Chapter                  title                                                                              Page No

1.                                  INTRODUCTION                                                              1                                               1.1 BRAIN

FUNCTIONS OF BRAIN                                                     

2.                                 BRAIN

                                        2.1 DEFINITION                                                                       

                                         2.2 PURPOSE                                                                             10

                                         2.3 USES                                                                             

3.                                 LITERATURE

4.                                DEEP BRAIN

                                        4.1 COMPONENTS                                                                  

                                        4.2 APPLICATIONS                                                                

5.                              COCHLEAR IMPLANTS    


SURGICAL PROCEDURE                                        26



                                      5.5 COST                                                                           


6.                                 CONCLUSION                                                                    29

                                    REFERENCES                                                                    30Chapter


In the previous Chapter, the brain
and its function were discussed briefly.

In this chapter, the definition of brain scions, types
of brain implants and their uses are discussed.

Definition of Brain Implants

Brain implants, often referred to as neural implants, are high-tech devices
that connect directly to a biological subject’s brain – usually placed on
the surface of the brain, or attached to the brain’s cortex.












                                Fig 2.1 Schematic of the “Utah”
Electrode Array


 A common purpose of
modern brain implants and the focus of much current research is establishing
a biomedical prosthesis
circumventing areas in the brain that have become dysfunctional after a stroke or other head
injuries.1 This includes sensory substitution, e.g., in vision. Other brain implants are used in
animal experiments simply to record brain activity for scientific reasons. Some
brain implants involve creating interfaces between neural systems and computer chips. This work is part of a
wider research field called brain-computer interfaces. 

implants such as deep brain stimulation and Vagus nerve stimulation are increasingly
becoming routine for patients with Parkinson’s disease and clinical depressionrespectively, proving
themselves a boon for people with diseases which were previously regarded as


implants electrically stimulate, block or record (or both record and
stimulate simultaneously) signals from single neurons or groups of neurons (biological
neural networks) in
the brain”. The blocking technique is called intra-abdominal vagal
blocking. This can only be done where the functional associations of these
neurons are approximately known. Because of the complexity of neural processing
and the lack of access to action potential related signals using neuroimaging techniques, “The application of
brain implants has been seriously limited until recent advances in
neurophysiology and computer processing power”

2. 3

?  For 
mind control

?  For 

?  For 

?  For 

?  For parkinson’s

?  For hearing

?  For vision


Chapter 3


1870, Eduard Hitzig and Gustav Fritsch confirmed
that electrical stimulation of the brains of dogs could produce
movements. “Robert
Bartholow showed
the same to be true for humans in 1874. By the start of the 20th century, Fedor
Krause began to systematically map human brain areas, using patients that had experienced brain surgery1”.

research was conducted in the 1950s. Robert
G. Heath tested
with aggressive mental patients, aiming to influence his subjects’ moods through
electrical stimulation.”

University physiologist Jose Delgado demonstrated
limited control of animal and human subjects’ behaviours using electronic
stimulation. He devised the stimoceiver or transdermal
stimulator, a device rooted in the brain to transmit electrical impulses
that modify basic behaviours such as aggression or sensations of pleasure.

“Delgado was later to
write a popular book on mind control, called Physical Control of the Mind, where he stated:
“the feasibility of remote control of goings-on in several species of
animals has been demonstrated. The ultimate objective of this research is to
provide an understanding of the mechanisms involved in the directional control
of animals and to provide practical systems suitable for human
application.”Chapter 4

Deep Brain Simulation


“Deep brain stimulation (DBS)
is a neurosurgical procedure
involving the imbedding of a medical device called a Neurostimulators(sometimes
referred to as a ‘brain pacemaker’), which sends electrical instincts, through
implanted electrodes,
to specific targets in the brain (brain nuclei) for
the treatment of crusade and neuropsychiatric disorders”. DBS in select brain
regions has provided therapeutic benefits for otherwise-treatment-resistant
disorders such as Parkinson’s
disease, essential tremor, dystonia, chronic pain, major
depression and obsessive–compulsive
disorder (OCD). Despite the long history of
DBS, its underlying principles and mechanisms are still not clear.DBS
directly changes brain activity in a controlled manner, its effects are
reversible (unlike those of lesioning techniques), and it is one of only a few
neurosurgical methods that allow blinded studies.

