THE NEUROLOGICAL DIAGNOSIS OF ANXIETY
Part 2
These techniques depend on the fact that abnormal brain tissue (e.g., a tumor, damaged or dead neurons or scar tissue) is different from normal tissue. Electrical differences are detected by the electroencephalogram (EEG), which records electrical events occurring in the brain from
wires taped to the surface of the head and scalp.
This technique can often
record the electrical changes that occur in particular parts of the brain during
epileptic seizures, as well as other electrical changes in abnormal tissue.
Since abnormal tissue absorbs X rays to a different degree than bone or
normal brain tissue, X rays are also used to detect abnormality. From a
series of X rays of the brain taken at different angles, a three-dimensional
representation of the brain can be constructed and abnormal tissue within
the brain can be located. This technique is known as
computer-assisted tomography, or the CAT scan.
More recently, techniques have been developed to measure, from the
outside, the rate of metabolism of different parts of the brain. Abnormal tissue
is usually abnormal in rate of metabolism. In one procedure, a radioactive
substance is injected, and the rate at which it is taken up by neurons in
different areas is measured by sensitive devices surrounding the head. With
the aid of computers, a three-dimensional representation of the metabolic
rate in different parts of the brain is produced (the PET scan). These and
other techniques are becoming much more sophisticated, making it more
and more likely that damage can be located and assessed.
It is not always possible to assess the precise location and nature of damage,
and hence to determine the most appropriate treatment. In such cases,
it may be necessary, if the costs of inaction are serious enough, to examine
the brain directly. Exploratory neurosurgery, often leading directly into explicit
surgical intervention to deal with the problem, is then called for. We
will discuss this issue when we consider treatment later.
We illustrate the process of neurological diagnosis with one Case history:
This fifty-five-year-old, right-handed ... housewife ... while working in her
garden at 10:00 A.M. on the day of admission suddenly developed a weakness of
her right side and was unable to speak. Apparently, the right-sided weakness
mainly affected her face and arm since she was still able to walk. Neurological examination
revealed the following: The patient was alert. She had no spontaneous
speech and could not use speech to answer questions and could not even use yes or
no answers. She could not repeat words. The patient was, however, able to indicate
answers to questions by nodding or shaking her head if questions were posed
in a multiple-choice situation. In this manner, it was possible to determine that
she was grossly oriented for time, place and person.
The patient was able to carry
out spoken commands and simple written commands ... Strength of voluntary movement:
there was a marked deficit in the right upper extremity (arm). There was a minor degree
of weakness involving the right lower extremity (leg). Sensation appeared normal.
Brain X rays and EEGs showed no abnormality. [This was in 1969, when the more modern,
computer-enhanced techniques were not generally available.] The patient showed
recovery over the following days. A significant amount of strength returned to the
right hand within twenty-four hours, and by forty-eight hours, she could speak single words,
but there was still no spontaneous speech. Some weeks later, she still had an expressive problem: her speech was slow and labored and included anxiety. (Curtis, Jacobson, and Marcus, 2006, p. 526-28)
The above pattern of symptoms clearly suggests damage to the left hemisphere,
since this is the hemisphere that contains speech centers in almost all
right-handers. The weakness of the right side of the body suggests left-hemisphere
damage, because of contralateral control. The greater weakness in the
arm than the leg makes sense, because the areas innervating the arm are
closer to the areas controlling speech than are the areas controlling the leg.
The fact that all of the symptoms are in action (as opposed to sensation),
suggests a forward location of the lesion, as does the fact that the language
problem is in expression, rather than in comprehension of speech. Since the
most striking and long-lasting symptom is the speech disturbance, it is reasonable
to presume that the focus of damage is Broca's area in the left frontal
lobe, since this is the center for speech production. The patient has an expressive
(Broca's) aphasia (see next section), unconfirmed in this case by
direct measurements on the nervous system. The source of the damage,
given the sudden onset, is almost certainly a blockage of a blood vessel feeding
this area, that is, a stroke.
