EFFECTS OF SIGNAL PROCESSING ON SPEECH UNDERSTANDING IN QUIET AND INNOISE



NIH GUIDE, Volume 23, Number 3, January 21, 1994



PA NUMBER:  PA-94-030



P.T. 34



Keywords:

  Communicative Disorders, Speech 

  Hearing 

  Prosthetic Device, Hearing 



National Institute on Deafness and Other Communication Disorders



PURPOSE



The National Institute on Deafness and Other Communication Disorders

(NIDCD) invites applications for support of research addressing the

effects of signal processing on speech understanding in quiet and in

noise.  The goal of this Program Announcement (PA) is to stimulate

basic research in a wide range of scientific disciplines to increase

our understanding of normal and impaired auditory systems' responses

to speech sounds that are processed through hearing aids, especially

in the presence of background noise.  This information will

ultimately help to guide the development of improved hearing aids.



HEALTHY PEOPLE 2000



The Public Health Service (PHS) is committed to achieving the health

promotion and disease prevention objectives of "Healthy People 2000,"

a PHS-led national activity for setting priority areas.  This PA,

Effects of Signal Processing on Speech Understanding in Quiet and in

Noise, is related to the priority area of diabetes and chronic

disabling diseases.  Potential applicants may obtain a copy of

"Healthy People 2000" (Full Report:  Stock No. 017-001-11474-0) or

"Healthy People 2000" (Summary Report:  Stock No. 017-001-11473-1)

through the Superintendent of Documents, Government Printing Office,

Washington, DC 20402-9325 (telephone 202-783-3238).



ELIGIBILITY REQUIREMENTS



Applications may be submitted by domestic and foreign for-profit and

non-profit organizations, such as universities, colleges, hospitals,

laboratories, units of state or local governments, and eligible

agencies of the Federal government.  Foreign institutions are not

eligible to apply for the First Independent Research Support and

Transition (FIRST) (R29) award.  Applications from minority

individuals and women are encouraged.



MECHANISM OF SUPPORT



Support mechanisms appropriate for this announcement include the

individual research project grant (R01) and the FIRST (R29) award.



RESEARCH OBJECTIVES



Background



Hearing aids continue to be the principal management of choice for

most people with sensorineural hearing loss.  Unfortunately, hearing

aids often provide limited benefit, especially in noisy conditions.

Progress in the miniaturization of circuits and transducers now

allows a wide range of signal processing functions to be incorporated

into very small devices.  Many of these processing functions may

improve the understanding of speech in noisy environments.  However,

the increased signal processing potential of hearing aids may soon

surpass, or has already surpassed, the basic understanding of

audition required to utilize the technology optimally.  For example,

the information-bearing acoustic parameters and units of speech are

not yet fully understood.  Nor is it known how the characteristics of

hearing impairment (e.g., reduced or altered spectral and temporal

processing abilities, increased linearity of the auditory system)

affect the perception of various speech parameters.  Even less well

understood is how both normal and impaired auditory systems perform

under the conditions imposed by the signal processing technologies of

hearing aids (e.g., listening at high intensity levels, increased

masking, temporal and spectral changes in signals).



Studies designed to investigate the problem of hearing in noise date

back to the early development of hearing aids.  Numerous studies have

confirmed that, in contrast to individuals with normal hearing,

hearing-impaired subjects perform poorly on speech intelligibility

tasks in noisy conditions.  The cause of that poor performance has

yet to be defined adequately.  Early studies have shown that both

frequency and temporal resolution are poorer in listeners with

sensorineural hearing loss than in listeners with normal hearing.

These differences are attributed to such factors as abnormal spread

of masking, broader peripheral filtering, and longer time constants

for recovery from forward masking.  However, some recent studies also

support the possibility that the effects attributed to deficits in

frequency selectivity and temporal processing in hearing-impaired

listeners may in fact result from abnormal rates of growth of

response to acoustic stimuli in the impaired ear.  In this view,

underlying properties of auditory filters and time constants remain

unaltered in the impaired ear, and recruitment becomes the primary

phenomenon in abnormal suprathreshold response.  Additionally, some

data suggest that the hearing-impaired subjects' poor performance can

be explained largely on the basis of differences in audibility due to

decreased hearing sensitivity, masking effects, and/or speech

presentation level.



