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  • Memory Complaints and Depression in a Young Adult: Case Report

    Authors

    George P. Prigatano, PhD
    Heather Caples, PhD

    Division of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona

    Abstract

    Memory complaints are common in depressed patients.  This case report demonstrates that learning and memory can be normal in depressed young adults who report memory difficulties.  Such patients may perform poorly on memory tests if the information is presented only once.  Their performance, however, may reflect difficulties with concentration rather than with retention per se.  Neuropsychological testing may be especially helpful in differentiating psychiatric-based problems from neurologic-based problems in young adults.

    Key Words: depression, memory, neuropsychological tests

    Patients complaining of memory difficulties may be referred for a neuropsychological examination to help establish a diagnosis and the appropriate management.  A common question is whether a patent is depressed and exhibiting related memory difficulties or whether the patient has an impairment compatible with an undiagnosed brain disorder.

    Whether depression negatively influences performance on standardized tests of memory is still debated. Bieliauskas[1] has questioned whether self-reported measures of depression in the elderly correlate with objective measures of memory impairment.  Boone and coworkers[2] noted only mild or subtle weaknesses in visual memory and nonverbal intelligence in “older healthy, unmedicated outpatients with major depression” while verbal memory, verbal intelligence, and language were unaffected.  As the severity of depression increased, however, patients exhibited mild difficulties, primarily in speed of information processing and executive functions.  These problems were unrelated to memory performance.  Reitan and Wolfson[10] also questioned whether any type of emotional disturbance reliably affects performance on neuropsychological tests.  They added the important clinical caveat, however, that “a comprehensive clinical evaluation is needed in each individual case” (p. 17) to determine whether a patient is impaired.

    In clinical practice, four basic clinical scenarios provide information concerning the important questions of if and how depression influences memory performance on neuropsychological tests.  First, do young healthy adults with a history of depression and complaints of memory impairment typically perform poorly on memory tests?  Second, do young adults with a brain disorder, memory complaints, and depression perform worse on memory tests than young adults with a brain disorder who are not depressed?  These questions focus on how a brain disorder may interact with depression to influence performance on memory tests in young adults.

    A third scenario encountered in clinical practice involves the elderly, among whom depression is also common.  Do self-reports of depression in the elderly, medically ill population (e.g., those with multiple systems disease taking multiple medications who report memory difficulties) relate to memory impairment on neuropsychological tests?  Bieliauskas1 has argued no, but there may be clinical instances that suggest otherwise.  Finally, and perhaps most importantly from a neurological perspective, can neuropsychological testing distinguish between elderly, medically ill patients with memory complaints who are depressed and similar individuals who are showing early stages of dementia?

    Considering examples of these scenarios may help answer the questions and provide guidelines for clinical practice and research.  This article focuses on the first clinical scenario and describes the neuropsychological test findings of a young, healthy woman who complained of memory impairment and a history of depression.

    Case Report

    Neurological Examination

    A 39-year-old, right-handed woman who had complained of memory problems and decreased concentration for a year underwent a neurological evaluation.  She reported to her neurologist that she had difficulty following directions at work and forgot names.  She stated that she often forgot entire conversations and had difficulty finding words in the middle of conversations.

    She had a history of Graves’ disease and had received radiation therapy.  At the time of her neurological evaluation, her thyroid function was considered to be within the normal range.  She also had a history of depression, anxiety, sleep disturbances, headaches, and anemia.  She was taking the following medications: 0.125 mg levothyroxine daily, 0.5 mg liothyronine twice daily, birth control pills daily, and Ecotrin daily.  Magnetic resonance imaging obtained about a year before her neuropsychological evaluation was interpreted as normal.

    Two of her sisters had multiple sclerosis.  Neither her parents nor grandparents had a history of dementia.
    The examination uncovered no neurological abnormalities.  The neurologist’s diagnostic impression was memory problems with an unclear etiology.  A neuropsychological examination was requested.

    Neuropsychological Interview

    When interviewed, the patient was cooperative and pleasant.  She recounted the same difficulties with memory and orientation that she had reported in her neurological examination.

    She had completed high school, was in a second marriage, and had two children.  She reported no history of learning disabilities.

    She reported that she went to bed between 9 and 10 PM each night and fell asleep listening to the television.  Typically, she slept a few hours, awakened, and then fell back to sleep.  Her sleep was typically disturbed.  When questioned, she stated that this sleep pattern had begun several years earlier when her first husband had left her. With tears in her eyes, she noted that she needed the radio or television on to feel comforted.  She reported no problems with appetite, smell, or taste.

