Amnestic disorders may be self-reported, if the patient has retained insight into his or her memory problems. More often, however, the disorder is diagnosed because a friend, relative, employer, or acquaintance of the patient has become concerned about the memory loss or recognizes that the patient is confabulating, and takes the patient to a doctor for evaluation. Patients who are disoriented, or whose amnesia is associated with head trauma or substance abuse, may be taken to a hospital emergency room.
The doctor will first examine the patient for signs or symptoms of traumatic injury, substance abuse, or a general medical condition. He or she may order imaging studies to identify specific areas of brain injury, or laboratory tests of blood and urine samples to determine exposure to environmental toxins or recent consumption of alcohol or drugs of abuse. If general medical condi- m tions and substance abuse are ruled out, the doctor may e administer a brief test of the patient's cognitive status, i such as the mini-mental state examination or MMSE. d The MMSE is often used to evaluate a patient for so dementia, which is characterized by several distur- e bances in cognitive functioning (speech problems, prob- s lems in recognizing a person's face, etc.) that are not present in amnestic disorders. The doctor may also test the patient's ability to repeat a string of numbers (the so-called digit span test) in order to rule out delirium. Patients with an amnestic disorder can usually pay attention well enough to repeat a sequence of numbers whereas patients with delirium have difficulty focusing or shifting their attention. In some cases the patient may also be examined by a neurologist (a doctor who specializes in disorders of the central nervous system)
If there is no evidence of a medical condition or substance use that would explain the patient's memory problems, the doctor may test the patient's memory several times in order to rule out malingering or a factitious disorder. Patients who are faking the symptoms of an amnestic disorder will usually give inconsistent answers to memory tests if they are tested more than once.
DSM-IV-TR specifies three general categories of amnestic disorders. These are: amnestic disorder due to a general medical condition, substance-induced persisting amnestic disorder, and amnestic disorder not otherwise specified. The basic criterion for diagnosing an amnestic disorder is the development of problems remembering information or events that the patient previously knew, or inability to learn new information or remember new events. In addition, the memory disturbance must be sufficiently severe to affect the patient's social and occupational functioning, and to represent a noticeable decline from the patient's previous level of functioning. DSM-IV-TR also specifies that the memory problems cannot occur only during delirium, dementia, substance use or withdrawal.
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