Alzheimer's disease: a comprehensive approach to patient management

Despite advances in our understanding of Alzheimer's disease (AD), the diagnosis is still made from the clinical history and assessment of cognitive function. The physical, neurologic exam, and laboratory testing help you look for any other condition that may be contributing to the dementia. Once the diagnosis is made, your role becomes that of a resource to the patient and family. Drug therapies may be needed to manage AD-related depression, sleep/wake cycle alterations, and aggressive behaviors. Some patients with mild to moderate cognitive deficits may be candidates for tacrine or enrollment in clinical trials of experimental therapies. Community resources, advocacy, and driving safety should be discussed with each patient and his/her family.

A 30-week randomized controlled trial of high-dose tacrine in patients with Alzheimer's disease. The Tacrine Study Group

OBJECTIVE

To evaluate the efficacy and safety of high-dose tacrine hydrochloride over 30 weeks in patients with probable Alzheimer's disease.

DESIGN

A 30-week randomized, double-blind, placebo-controlled, parallel-group trial.

SETTING

Outpatients at 33 US centers.

PATIENTS

Men and women at least 50 years of age with mild to moderate Alzheimer's disease and otherwise in good health.

INTERVENTIONS

Group 1 received placebo; group 2 received 40 mg/d of tacrine for 6 weeks, then 80 mg/d for 24 weeks; groups 3 and 4 received 40 mg/d of tacrine for 6 weeks, 80 mg/d for 6 weeks, and 120 mg/d for 6 weeks. Group 3 remained on a dosage of 120 mg/d for a total of 18 weeks; after 6 weeks at 120 mg/d, group 4 titrated to 160 mg/d for the last 12 weeks.

PRIMARY OUTCOME MEASURES

Clinician Interview-Based Impression (CIBI), Alzheimer's Disease Assessment Scale--Cognitive subscale (ADAS-Cog), and Final Comprehensive Consensus Assessment (FCCA).

RESULTS

A total of 663 patients entered the study; 653 patients were included in an intent-to-treat (ITT) analysis; 263 had evaluable data at 30 weeks. The results of the ITT analysis revealed significant (P < or = .05) dose-response trends and between-group comparisons on CIBI and ADAS-Cog. In evaluable patients, significant dose-response trends were observed for all three primary measures (P < or = .001). Significant differences in favor of 160 mg/d of tacrine vs placebo were observed on the CIBI (P < or = .002) and ADAS-Cog and FCCA (P < or = .001), as well as caregiver-global and quality-of-life assessments (P < or = .05). On the CIBI, 23% and 42% of tacrine-treated patients in the ITT and evaluable-patient populations, respectively, were rated improved compared with 17% and 18% of placebo patients, respectively. The primary reasons for withdrawal of tacrine-treated patients were asymptomatic liver transaminase elevations (28%) and gastrointestinal complaints (16%). These adverse events were reversible on discontinuation of treatment, and many patients were able to restart tacrine.

CONCLUSIONS

Tacrine produced statistically significant, dose-related improvements on objective performance-based tests, clinician- and caregiver-rated global evaluations, and measures of quality of life. There was no evidence that the large number of patient withdrawals biased the overall conclusions of the study.

Overview of dementia lacking distinctive histology: pathological designation of a progressive dementia

The group of progressive dementing illnesses that lack distinctive histologic features includes at least four variants: a cortical type, a thalamostriate type, a motor neuronopathy type and a leukogliotic type. While the clinical presentation of some cases is that of anterograde amnesia, progressive aphasia and dysexecutive syndrome are the most common initial symptom complexes. A large number of reported cases are familial, although no abnormal gene has been identified. Pathologically, these illnesses are defined by cortical, hippocampal, striatal, medial thalamic, nigral and motor nuclei cell dropout and astrogliosis. In some cases, white matter gliosis is striking. Identification of specific histological or molecular markers of at least some of these conditions will greatly advance our understanding of these specific conditions as well as dementing illnesses in general.

