Features a highly revealing expose on the often
tragic effects of sleep deprivation on the success
of auditory rehabilitation. Reader inquiries may be
directed to "contact us" or by faxing to
719-676-6882. Replies are for educational purposes
only, and are not to be construed as medical advice
or opinion.
Monographs in Hearing Health
SLEEP DEPRIVATION & AUDITORY REHABILITATION: A
PATIENT PRIMER
By Max S. Chartrand, M.A.,
DigiCare Hearing Research & Rehabiliation
INTRODUCTION
In the typical hearing health case history, we ask
patients about prior medical history, medications,
supplements and dosages, even such items as tobacco
and alcohol consumption, all of which can have a
profound effect on hearing health states. We
ascertain current medical care, and attempt to
determine psychosocial and special factors that may
contribute to stress levels of an individual
patient. Communicative performance and communication
breakdown information are routine, as are prior
amplification history (if any), and other oto-related
data are gathered.
Sleep deprivation, unless brought up accidentally,
however, is generally passed over, though recent
research findings indicate that such information
could provide an important piece of the larger
auditory remediation puzzle. The purpose of this
monograph is to cover some of the highlights on the
possible effects of sleep deprivation on auditory
rehabilitation found in the literature and in
research.
A key word here is “chronic”, or the repeated loss
of needed sleep in humans to maintain normal
cognitive and physical function. Another keyword is
“cognitive function”, for communication and
cognition share similar, if not significantly
overlapping, functions in the brain, and in
behavior.
HOW MUCH IS ENOUGH?
Most adults require a minimum of eight hours of
sleep for normal cognitive function. Others can
function well on 7 hours, while yet others may
require 9 hours. Of courser, this estimate is
assuming a state of restful sleep, complete with a
requisite period of rapid eye movement (REM). This
would not include most artificially induced sleep,
depending on the waking side effects of the
medication.
Some adults, depending on metabolic factors, may
perform well on slightly less. However, veritable
rules of neurophysiology actually vary little from
person to person. In other words, the minimum amount
of sleep one individual’s body requires to rest
neuronal activity compared to another individual is
not as large as we might see in practice. And, since
auditory rehabilitation involves a process of neural
“rewiring”, lack of sleep only slows or prevents
such activity.
Today, there appears to be a societal
underestimation of the need for a specified amount
of quality sleep in the maintenance of good health
and longevity, personal preferences or perceptions
notwithstanding. This brings our discussion to a
review of possible deleterious effects of sleep
deprivation upon one’s communication and cognitive
ability. In doing so, we will frame the discussion
primarily within the auditory rehabilitative
framework, for suffice to say here that sleep
deprivation is the enemy of effective auditory
rehabilitation.
Brain Neuroplasticity Requires Sleep For Maintenance
& Repair
Today, we know from conclusive research on brain
neuroplasticity that there is actually a
physiological “rewiring” process required for one to
adapt to a new acoustic format (i.e., new hearing
aids). The time required for the rewiring process
varies from individual to individual, but is
generally a period of about 90-120 days for
post-linguistic hearing aid users and up to 2 years
for pre- and peri-linguistic cochlear implant users.
Much depends upon when the hearing loss occurred,
and possible distortions from subsequent yet
misapplied amplification. So, that even an
experienced hearing aid user changing to a new
amplification strategy may require that same 90-120
days to adapt to a new hearing program.
An important point relevant to our discussion here
is that while “learning” occurs during mostly during
waking hours of use, the actual permanent “rewiring”
takes place while the neurons of the brain are at
rest. When neurons do not receive the requisite
amount of rest, they simply fatigue and fail to make
the expected changes.
Another related point is that as hearing ability
declines, whole sections of neurons in the auditory
cortex become “reassigned” to other tasks (some may
simply lay dormant, however). Those other tasks may
be in producing the bothersome tinnitus (ringing in
the ears, occurring most predominantly at the
frequencies being lost over time, in cases of
cochlear-based tinnitus). Hence, the author and
colleagues have long noted that as hearing declines,
and subsequent amplification fails to “cover” its
range, that the tinnitus continues to get louder and
louder to the sufferer. On the other hand, the
greatest relief seems to be found when wide range
amplification (with an F2 of 8KHz or above)
reactivates cortical areas of the brain with
restoration of high frequency stimulation over time.