“The Food
and Drug Administration (FDA) approved DBS as
a treatment for essential tremor and Parkinson’s
disease in 1997,dystonia in
2003, and OCD in 2009. DBS is also used in research studies to
treat chronic pain, PTSD,and
has been used to treat various affective disorders, including major
depression; none of these
applications of DBS have yet been FDA-approved. While DBS has proven to be
effective for some patients, potential for serious complions and side effects exists”.

The deep brain stimulation system consists of
three components: the implanted pulse generator (IPG), the lead, and an
extension./ The IPG is a battery-powered
neurostimulator encased in a titanium housing, which sends electrical pulses to
the brain that interferes with neural activity at
the target site. The lead is a coiled wire insulated in polyurethane with
four platinum-iridium electrodes
and is placed in one or two different nuclei of the brain. The lead is
connected to the IPG by an extension, an insulated wire that runs below the
skin, from the head, down the side of the neck, behind the ear to the IPG,
which is placed subcutaneously below the clavicle or,
in some cases, the abdomen. The
IPG can be calibrated by a neurologist, nurse,
or trained technician to
optimize symptom suppression and control side-effects.Chapter

Cochlear Implants

A cochlear implant (CI)
is a surgically rooted electronic device that provides a intellect of sound to
a person who is intensely
deaf or severely hard of hearing in
both ears; as of 2014 they had been used experimentally in some people who had
acquired deafness in one ear after learning how to speak. Cochlear implants
bypass the normal hearing process; they have a sound processor that resides on
the outside of the skin (and generally worn behind the ear) which contains
microphones, electronics, battery, and a coil which transmits a signal to the
implant. The implant has a coil to receive signals, electronics, and an array
of electrodes which is placed into the cochlea,
which stimulate the cochlear nerve.

The method in which the device is implanted
is usually done under general
anesthesia. Menaces of the procedures
include mastoiditis, otitis media (acute
or with effusion), shifting of the implanted device requiring a second
procedure, damage to the facial nerve,
damage to the chorda tympani,
and wound infections. People may experience problems with dizziness and balance
for up to a few months after the procedure; these problems generally resolve,
but for people over 70, they tend not to.

“There is low to moderate quality evidence
that when CIs are implanted in both ears at the sa

1me time, they improve hearing in noisy
places for people with severe loss of hearing. There is some suggestion that
implanting CIs to improve hearing may also improve tinnitus but
there is some risk that it may cause people who never had tinnitus to get it.”

There is argument around the devices; much of
the strongest objection to cochlear implants has come from the Deaf community.
For some in the deaf municipal, cochlear implants are an affront to their culture, which as
some view it, is a minority threatened by the hearing majority.







5.1 parts of the ear



Cochlear implants bypass most of the peripheral
auditory system which receives sound
and converts that sound into whereabouts of stereocilia on hair cells in
the cochlea; “The
movement of the stereocilia causes in influx of potassium ions that
arouses the hair cells cells
to release the neurotransmitter glutamate,
which makes the cochlear nerve send
signals to the brain, which makes the familiarity of
sound. Instead, the devices pick up sound and digitize it, convert that
digitized sound into electrical signals, and transmit those signals to
electrodes embedded in the cochlea.”
The electrodes electrically stimulate the cochlear nerve, triggering
it to send signals to the brain.

There are several systems available, but
generally they have the following components:

one or more microphones
that pick up sound from the environment

a speech processor which
selectively filters sound
to prioritize audible

a transmitter that sends
power and the processed sound signals across the skin to the internal device
by electromagnetic


5.2 The internal part of a cochlear implant
(model Cochlear Freedom 24 RE)

a receiver/stimulator, which receives signals
from the speech workstation and converts them into electric impulses.

an electrode array rooted in the cochlea

    5.2 Surgical procedure

surgical procedure most often used to implant the device is called mastoidectomy with facial recess slant (MFRA). If a person’s
individual anatomy prevents MFRA, other approaches, such as through the suprameatal triangle are used. “A systematic literature review published
in 2016 found that studies comparing the two approaches were generally small,
not randomized, and retrospective so were not useful for making
generalizations; it is not known which approach is innocuous or more effective.

