinal Transition Study (1987), and
 Gallaudet University's Annual Survey of Deaf and Hard of Hearing
 Youth (1997–98). These analyses were supplemented by a review of the
 literature and consultation with a four-member expert panel. Monte
 Carlo analysis was used for sensitivity testing.Results: Severe to profound hearing loss is expected to cost society $297,000 over the lifetime of an individual. Most of these losses
 (67%) are due to reduced work productivity, although the use of special
 education resources among children contributes an additional 21%.
 Life time costs for those with prelingual onset exceed 4.6 billion will
 be spent over the lifetime of persons who acquired their impairment in
 1998. The particularly high costs associated with prelingual onset
 of severe to profound hearing impairment suggest interventions aimed
 at children, such as early identification and/or aggressive medical
 intervention, may have a substantial payback.

The societal costs of severe to profound hearing loss in the united states

ContextBarriers to the use of cochlear implants in children with profound deafness
include device costs, difficulty assessing benefit, and lack of data to compare
the implant with other medical interventions.ObjectiveTo determine the quality of life and cost consequences for deaf children
who receive a cochlear implant.DesignCost-utility analysis using preintervention, postintervention, and cross-sectional
surveys conducted from July 1998 to May 2000.SettingHearing clinic at a US academic medical center.ParticipantsParents of 78 profoundly deaf children (average age, 7.5 years) who
received cochlear implants.Main Outcome MeasuresDirect and total cost to society per quality-adjusted life-year (QALY)
using the time-trade-off (TTO), visual analog scale (VAS), and Health Utilities
Index—Mark III (HUI), discounting costs and benefits 3% annually. Parents
rated their child's health state at the time of the survey and immediately
before and 1 year before implantation.ResultsRecipients had an average of 1.9 years of implant use. Mean VAS scores
increased by 0.27, from 0.59 before implantation to 0.86 at survey. In a subset
of participants, TTO scores increased by 0.22, from 0.75 to 0.97 (n = 40)
and HUI scores increased by 0.39, from 0.25 to 0.64 (n = 22). Quality-of-life
scores were no different 1 year before and immediately before implantation.
Discounted direct costs were $60,228, yielding $9029 per QALY using the TTO,
$7500 per QALY using the VAS, and $5197 per QALY using the HUI. Including
indirect costs such as reduced educational expenses, the cochlear implant
provided a savings of $53,198 per child.ConclusionsCochlear implants in profoundly deaf children have a positive effect
on quality of life at reasonable direct costs and appear to result in a net
savings to society.

/pdf/cost-utility-analysis-of-the-cochlear-implant-in-children-2lacxn1lmr.pdf

John K. Niparko

Papers

Spoken language development in children following cochlear implantation

Prevalence of Hearing Loss and Differences by Demographic Characteristics Among US Adults: Data From the National Health and Nutrition Examination Survey, 1999-2004

Hearing Loss Prevalence in the United States

The societal costs of severe to profound hearing loss in the united states

Cost-utility analysis of the cochlear implant in children.