Few studies have examined the effects of signal processing by hearing

aids on audition using either normal or hearing-impaired subjects.

It is probable that the difficulties in speech understanding

experienced by individuals with sensorineural hearing losses, which

are often associated with auditory processing abnormalities in

addition to a loss of sensitivity, may be exacerbated by the high

intensities of sound processed through hearing aids.  It is proving

to be difficult to predict how a given signal processing strategy or

circuit, with high presentation levels and many changes in temporal

and spectral characteristics, will process continually changing

speech signals.  Furthermore, the interaction of the processed

acoustic signal with the remaining capabilities of the impaired

auditory system has never been systematically explored.  A more

thorough understanding of the effects of signal processing on

audition is needed in order to guide the development of and to allow

the proper utilization of improved hearing aids.  Similarly there is

need for a better understanding of the theoretical and practical

issues of the physiologic, perceptual and communicative processes of

hearing-impaired persons under conditions relevant to the use of

hearing aids.



Research Goals and Scope



Studies are encouraged that are designed to assess the response of

individuals with normal and impaired auditory systems to sounds that

are processed through hearing aids, in the conditions normally

encountered by hearing aid users.  Noises and other experimental

variables representative of real listening environments should be

used when possible.  The use of experimental designs that minimize

the confounding effects of threshold and presentation levels on

estimates of subject performance are desirable.



Areas of research that would be responsive to this PA include, but

are not limited to:



o  studies of the influences of processing speech through hearing

aids (e.g., high presentation levels, changes in temporal and

spectral characteristics) on the understanding of speech sounds in

quiet and in noise for normal and impaired auditory systems;



o  studies in quiet and in noise designed to assess the interaction

between the processed acoustic signal and the impaired auditory

system having such features as reduced frequency selectivity, limited

dynamic range, and abnormal growth of loudness;



o  studies of methods of predicting speech recognition with hearing

aids in quiet and in noise for normal and impaired auditory systems;



o  studies designed to examine the relationship between optimal

speech spectrum audibility and loudness tolerance under conditions

relevant to hearing aid use in normal and impaired auditory systems

in quiet and in noise;



o  studies of the effects of reverberation on speech recognition

under conditions relevant to hearing aid use by normal and impaired

auditory systems in quiet and in noise;



o  studies of changes in speech recognition performance as a function

of intensity level with consideration of the factors involved in

audibility in quiet and in noise in normal and impaired auditory

systems;



o  studies of psychoacoustic performance measures (e.g.,

discrimination of spectral contrast, frequency resolution,

sensitivity to subtle temporal factors within complex sounds) under

conditions relevant to hearing aid use in normal and impaired

auditory systems in quiet and in noise.



STUDY POPULATIONS



SPECIAL INSTRUCTIONS TO APPLICANTS REGARDING IMPLEMENTATION OF NIH

POLICIES CONCERNING INCLUSION OF WOMEN AND MINORITIES IN CLINICAL

RESEARCH STUDY POPULATIONS



NIH policy is that applicants for NIH clinical research grants and

cooperative agreements are required to include minorities and women

in study populations so that research findings can be of benefit to

all persons at risk of the disease, disorder or condition under

study; special emphasis must be placed on the need for inclusion of

minorities and women in studies of diseases, disorders and conditions

which disproportionately affect them.  This policy is intended to

apply to males and females of all ages.  If women or minorities are

excluded or inadequately represented in clinical research,

particularly in proposed population-based studies, a clear compelling

rationale must be provided.



The composition of the proposed study population must be described in

terms of gender and racial/ethnic group.  In addition, gender and

racial/ethnic issues must be addressed in developing a research

design and sample size appropriate for the scientific objectives of

the study.  This information must be included in the form PHS 398 in

Sections 1-4 of the Research Plan AND summarized in Section 5, Human

Subjects.  Applicants are urged to assess carefully the feasibility

of including the broadest possible representation of minority groups.



However, NIH recognizes that it may not be feasible or appropriate in

all research projects to include representation of the full array of

United States racial/ethnic minority populations (i.e., Native

Americans [including American Indians or Alaskan Natives],

Asian/Pacific Islanders, Blacks, Hispanics).  The rationale for

studies on single minority population groups should be provided.