    When asked to rate her level of difficulty with remembering important things or things that she was motivated to recall on scale from 0 to 10 (0 meaning no difficulties, and 10 meaning a severe problem), she rated herself a 5.  She rated her concentration difficulties a 10, word-finding difficulties an 8, irritability a 10, anxiety a 6, and depression a 4.  No significant others were available to give their perception of her functioning in these dimensions (ratings from relatives are a part of our normal neuropsychological examination).

    Neuropsychological Testing

    On the BNI Screen for Higher Cerebral Functions, the patient’s speech was fluent and had no dysarthric qualities.  She made no paraphasic errors.  Her auditory comprehension, naming, sentence repetition, reading, writing, and spelling were normal.  She was oriented to time and place.  There was no confusion about right-left orientation or constructional dyspraxia.  She could repeat five digits in both forward and reverse order.  She performed visual scanning and pattern-copying tasks without difficulty.  She had slight difficulty with the visual-sequencing test and tears came to her eyes in response to her frustration.  She could recall four of four number-symbol associations and three of three words with distraction.  She had slight difficulty generating affect in her tone of voice but could generate anger upon request.  She could perceive facial affect without difficulty.  Her total score on the BNI Screen was 48 of 50 points (T score=52).  During the examination, the clinician observed subtle problems with concentration and dysphoric mood rather than memory difficulties.

    On the Controlled Word Association Subtest of the Multilingual Aphasia Examination, she generated 30 words over three trials.  This score is in the average range.

    On the Wechsler-Adult Intelligence Scale (3rd ed), her Verbal IQ score was 104 and her Performance IQ score was 94, yielding a Full Scale IQ score of 100.  Her age-adjusted scaled scores were as follows: Information=9, Digit Span=12, Vocabulary=11, Similarities=11, Picture Completion=5, Block Design=9, Digit Symbol-Coding=13, Picture Arrangement=10, and Symbol Search=9.  All scores, except those dealing with visual attention, were in the average range.

    On the Rey Auditory Verbal Learning Test, she recalled six words on Trial 1 followed by eight words on Trial 2.  On Trials 3, 4, and 5, she recalled 10, 12, and 13 words, respectively.  The total number of words recalled was 49.  After brief distraction, she recalled 10 words.  Twenty minutes later she recalled 10 words.  These scores were in the average range for her age and educational background.  Qualitatively, she wanted to give up on this test but was encouraged to persist. With encouragement, she was able to recall one to two words more on each trial.

    On the Brief Visuospatial Memory Test (Revised Form), her recall of visuospatial information produced a T score of 43 on Trial 1, of 55 on Trial 2, and of 57 on Trial 3. Her delayed recall produced a T score of 58 and scores were in the normal range.

    On the Wechsler Memory Scale (Revised Form), her recall of short stories was at the 49th percentile for immediate recall and at the 37th percentile for delayed recall.  Her recall of visuospatial information was at the 27th percentile for immediate recall and at the 12th percentile for delayed recall.  Thus, when information was presented to her only once, her recall was below normal expectations.  When information was presented repetitively, she could learn and retain it.

    On the Halstead Finger-Tapping test, her speed was 40.2 taps/min with the dominant right hand and 40.4 taps/min with the left hand.  The resulting T scores were 41 and 49, respectively.

    On the Patient Competency Rating Scale, she reported no major difficulties in her daily functioning.  She did report mild difficulties with handling finances, keeping appointments on time, starting conversations in groups, and staying involved with work activities when tired or bored.  She noted that it was extremely difficult for her to handle arguments and to accept criticism.  She acknowledged problems adjusting to unexpected changes, getting help when confused, understanding new instructions, controlling her temper, and keeping from being depressed.

    Her profile on the Minnesota Multiphasic Personality Inventory-II was clinically valid.  Her scores were elevated on Scales 2, 3, 7, 8, and 4.  Overall, her profile was indicative of a dysthymic disorder.

    Neuropsychological Outcome

    This woman’s IQ score was normal, and her memory performance was compatible with her IQ levels.  An important feature of her performance was that once she learned information, she could retain it without difficulty.  If, however, information was presented a single time, her performance fell below normal.  During the evaluation she wanted to give up on memory tests prematurely but was able to learn more information with encouragement.  Such qualitative information can help distinguish depression-related memory complaints from a true memory disorder.

    Overall, the diagnostic impression of the patient was that her neuropsychological test findings and memory were normal but that she exhibited a dysthymic disorder.  When this information was shared with the patient, she spontaneously noted that she had stopped taking her antidepressant medication about 1.5 years ago, precisely when her memory complaints initially began.

    Discussion

    This case addresses the question of whether young depressed patients with memory complaints perform poorly on memory tests.  In this case, the answer was no.  This case suggests that such patients may do poorly on memory tests if information is presented a single time.  Once information is learned, however, they may retain it.
    This case also illustrates the tendency among young depressed individuals to give up when performing tests that frustrate them.  It is crucial for examiners to encourage them to perform to maximum capacity. Problems with energy level and motivation often result in poor performances on memory tests independent of an organic disorder.

