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Electric Field Effects in the Brain?

KP-PC k.p.collins at worldnet.att.net%remove%
Mon Apr 28 16:25:07 EST 2003


Here are a couple of more abstracts, with brief discussion:

--------- 2nd abstract:

Annu Rev Biomed Eng 2003 Apr 16; [epub ahead of print] Related
Articles, Links

Cochlear Implants: Some Likely Next Steps.

Wilson BS, Lawson DT, Muller JM, Tyler RS, Kiefer J.

Research Triangle Institute, Research Triangle Park, NC 27709.

The history of cochlear implants is marked by large improvements in
performance, especially over the past two decades and especially due
to the development of ever-better processing strategies. Although the
progress to date has been substantial, present devices still do not
restore normal speech reception, even for top performers and
particularly for listening to speech in competition with noise or
other talkers. In addition, a wide range of outcomes persists, with
some patients receiving little benefit using the same devices that
support high levels of speech reception for others. The purpose of
this review is to describe some likely possibilities for further
improvement, including (a) combined electric and acoustic stimulation
of the auditory system for patients with significant residual
hearing, (b) use of bilateral implants, (c) a closer replication with
implants of the processing steps in the normal cochlea, and (d)
applications of knowledge about factors that are correlated with
outcomes to help patients presently at the low end of the performance
scale. Expected online publication date for the Annual Review of
Biomedical Engineering Volume 5 is July 11, 2003. Please see
http://www.annualreviews.org/catalog/pub_dates.asp for revised
estimates.

Bilateral is an absolute necessity with respect to auditory implants.
Simple discernment of auditory directionality is greatly augmented by
bilateral activation in audition. In absence of bilateral activation,
I expect to see instances of 'sweeping head motions' that are
calculated to assist in sound localization. Bilateral implants would
eliminate [or reduce] such 'extraneous' behavior.

The difficulty with respect to background noise separation definitely
stems from an absence of bilateral activation, because the
auditory-input-deficient 'side' of the brain will be 'taken over' by
other, not necessarily auditory-remnant-involved, activation - so
inserting only one choclear implant introduces an artificial
assymetry that results in activation destructively competing with
respect to global TD E/I-minimization.

I expect that the 'background noise' separation difficulties
correlate to "supersystem configuration" [AoK, Ap5] difficulties that
derive in such destructive competition with respect to TD
E/I-minimization in uni-lateral choclear implants.

What's happening is that. because of this destructive competition
with respect to TD E/I-minimization is that the uni-lateral implant
is imposing a 'random' TD E/I condition within the global TD
E/I-minimization dynamics.

This is exactly the sort of condition that I've addressed in my
larger discussions with respect to 'implants'. If an implant
interferes with global TD E/I-minimization dynamics, over the Life
'time' of the implant subject, the implant will introduce
=generalized= information-processing deficits.

With respect to this, even early-in-the-exploration implants should
all be bilateral.

No 'short-cuts' when there's a Life hanging in the balance. If
folks're going to do this stuff, they should always do it in the best
possible way.

That uni-lateral auditory implants are not the best way is flat-out
obvious [Before reading this abstract, I was unaware that uni-lateral
implants were allowed.]

--------- 3rd abstract:

PMID: 12704085 [PubMed - as supplied by publisher]

Int J Pediatr Otorhinolaryngol 2003 May;67(5):479-95 Related
Articles, Links


Speech perception skills of deaf infants following cochlear
implantation: a first report.

Houston DM, Pisoni DB, Kirk KI, Ying EA, Miyamoto RT.

Department of Otolaryngology, Head and Neck Surgery, Indiana
University School of Medicine, 699 West Drive, 46202, Indianapolis,
IN, USA

OBJECTIVE: We adapted a behavioral procedure that has been used
extensively with normal-hearing (NH) infants, the visual habituation
(VH) procedure, to assess deaf infants' discrimination and attention
to speech. METHODS: Twenty-four NH 6-month-olds, 24 NH 9-month-olds,
and 16 deaf infants at various ages before and following cochlear
implantation (CI) were tested in a sound booth on their caregiver's
lap in front of a TV monitor. During the habituation phase, each
infant was presented with a repeating speech sound (e.g. 'hop hop
hop') paired with a visual display of a checkerboard pattern on half
of the trials ('sound trials') and only the visual display on the
other half ('silent trials'). When the infant's looking time
decreased and reached a habituation criterion, a test phase began.
This consisted of two trials: an 'old trial' that was identical to
the 'sound trials' and a 'novel trial' that consisted of a different
repeating speech sound (e.g. 'ahhh') paired with the same
checkerboard pattern. RESULTS: During the habituation phase, NH
infants looked significantly longer during the sound trials than
during the silent trials. However, deaf infants who had received
cochlear implants (CIs) displayed a much weaker preference for the
sound trials. On the other hand, both NH infants and deaf infants
with CIs attended significantly longer to the visual display during
the novel trial than during the old trial, suggesting that they were
able to discriminate the speech patterns. Before receiving CIs, deaf
infants did not show any preferences. CONCLUSIONS: Taken together,
the findings suggest that deaf infants who receive CIs are able to
detect and discriminate some speech patterns. However, their overall
attention to speech sounds may be less than NH infants'. Attention to
speech may impact other aspects of speech perception and spoken
language development, such as segmenting words from fluent speech and
learning novel words. Implications of the effects of early auditory
deprivation and age at CI on speech perception and language
development are discussed.

PMID: 12697350 [PubMed - in process]

I strongly expect that future study will disclose that the 'positive
results' [longer CI looking] derive in the imposed resistance to TD
E/I-minimization that the choclear implants impose within the
Infants' nervous systems.

The Infants are experiencing un-TD E/I-minimizable 'novelty', which
one of the conditions that I was talking about in my prior
discussions.

Think about all that's entailed. Relative novelty is 'normally' a
highly-dynamic 'state' that's trimmed down to the 'nothingness' of
'familiarity' through the functioning of the intermediate 'level'
hippocampal TD E.I-minimization mechanism, which is coupled with
"inverting reward" [AoK, Ap5]. As hippocampal TD E/I-minimization
occurs, "inverting reward" subsides, and this's =crucial= within the
dynamics of 'normal' learning.

If the implants defeat all this by injecting non-TD E/I-minimizable
activation, to the degree that they do, they'll simultaneously impact
general learning dynamics, which'll ramify within all of behavior.

You know. going in-there to 're-engineer' things is a very-serious
undertaking.

It's more of why I 'lament' NDT's understanding being withheld from
folks.

I'm =not= 'against' exploring possibilities, but, Gees Louise! don't
forsake useful understanding and just go in-there to muck-around
willy-nilly.

K. P. Collins

--
"Schmitd! Schmitd! Ve vill build a Shapel!"

"KP-PC" <k.p.collins at worldnet.att.net%remove%> wrote in message
news:Hhgra.129578$ja4.5648761 at bgtnsc05-news.ops.worldnet.att.net...
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