Cortical biopsy in Alzheimer's disease: Diagnostic accuracy and neurochemical, neuropathological, and cognitive correlations

Neurochemical assessments were performed on biopsy samples taken from the right frontal lobe of patients diagnosed with Alzheimer's disease (AD), before the implantation of a ventricular catheter and pump assembly for the infusion of bethanechol chloride as an experimental therapy. The pathologically diagnosed patients with AD (n = 35; mean age, 67 +/- 1.5 yr) were compared with a group of samples from normal age-equivalent autopsied controls (n = 22; mean age, 68 +/- 2 yr) and autopsied AD brains (n = 11; mean age, 73 +/- 2 yr). Samples were assayed for choline acetyltransferase (ChAT), acetylcholinesterase, binding to [3H]quinuclidinyl benzilate as an index of total muscarinic cholinergic binding, and [3H]pirenzepine binding as an index of M1 cholinergic receptor subtype binding. Mean levels of ChAT activity were decreased in the biopsied patients to 36% of age-matched autopsied controls. The loss of ChAT activity correlated significantly with the Mini-Mental State Examination, an index of global cognitive function. Mean ChAT activity in autopsied AD cortex was further decreased compared with controls, indicating continuous decline through the course of the disease. Acetylcholinesterase followed a similar, less dramatic decline. No differences were found in [3H]quinuclidinyl benzilate binding or [3H]pirenzepine binding between biopsied and autopsied controls. Neuritic plaque counts did not correlate with either the Mini-Mental State Examination or ChAT activity in the biopsy specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Ideomotor apraxia in Huntington's disease

The pattern of movement errors in ideomotor apraxia suggests an abnormality in selection and sequencing of component movements. Individuals with Huntington's disease were evaluated prospectively for the presence of apraxia, and aspects of motor and cognitive function were correlated with apraxic errors. Based on a conservative apraxia rating, ideomotor apraxia occurred in three (33%) of nine patients with a mean duration of disease of 10.4 years. Only two (22%) individuals made no apraxic errors, however, and the group as a whole made apraxic errors in 26% of movements. Apraxia was associated with errors in imitation of nonsymbolic movements but not with errors in recognition of gestures. It correlated significantly with duration of disease and with progressive abnormalities of posture but not with other individual aspects of elementary motor or cognitive function. These associations indicate that apraxia in Huntington's disease may be due primarily to involvement of subcortical motor structures rather than cerebral cortex.

Episodic hyperammonemia in adult siblings with hyperornithinemia, hyperammonemia, and homocitrullinuria syndrome

A 39-year-old man and his 42-year-old sister, both vegetarians, had episodic confusion for many years, but their mental function was normal between those episodes. They were recently diagnosed with hyperornithinemia, hyperammonemia, and homocitrullinuria syndrome. Hyperammonemia was documented during an episode of confusion in the male sibling but not in his sister. Both had elevated plasma ornithine, glutamine, and alanine levels and persistently low plasma lysine levels. Homocitrulline was present in their urine, and orotic aciduria and orotidinuria developed in the male sibling following ingestion of allopurinol. Studies on their cultured skin fibroblasts showed deficient metabolism of ornithine, indicating a defect in ornithine transport across the mitochondrial membrane. During therapy with citrulline and phenylbutyrate sodium, plasma ornithine levels increased in both patients, while plasma levels of glutamine and alanine decreased to normal. Since therapy started, their clinical conditions have also improved, and no recurrent neurologic dysfunction has occurred during a follow-up period of 20 months.

Practical approach to managing behavioral problems in dementia patients

Common behavioral problems encountered in dementia patients include agitation, aggressiveness, hallucinations, and wandering. To minimize or prevent these behaviors, the primary care physician may employ pharmacologic and nonpharmacologic treatments. Manipulation of the environment is effective in selected patients, but pharmacotherapy is still often needed. The role of both options in the effective management of elderly dementia patients is reviewed.

Dementia lacking distinctive histologic features: a common non-Alzheimer degenerative dementia

From a series of 460 dementia patients referred to a regional brain bank, 14 (3%) patients had a pathologic diagnosis of primary degeneration of the brain involving multiple sites (frontoparietal cortex, striatum, medial thalamus, substantia nigra, and hypoglossal nucleus), with cell loss and astrocytosis. There were no neuronal inclusions and essentially no senile plaques. This entity, which we have termed "dementia lacking distinctive histology" (DLDH), presented with memory loss and personality changes, and led to death, usually within 2 to 7 years. Dysarthria and dysphagia were prominent in the later phases of the illness in most patients. The psychometric findings of some of the patients were consistent with a "frontal" lobe dementia. A few patients had prominent caudate atrophy on CT as well as neuropathologically. Eight of our patients had positive family histories for neurologic disease, mainly dementia. DLDH, in addition to Pick's disease, is a major member of the frontal-lobe dementia group. In patients under age 70 years, the frontal lobe dementias represent an important diagnostic consideration.