    The question arises whether this patient’s Graves’ disease could account for her memory difficulties and psychiatric status.  Graves’ disease is associated with a variety of psychiatric difficulties including depression, anxiety, irritability, and problems with planning and thought organization.[4,7,11]  This disorder could have contributed to the patient’s symptom picture.  She exhibited signs of depression and anxiety, but they most likely reflected a dysthymic disorder.  Although patients with Graves’ disease may report cognitive problems, there is no consistent evidence demonstrating ongoing cognitive disturbances in this subgroup.

    A secondary question is whether the patient may be showing early signs of multiple sclerosis.  Her complaints were not consistent with the typical early sequelae of this disease.  Such individuals often have problems acquiring and retaining information once learned.[8,9]  Our patient did not exhibit this pattern.

    Neuroimaging Studies and Major Depression

    The present case illustrates normal neuropsychological functioning in an individual with a dysthymic disorder who would not be considered to have a major depressive disorder.  To our knowledge, no neuroimaging studies have described potential blood flow patterns in this population. However, the literature on cerebral blood flow abnormalities in individuals with major depressive disorders is growing.

    Kennedy and coworkers[5] reported changes in regional brain glucose metabolism in patients with major depression who were treated with paroxetine. Glucose metabolism, particularly in the prefrontal cortex, increased as a result of treatment.  Interestingly, glucose metabolism in the right hippocampal area and parahippocampal regions decreased.  Although their findings were not related to performance on neuropsychological tests, they re-emphasized the importance of frontal limbic connections in the expression of emotional disturbances, including depression.  Liotti and colleagues[6] have argued that decreased blood flow in the orbitofrontal region may be related to unipolar depression.  Bremmer et al.[3] also reported reduced volume of blood flow in the orbitofrontal cortex in individuals with a history of major depression.  From a neuropsychological perspective, these studies have considerable importance.  Clinicians often see patients with orbitofrontal brain injuries who have difficulty modulating or controlling their emotions.  These patients may be depressed and suicidal.

    Collectively, these findings suggest that depression may affect anterior brain structures involved with the frontal-limbic system.  Such individuals would be expected to have problems with attention, concentration, and problem-solving but not necessarily with memory per se.  Individuals with these types of disturbances may be especially susceptible to distraction (i.e., they may have a hard time registering information presented once).  Clinically, our patient’s profile is consistent with these observations. She had subtle problems remembering information presented once but did not show a true problem with the initial acquisition and later recall of information once learned.  Future studies using neuroimaging to evaluate dysthymic patients may provide greater insight into why these patients complain of memory disorders but show no objective impairments on memory testing.

    References

    1. Bieliauskas LA: Depressed or not depressed? That is the question.  J Clin Exp Neuropsychol 15:119-134, 1993
    2. Boone KB, Lesser IM, Miller BL, et al: Cognitive functioning in older depressed outpatients: Relationship of presence and severity of depression to neuropsychological test scores.  Neuropsychology  9:390-398, 1995
    3. Bremmer JD, Vythilingam M, Vermetten E, et al: Reduced volume of orbitofrontal cortex in major depression.  Biol Psychiatry 51:273-279, 2002
    4. Fahrenfort JJ, Wilterdink AM, van der Veen EA: Long-term residual complaints and psychosocial sequelae after remission of hyperthyroidism.  Psychoneuroendocrinology 25:201-211, 2000
    5. Kennedy SH, Evans KR, Kruger S, et al: Changes in regional brain glucose metabolism measured with positron emission tomography after paroxetine treatment of major depression.  Am J Psychiatry 158:899-905, 2001
    6. Liotti M, Mayberg H, McGinnis S, et al: Unmasking disease-specific cerebral blood flow abnormalities: Mood challenge in patients with remitted unipolar depression.  Am J Psychiatry 159:1830-1840, 2002
    7. Placidi GP, Boldrini M, Patronelli A, et al: Prevalence of psychiatric disorders in thyroid diseased patients.  Neuropsychobiology 38:222-225, 1998
    8. Rao SM: Neuropsychology of multiple sclerosis: A critical review.  J Clin Exp Neuropsychol 8:503-542, 1986
    9. Rao SM: Neurobehavioral Aspects of Multiple Sclerosis. New York: Oxford University, 1990
    10. Reitan RM, Wolfson D: Emotional disturbances and their interaction with neuropsychological deficits.  Neuropsychol Rev 7:3-17, 1997
    11. Stern RA, Robinson B, Thorner AR, et al: A survey of neuropsychiatric complaints in patients with Grave’s disease.  J Neuropsychiatry Clin Neurosci 8:181-185, 1996

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