procedure is frequently done under general anesthesia. Risks of the procedures
include mastoiditis, otitis media (acute
or with effusion), shifting of the implanted device requiring a second technique,
damage to the facial nerve, damage to the chorda tympani,
and wound infections.”11

“The rate
of complications is about 12% for minor hitches and 3% for major complications;
major complications include infections, facial paralysis, and device failure.
To dodge the risk of bacterial meningitis, which while low is about thirty times as high compared
to people who don’t undergo CI procedures, the FDA commends vaccination prior
to the procedure. The rate of transient facial nerve palsy is estimated

to be
approximately 1%. Device failure requiring reimplantation is estimated to occur

in 2.5-6%
of the time. Up to one-third of people experience disequilibrium, vertigo, or
vestibular paleness lasting more than 1 week after the technique; in people
under 70 these symptoms commonly resolve over weeks to months, but in people
over 70 the problems tend to persist.”

implants are only appropriate for people who are deaf in both ears; as of 2014
a cochlear implant had” been used experimentally in some people who had assimilated
deafness in one ear after they had learned how to state, and not a soul who
were deaf in one ear from birth; clinical studies as of 2014 had been too small
to draw oversimplifications from.”



A 2011 AHRQ review of the evidence of the
effectiveness of CI in people with bilateral hearing loss – the device’s
primary use – found low to moderate quality data that presented: speech
perception in noisy conditions
was much better for people who had implants in both ears done at the same time,
compared to people who had only one; that no conclusions could be drawn about
changes in speech perception in quiet conditions and health-related
quality-of-life. There was only one good study equaling planting implants in
both ears at the same time, to implanting them sequentially; this study found
that in the sequential approach, the 2nd implantation made no change, or made
things worse.

“A 2012 review found that the ability to
communicate in spoken language was better, the earlier the implantation was
done; it also found that overall, the efficacy of cochlear implants is highly
variable, and that it was not possible to accurately predict which children
will and will not acquire spoken language successfully. ”

A 2015 review, examining whether CI
implantation to treat people with bilateral hearing loss had any effect
on tinnitus, “found
the quality of evidence to be poor, and the results variable: overall total
tinnitus suppression rates varied from 8% to 45% of people who received CI;
decrease of tinnitus was seen in 25% to 72%, of people; for 0% to 36% of the people
there was no change; increase of tinnitus occurred in between 0% to 25% of
patients; and in between 0 – 10% of cases, people who didn’t have tinnitus
before the procedure, got it. ”

5.4 Usage

As of
December 2012, approximately 324,000 cochlear implant devices had been
surgically implanted. In the U.S., roughly 58,000 devices were implanted in
adults and 38,000 in children.

5.5 Cost

In the United States, “the overall cost of getting cochlear implants
was about $100,000 as of 2017.18 Some or all of this may be covered by health
insurance. In the United
Kingdom, the NHS covers cochlear implants in full, as does
Medicare in Australia, and the Department of Health19 in Ireland, Seguridad Social in Spain and Israel, and the Ministry of Health or ACC (depending on the cause of deafness) in New Zealand. According to the US National
Institute on Deafness and Other Communication Disorders, the estimated total cost is $60,000 per person
implanted. ”

A study
by Johns Hopkins University determined that for a three-year-old child
who receives them, cochlear implants can save $30,000 to $50,000 in
special-education costs for elementary and secondary schools as the child is
more likely to be mainstreamed in school and thus use fewer support services
than similarly deaf children.

5.6 Manufacturers

As of 2013,
the three cochlear implant devices approved for use in the U.S. were
manufactured by Cochlear
Limited (Australia),
Advanced Bionics (USA, a division of Sonova) and MED-EL (Austria). In Europe, Africa, Asia, South
America, and Canada, an additional device manufactured by Neurelec (France, a division of William Demant) was available. A device made by Nurotron (China)
was also available in some parts of the world. Each manufacturer has adapted
some of the successful innovations of the other companies to its own devices.
There is no consensus that any one of these implants is superior to the others.
Users of all devices report a wide range of performance after implantation
























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