Degenerative Disease. This group of disorders is
characterized by a degeneration of neurons in the
central nervous system. Commondegenerative diseases
include Huntington’s chorea, Parkinson’sdisease,
and Alzheimer’s disease and other dementia.
Alzheimer’s disease is the most common degenera-
tive disease (age of onset is typically 65 years old or
older), followed by Parkinson’s disease (age of onset
50 to 60 years old), and finally, Huntington’s chorea
(age of onset 30 to 50 years old). In all three cases,
there is progressive cerebral degeneration along with
other symptoms in the motor areas. Eventually,
patients in these categories show severe disturbances
in many behavioral areas, including motor, speech,
language, memory, and judgment difficulties. More
and more, neuropsychologists are attempting to
identify and diagnose early stages of diseases like
Alzheimer’s in order to provide treatment that may
have maximal impact on future functioning (Bondi,
Jak, Delano-Wood, Jacobson, Delis, & Salmon,
2008).
Nutritional Deficiencies. Malnutrition can ulti-
mately produce neurological and psychological dis-
orders. They are most often observed in cases of
Korsakoff’s psychosis (resulting from nutritional
problems brought about by poor eating habits com-
mon in longtime alcoholics), pellagra (niacin/vita-
min B 3 deficiency), and beriberi (thiamin/vitamin
B 1 deficiency).
Toxic Disorders. A variety of metals, toxins,
gases, and even plants can be absorbed through
the skin. In some instances, the result is a toxic or
poisonous effect that produces brain damage. A
very common symptom associated with these dis-
orders isdelirium(disruption of consciousness).
Chronic Alcohol Abuse. Chronic exposure to
alcohol often results in tolerance for and depen-
dence on the substance. Tolerance and dependence
appear to have neurological correlates, including,
for example, changes in neurotransmitter sensitivity
and shrinkage in brain tissue.
Several regions of the brain seem especially
vulnerable to damage from chronic exposure to
alcohol (Oscar-Berman & Marinkovic, 2003, 2007;
U.S. Department of Health and Human Services,
2000). We highlight only a few of the most consis-
tent findings here. The limbic system is a network
of structures within the brain associated with mem-
ory formation, emotional regulation, and sensory
integration. Studies of alcoholics have indicated
deficits in these areas of functioning. The dienceph-
alon is a region near the center of the brain that
includes the mammillary bodies of the hypothala-
mus. Studies suggest shrinkage or lesions in these
areas as a result of chronic alcohol exposure, and
memory deficits in alcoholics are consistent with
these findings. Several studies have also reported
findings that suggest alcoholics evidence atrophy
of the cerebral cortex. Finally, damage to the cere-
bellum, responsible for motor coordination, is also
well documented. A history of accidental falls or
automobile accidents may suggest neurological
damage resulting from alcohol abuse/dependence.
Figure 18-2 depicts these brain regions that have
been implicated in studies of the effects of alcohol-
ism on the brain.Consequences and Symptoms
of Neurological Damage
Brain injury or trauma can produce a variety of cog-
nitive and behavioral symptoms. Unfortunately for
the diagnostician, many of these symptoms may also
occur in connection with traditional mental disor-
ders. Moreover, patients’responses to neurological
impairment may give rise to psychological and emo-
tional reactions. For example, an individual with
neurological damage may become depressed over
the inability to manage certain daily tasks. This in
turn can easily obscure the process of differential
diagnosis. These difficulties aside, several common
symptoms associated with neurological damage are
in the list that follows. However, each of these may
occur in every disorder, and there is considerable
variation among patients with the same disorder.- Impaired orientation: inability, for example, to say
who one is, name the day of the week, or
know about one’s surroundings.
520 CHAPTER 18