Implicit learning of new verbal associations

Implicit learning of a series of new verbal associations was studied in four experiments. The first two experiments demonstrated that learning of a repeating sequence of verbal stimuli may occur without awareness, but only when the stimulus-response mapping requires an attention-demanding activity: Subjects who were unaware of the sequence learned when instructed to categorize the stimuli, but not when instructed simply to read them. However, in both situations, unaware subjects performed no better than untrained control subjects in expressing their knowledge of the sequence explicitly. In Experiments 3 and 4, subjects showed implicit learning when the task involved either motor responses to verbal stimuli or verbal responses to spatially arranged stimuli. These findings are discussed in terms of the conditions under which implicit learning can be obtained. First, they demonstrate implicit learning of a set of new associations in the verbal domain. Second, the data suggest that attention is important in implicit learning. Finally, the degree of interitem organization that is familiar preexperimentally seems to partially determine the amount of implicit learning.

Intracerebroventricular bethanechol chloride infusion in Alzheimer's disease. Results of a collaborative double-blind study

The use of intracerebroventricular bethanechol chloride infusion in patients with Alzheimer's disease was first reported in 1984. An initial trial in four patients demonstrated the feasibility of this approach for cholinergic drug delivery to the brain, but objective improvement in cognitive function was not documented. A collaborative placebo-controlled double-blind crossover study has now been carried out in 49 patients with biopsy-documented Alzheimer's disease. The results demonstrate a statistical improvement in Mini-Mental State scores and significantly slower performance on Trails A testing during drug infusion. Other neuropsychological test scores were not similarly affected. The degree of improvement was not sufficient to justify further treatment of Alzheimer's disease patients by intracerebroventricular infusion of bethanechol chloride. The drug delivery system used in the study was well tolerated, with two irreversible complications in more than 50,000 patient days.

Differences between patient and family assessments of depression in Alzheimer's disease

A structured interview covering the DSM-III criteria for major depression was adapted for separate use with Alzheimer's disease patients and with their families. Data from 36 patients yielded a depression rate of 13.9%, whereas information from their families indicated that the rate was 50.0%. This disagreement reflected greater family endorsement of patients' loss of interest or pleasure, irritability, fatigue, and feelings of worthlessness. Use of DSM-III-R criteria narrowed but did not eliminate the discrepancy between patients' and families' assessments of the patients' depression. Uniform procedures for gathering and integrating data from the family that are relevant to diagnosis in this group are indicated.

The spectrum of imaging and neuropsychological findings in Pick's disease

To seek improved methods for the diagnosis of Pick's disease, we reviewed imaging studies of four women and two men (ages 48 to 65 years at onset) and psychometric testing of three of them with autopsy or biopsy-proved Pick's. The presence of Pick bodies was required for the diagnosis. Seven patients with biopsy-proved Alzheimer's disease served as a comparison group. In the Pick's patients, CT in five of six showed marked frontal pole or temporal pole atrophy, which clearly differed from the pattern of cerebral atrophy seen in the Alzheimer's patients. Psychometric testing showed performance patterns that tended to differ from those of the Alzheimer's patients in that recent memory was relatively preserved despite marked impairment of executive functions. The distinctive psychometric pattern in the Pick's patients was evanescent, however. Thus, there were imaging and psychometric findings of potential diagnostic value for Pick's disease, but, for different reasons, they were imperfect.

A verbal memory test with high predictive accuracy for dementia of the Alzheimer type

The most common early deficit in patients with Alzheimer's disease (AD) is in recent memory. Distinguishing patients with AD from normal elderly individuals, using currently available memory tests, is limited by their lack of suitability for bedside use or for large-scale screening. We have devised a new memory test, a delayed word recall (DWR) test, that is both brief and efficient. It was designed specifically to maximize the likelihood of poor performance in patients with AD and minimize the likelihood of poor performance in normal elderly subjects. The DWR test uses required elaborative processing of to-be-remembered words and delayed free recall. Fifty-five normal elderly subjects and 28 patients with possible or probable AD were tested. The overall predictive accuracy of the DWR test was 95.2%. In addition, scores on the DWR test in normal subjects were not correlated with education or age. The inclusion of the DWR test in a previously studied cognitive detection battery for AD resulted in a considerable improvement in predictive accuracy.

