strates symmetrical brain atrophy that is out of pro-portion for age, with an accompanying hydro-cephalous ex vacuo of the third and lateral ventricles. An EEG shows a diffuse slowing of back-ground activity that is nonspecific. PET/SPECT scans demonstrate hypometabolism and reduced blood flow to the temporal and parietal lobes.
Principles of Management and Prognosis There is no method to stop or reverse the progres-sion of AD. However, cholinesterase inhibitors produce modest transient improvements in mem-ory and cognition and may reduce behavioral out-bursts. Low doses of psychoactive medications may be required to treat patients who have fre-quent outbursts of anger or agitation. Studies are underway to determine if reducing amyloid pro-duction and aggregation or enhancing amyloid removal may offer clinical benefit.
The heart of management lies in a quality care-giver. Family caregivers provide most of the daily care, which can be a 24-hour-a-day undertaking since patients require almost constant supervision.
Ideally, patients should be able to safely wander without becoming lost, have meals provided and supervised, and have domestic needs done by
oth-ers (shopping, bill paying, and keeping doctor’s appointments). Sudden worsening of confusion occurs when the patient is moved to new sur-roundings such as a hospital or nursing home. The family caregiver is at risk of becoming exhausted, depressed, and feeling guilty as the disease relent-lessly worsens. Use of other family members or professional attendants to allow caregivers time for themselves, or even brief respites where the patient is placed in a nursing home setting, may be needed. It is strongly recommended that the spouse have scheduled time away and respite care.
The duration of AD, once diagnosed, is about 3 to 5 years and death usually comes from pneumo-nia and other systemic illnesses.
well as disabilities in communication, sensorimo-tor function, and behavior. Disability is the expres-sion of limitations in individual function in a social context and represents a substantial disad-vantage to the individual.
Limitation in adaptive behavior affects both daily life and the ability to respond to life changes and environmental demands. Examples of concep-tual adaptive skills include language, reading, money concepts, and self-direction. Examples of social adaptive skills include interpersonal con-duct, responsibility, self-esteem, gullibility, naiveté, and following rules and laws. Examples of practi-cal adaptive skills include activities of daily living (eating, dressing, and toileting), functional aspects of daily life (transportation, housekeeping, money management, and taking medication) and occupa-tional skills.
Mental retardation is often classified with respect to severity. Mental retardation that is mild presents with an IQ between 50 and 70; moderate is between 35 and 49, severe between 20 and 34, and profound below 20.
Mental retardation may occur from a wide vari-ety of biomedical, social, behavioral, and educa-tion problems that occur in the prenatal, perinatal, or postnatal periods. Table 11-6 lists risk factors for each time period. Table 11-7 lists the major causes of mental retardation. It is important to understand that some causes of mental retardation are due to progressive degenerative illnesses result-ing in steady worsenresult-ing of the IQ and mental retardation. Other causes are static (such as
peri-natal birth injury) and do not progress as the child grows. However, the manifestations of the mental retardation may evolve as the child fails to gain expected childhood developmental skills.
Appro-CHAPTER 11—Disorders of Higher Cortical Function 121
Table 11-6 Major Risk Factors for Mental Retardation
Time
Period Biomedical Social Behavioral Educational
Prenatal Chromosomal disorders Maternal malnutrition Maternal drug use Parental cognitive Single-gene disorders No access to prenatal Maternal alcohol use disability without
Metabolic disorders care supports
Cerebral dysgenesis Maternal age and illness
Perinatal Prematurity Lack of access to Parental rejection Lack of medical
Birth injury birth care of child or services
Neonatal disorders caretaking
Postnatal Traumatic brain injury Impaired child caregiver Child abuse Delay in medical care Malnutrition Lack of infant stimulation Inadequate safety or diagnosis Meningitis Placement in institution measures Inadequate education
Degenerative disorders Social deprivation services
Impaired parenting
Table 11-7 Common Causes of Mental Retardation
Prenatal
Fetal alcohol syndrome Down’s syndrome Fragile-X syndrome Cerebral dysgenesis Autism (not all cases) Perinatal
Birth injury
Marked prematurity and very low birth weight, especially with periventricular hemorrhage Infant illnesses such as severe sepsis, bacterial
meningitis, and undiagnosed hypothyroidism Postnatal
Head trauma from child abuse (shaken baby syndrome), sports injury, or automobile accident Severe malnutrition such as marasmus or
kwashiorkor
Toxic metabolic disorders such as lead intoxication Severe epilepsy
Childhood degenerative diseases
Infections such as bacterial meningitis, whooping cough, and encephalitis
109-122_Davis11 3/2/05 4:25 PM Page 121
priate treatment of the child with mental retarda-tion requires establishing the etiology and treating the cause, if possible, as well as maximizing the personal support the child requires. Mental retar-dation is often accompanied by physical disabili-ties that also require skilled attention. In children with static mental retardation the IQ may not improve over time, but the function in adaptive skills can and this would be significant in the indi-vidual’s quality of life.
RECOMMENDED READING
Albert ML, Knoefel JE, eds. Clinical Neurology of Aging. New York: Oxford University Press; 1994.
(Covers many neurologic aspects of normal aging.)
Cummings JL, Cole G. Alzheimer’s disease. JAMA 2002;287;2335–2338. (Current review of patho-physiology and treatment.)
Luckasson R, Borthwick-Duffy S, Buntinx WHE, et al. Mental Retardation: Definition, Classifica-tion, and Systems of Support, 10th ed. Washing-ton DC: American Association of Mental Retardation; 2002. (Current overview of mental retardation and available support systems.) Petersen RC. Aging, mild cognitive impairment,
and Alzheimer’s disease. Neurol Clin 2000;18:
789–805. (Nice review of mild cognitive impair-ment and the workup of patients with suspected dementia.)
122 FUNDAMENTALS OF NEUROLOGIC DISEASE 109-122_Davis11 3/2/05 4:25 PM Page 122
Overview
The pyramidal system is the motor/premotor cor-tex and corticospinal tract that governs voluntary movements. The extrapyramidal system refers to several systems whose neurons are largely located in the basal ganglia that oversee nonvoluntary, competing aspects of the motor system. Thus one can conceptualize the basal ganglia and substantia nigra as being organized to facilitate voluntary movements and to inhibit competing movements that interfere with the desired movement. This is accomplished by enabling the brain to produce the desired motor pattern while creating a sur-round inhibition of competing motor movements (Figure 12-1). Constant loss of surround inhibi-tion would result in hypokinetic movements while intermittent or fluctuating changes of sur-round inhibition could result in abnormal hyper-kinetic movements.
Extrapyramidal disorders refer to movement disorders that result from damage or presumed dysfunction of the basal ganglia and their brain-stem and cerebellar connections. Movement dis-orders are characterized by either excessive (hyperkinetic) or reduced (bradykinetic) activity.
Parkinson’s disease is the classic hypokinetic
movement disorder while diseases that express chorea, tremor, myoclonus, and tics represent hyperkinetic movement disorders. Below are common types of dyskinesias seen in many patients.
Chorea
Choreas are sudden, brief, nonrepetitive, nonperi-odic, involuntary jerking movements involving shifting muscles or muscle groups of the arms, hands, legs, tongue, or trunk that cannot be volun-tarily suppressed.
Dystonia
Dystonias are strong, sustained, and slow contrac-tions of muscle groups that cause twisting of a limb or the entire body. The contractions are often painful and may appear disfiguring. The dystonia lasts many seconds to minutes and occasionally hours, producing a dystonic posture.
Athetosis
Athetosis consists of sinuous, writhing, alternating contractions of the arms or legs that can blend with dystonia and chorea.
123