For the purpose of this policy, clinical research is defined as human

biomedical and behavioral studies of etiology, epidemiology,

prevention (and preventive strategies), diagnosis, or treatment of

diseases, disorders or conditions, including but not limited to

clinical trials.



The usual NIH policies concerning research on human subjects also

apply.  Basic research or clinical studies in which human tissues

cannot be identified or linked to individuals are excluded.  However,

every effort should be made to include human tissues from women and

racial/ethnic minorities when it is important to apply the results of

the study broadly, and this should be addressed by applicants.



For foreign awards, the policy on inclusion of women applies fully;

since the definition of minority differs in other countries, the

applicant must discuss the relevance of research involving foreign

population groups to the United States' populations, including

minorities.



If the required information is not contained within the application,

the application will be returned.



Peer reviewers will address specifically whether the research plan in

the application conforms to these policies.  If the representation of

women or minorities in a study design is inadequate to answer the

scientific questions(s) addressed AND the justification for the

selected study population is inadequate, it will be considered a

scientific weakness or deficiency in the study design and reflected

in assigning the priority score to the application.



All applications for clinical research submitted to NIH are required

to address these policies.  NIH funding components will not award

grants or cooperative agreements that do not comply with these

policies.



APPLICATION PROCEDURES



Applications are to be submitted on the grant application form PHS

398 (rev. 9/91) and will be accepted at the standard application

deadlines as indicated in the application kit.  The receipt dates for

applications for AIDS-related research are found in the PHS 398

instructions.



Application kits are available at most institutional offices of

sponsored research and may be obtained from the Office of Grants

Information, Division of Research Grants, National Institutes of

Health, Westwood Building, Room 449, Bethesda, MD 20892, telephone

301/594-7250.  The title and number of the announcement must be typed

in Section 2a on the face page of the application.



Applications for the FIRST Award (R29) must include at least three

sealed letters of reference attached to the face page of the original

application.  FIRST Award (R29) applications submitted without the

required number of references letters will be considered incomplete

and will be returned without review.



The completed original application and five legible copies must be

sent or delivered to:



Division of Research Grants

National Institutes of Health

Westwood Building, Room 240

Bethesda, MD  20892**



REVIEW CONSIDERATIONS



Applications will be reviewed for scientific and technical merit by

study sections of the Division of Research Grants, NIH, in accordance

with the standard NIH peer review procedures. Following

scientific-technical review, the applications will receive a

second-level review by the appropriate national advisory council.



AWARD CRITERIA



Applications will compete for available funds with all other approved

applications.  The following will be considered as funding decisions

are made:



o  quality of the proposed project as determined by peer review,

o  availability of funds, and

o  program balance among research areas of the announcement.



INQUIRIES



Written and telephone inquiries concerning this PA are encouraged.

The opportunity to clarify any issues or questions from potential

applicants is welcome.



Inquiries regarding programmatic issues may be addressed to:



Amy M. Donahue, Ph.D. or Lynn E. Huerta, Ph.D.

Division of Communication Sciences and Disorders

National Institute on Deafness and Other Communication Disorders

Executive Plaza South, Suite 400-C

6120 Executive Boulevard

Bethesda, MD  20892

Telephone:  (301) 402-3458

FAX:  (301) 402-6251



Inquiries regarding fiscal matters may be addressed to:



Sharon Hunt

Division of Extramural Activities

National Institute on Deafness and Other Communication Disorders

Executive Plaza South, Suite 400-B

6120 Executive Boulevard

Bethesda, MD  20892

Telephone:  (301) 402-0909

FAX:  (301) 402-1758



AUTHORITY AND REGULATIONS



This program is described in the Catalog of Federal Domestic

Assistance No. 93.173.  Awards are made under authorization of the

Public Health Service Act, Title IV, Part A (Public Law 78-410, as

amended by Public Law 99-158, 42 USC 241 and 285) and administered

under PHS grants policies and Federal Regulations 42 CFR 52 and 45

CFR Part 74.  This program is not subject to the intergovernmental

review requirements of Executive Order 12372 or Health Systems Agency

review.



.


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