Implicit learning of new verbal associations

Implicit learning of a series of new verbal associations was studied in four experiments. The first two experiments demonstrated that learning of a repeating sequence of verbal stimuli may occur without awareness, but only when the stimulus-response mapping requires an attention-demanding activity: Subjects who were unaware of the sequence learned when instructed to categorize the stimuli, but not when instructed simply to read them. However, in both situations, unaware subjects performed no better than untrained control subjects in expressing their knowledge of the sequence explicitly. In Experiments 3 and 4, subjects showed implicit learning when the task involved either motor responses to verbal stimuli or verbal responses to spatially arranged stimuli. These findings are discussed in terms of the conditions under which implicit learning can be obtained. First, they demonstrate implicit learning of a set of new associations in the verbal domain. Second, the data suggest that attention is important in implicit learning. Finally, the degree of interitem organization that is familiar preexperimentally seems to partially determine the amount of implicit learning.

Longitudinal study of death and institutionalization in patients with primary degenerative dementia

We studied the outcome of 101 patients with primary degenerative dementia. The patients were outpatients at the time of the initial evaluation, and all had family caregivers. There were substantial differences in mortality and institutionalization between the mild and advanced patients, as defined by scores on mental status examination. Similar differences in those two outcomes were also evident when the patients were stratified by scores on activities of daily living and disruptive behavior assessments. Thus, certain patient characteristics may be of value in predicting risk for institutionalization and death.

Implicit learning in patients with probable Alzheimer's disease

The purpose of the present study was to determine whether patients with probable Alzheimer's disease (AD) were capable of implicit procedural learning. AD patients and elderly control subjects were given a serial visual reaction time task with an embedded repeating sequence. The AD patients responded more slowly than the controls, but many nonetheless showed learning of the repeating sequence. Patients who failed to learn the sequence were similar in age and overall severity of dementia to those who learned, but they scored lower on some tasks of nonverbal reasoning.

Neurochemical dissociation of memory systems

The administration of scopolamine, an anticholinergic drug, reduced the ability to recall and recognize stimuli presented previously--abilities thought to require declarative memory. In contrast, measures of procedural memory were unaffected by scopolamine: performance on a serial reaction time task incorporating a repeating stimulus and response sequence showed no difference in acquisition and retention of the sequence after scopolamine or saline. These results suggest that the cholinergic system is required for declarative but not procedural memory.

The validity of computed tomographic scan findings for the localization of cerebral functions. The relationship between computed tomography and hemiparesis

We studied recovery from hemiparesis in 52 patients who participated in the Hennepin County (Minnesota) Recovery From Aphasia Study. Our intent was to determine the anatomic correlates of recovery from hemiparesis and then to contrast computed tomography (CT)-hemiparesis relationships with CT-aphasia relationships in this same population. Hemiparesis was assessed at one month after onset and again at six months after onset. Computed tomographic scans were obtained five months after onset and analyzed quantitatively for lesion location. The presence or absence of arm paresis was strongly predicted by CT scan findings in the supratentorial corticospinal pathway. However, three of 25 nonparetic patients had lesions in the corticospinal pathway, and one of 22 severely paretic patients lacked an appropriate lesion. This study demonstrated that a small but inherent lack of specificity and sensitivity existed in the predictive power of CT localization of lesions potentially affecting the motor system, suggesting that some caution is necessary in interpreting the lesion-deficit relationships in less well-localized functions, eg, language. Besides considering the lack of precision in localizing with CT, the existence of individual differences both in anatomy and localization of function must be taken into account.

The critical role of Wernicke's area in sentence repetition

The anatomical correlates of persistent deficits in sentence repetition were studied in a group of 32 right-handed patients with fluent aphasia caused by left hemisphere ischemic stroke. Patients whose ability to repeat remained impaired by 6 months after onset almost without exception had damage to Wernicke's area. Furthermore, all patients with damage to Wernicke's area had impaired repetition 6 months after onset. The most consistent lesion correlating with chronic impairment of repetition, therefore, was one destroying parts or all of Wernicke's area. Lesions outside of this area typically resulted in milder impairment of repetition that resolved within a few months. Only 5 patients had no repetition impairment when tested early (1 month after onset). These patients all had lesions anterior to the rolandic fissure, some including Broca's area.

Dementia without Alzheimer pathology

We studied five demented patients who, on neuropathologic examination, had cell loss and Lewy bodies in substantia nigra and locus ceruleus and few Alzheimer-type changes. The nucleus basalis had minimal cell loss in three patients and was not available in two. The lesions in the substantia nigra and locus ceruleus were unlikely to account for the dementia, and other structural or biochemical derangements, probably cortical but possibly subcortical, must also have been present but not visible at the light microscopic level.