For the Anxiety Treatment I recommend click this link:
http://theliberatormethod.com
wires taped to the surface of the head and scalp.
This technique can often
record the electrical changes that occur in particular parts of the brain during
epileptic seizures, as well as other electrical changes in abnormal tissue.
Since abnormal tissue absorbs X rays to a different degree than bone or
normal brain tissue, X rays are also used to detect abnormality. From a
series of X rays of the brain taken at different angles, a three-dimensional
representation of the brain can be constructed and abnormal tissue within
the brain can be located. This technique is known as
computer-assisted tomography, or the CAT scan.
More recently, techniques have been developed to measure, from the
outside, the rate of metabolism of different parts of the brain. Abnormal tissue
is usually abnormal in rate of metabolism. In one procedure, a radioactive
substance is injected, and the rate at which it is taken up by neurons in
different areas is measured by sensitive devices surrounding the head. With
the aid of computers, a three-dimensional representation of the metabolic
rate in different parts of the brain is produced (the PET scan). These and
other techniques are becoming much more sophisticated, making it more
and more likely that damage can be located and assessed.
It is not always possible to assess the precise location and nature of damage,
and hence to determine the most appropriate treatment. In such cases,
it may be necessary, if the costs of inaction are serious enough, to examine
the brain directly. Exploratory neurosurgery, often leading directly into explicit
surgical intervention to deal with the problem, is then called for. We
will discuss this issue when we consider treatment later.
We illustrate the process of neurological diagnosis with one Case history:
This fifty-five-year-old, right-handed ... housewife ... while working in her
garden at 10:00 A.M. on the day of admission suddenly developed a weakness of
her right side and was unable to speak. Apparently, the right-sided weakness
mainly affected her face and arm since she was still able to walk. Neurological examination
revealed the following: The patient was alert. She had no spontaneous
speech and could not use speech to answer questions and could not even use yes or
no answers. She could not repeat words. The patient was, however, able to indicate
answers to questions by nodding or shaking her head if questions were posed
in a multiple-choice situation. In this manner, it was possible to determine that
she was grossly oriented for time, place and person.
The patient was able to carry
out spoken commands and simple written commands ... Strength of voluntary movement:
there was a marked deficit in the right upper extremity (arm). There was a minor degree
of weakness involving the right lower extremity (leg). Sensation appeared normal.
Brain X rays and EEGs showed no abnormality. [This was in 1969, when the more modern,
computer-enhanced techniques were not generally available.] The patient showed
recovery over the following days. A significant amount of strength returned to the
right hand within twenty-four hours, and by forty-eight hours, she could speak single words,
but there was still no spontaneous speech. Some weeks later, she still had an expressive problem: her speech was slow and labored and included anxiety. (Curtis, Jacobson, and Marcus, 2006, p. 526-28)
The above pattern of symptoms clearly suggests damage to the left hemisphere,
since this is the hemisphere that contains speech centers in almost all
right-handers. The weakness of the right side of the body suggests left-hemisphere
damage, because of contralateral control. The greater weakness in the
arm than the leg makes sense, because the areas innervating the arm are
closer to the areas controlling speech than are the areas controlling the leg.
The fact that all of the symptoms are in action (as opposed to sensation),
suggests a forward location of the lesion, as does the fact that the language
problem is in expression, rather than in comprehension of speech. Since the
most striking and long-lasting symptom is the speech disturbance, it is reasonable
to presume that the focus of damage is Broca's area in the left frontal
lobe, since this is the center for speech production. The patient has an expressive
(Broca's) aphasia (see next section), unconfirmed in this case by
direct measurements on the nervous system. The source of the damage,
given the sudden onset, is almost certainly a blockage of a blood vessel feeding
this area, that is, a stroke.
For the Anxiety Treatment I recommend click this link:
http://theliberatormethod.com