One popular therapy used for this today is called
“Tinnitus Retraining Therapy” (TRT) by Drs.
Jastreboff and Hazell. At DigiCare Hearing Research
& Rehabilitation we utilize three basic circuit
strategies to achieve optimum benefit:
1) 100Hz-8,000Hz,
2) 50-10,000 Hz,
3) 50-16,000Hz.
It just so happens that patients also enjoy superior
spatial separation, improved speech in noise, less
required gain-to-comfort level and better speech
discrimination ability in these formats. But if the
needed sleep is not realized, “habituation” of the
“reassigned” cortical territory and, ultimately,
auditory rehabilitation may simply fail to occur.
Hence, adequate and quality sleep contribute to the
rehabilitative process.
Optimum Language Processing Requires a Rested
Neurological System
Sleep deprivation, in the context of language
comprehension, would show up in two ways:
1) Reduced RECEPTIVE (heard, understood)
communication, and
2) Reduced EXPESSIVE (spoken) communication
Without adequate sleep, the brain tends to go into a
state similar to that of dyslexia, where rapid
speech sounds faster than, let’s say 200
milliseconds, are not perceived (understood) by the
listener. This level of performance would
significantly lower both sentence recognition scores
and monosyllabic speech discrimination. How many
times have both patients and professionals become
frustrated in trying to adjust hearing aid circuits
to overcome this kind of problem? A rested mind is
simply requisite for optimum speech understanding.
(The reader should also keep in mind that certain
psychotropic drugs could also induce a similar
“dyslexic” state at the receptive level of hearing.
Expressive communication, similarly, is markedly
affected by sleep deprivation, but from a motor
command point of view. In this case, slurred,
stuttered, and/or repetitive speech is produced,
with the as well as higher brain functions, such as
judgment, logic, and impulse control (in the limbic
system). Add deterioration of visual/auditory
association, and finally depression occurs.
Speaking of the addition of the side effects of some
psychotropic medication to a sleep deprivation
problem, it is important to note that without
auditory remediation in cases where hearing
impairment exists, it is almost certain that
diagnoses of Alzheimer’s, Parkinson’s, and Bipolar
will be over-diagnoses. Without auditory
rehabilitation intervention in cases where hearing
loss exists, the prognostic outlook is indeed bleak.
Discussion
Some people think they can train their bodies to go
without the required amount of sleep, but something
they cannot do is regenerate the body and brain in
less time than is required. In fact, attempting to
do so only adds to stress levels, increasing the
need for even more sleep time. Behavior, especially
lack of impulse control and depression, changes with
chronic sleep deprivation. The “quiet readiness” of
the cerebral cortex, our 24-hour radar system tied
to audition particularly is disrupted, and plunges
the readiness state to the lower brain level of the
Amygdala where fear, anger, and anxiety are
subconsciously incited.
Mathematics problem solving and abstract logic are
impaired at the parietal lobes of the left
hemisphere in sleep-deprived individuals. Likewise,
a tiny portion of the spatial locating memory in the
right hemisphere can cause disorientation in finding
one’s way around otherwise familiar territory. Sleep
deprived individuals especially have difficulty
coping with emergency situations where fast reaction
times are crucial. Complexities in life in general
become a quagmire of confusion, while short periods
of “micro-sleep” force its way onto sufferers,
causing more accidents and costly mistakes.
The immune system weakened in sleep deprivation, and
white blood cell activity decreases. Growth and
other needed hormones begin shutting down, the
ability to metabolize sugar declines, causing sugar
to turn to fat. The ultimate affect of chronic sleep
deprivation is early death in all cases.
Sleep deprivation is a serious issue that should be
considered in cases of auditory rehabilitation. Its
presence should be notated in case histories, and
appropriate counseling and/or referral be made.
For more information on sleep deprivation and its
possible effects upon your communicative
rehabilitative progress, “contact us” at
www.digicare.org. |
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