Epidemiology and Management of Apathy in Patients with Alzheimer??s Disease

Efficacy and safety of neuromodulation for apathy in patients with Alzheimer's disease: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Non-pharmacological interventions, including noninvasive neuromodulation, may alleviate apathy in individuals with Alzheimer's disease. This systematic review and meta-analysis investigated the efficacy and safety of neuromodulation for apathy in elderly patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI).

METHODS

The Cochrane Central Register of Controlled Trials, EMBASE, and PubMed databases were searched for randomized controlled trials (RCTs) of neuromodulation for apathy in AD or MCI. The primary outcome was change in apathy based on the Apathy Evaluation Scale. Secondary outcomes were change in global cognition and trial discontinuation.

RESULTS

The meta-analysis included four RCTs involving 89 patients (aged 65.6-80.5 years) with apathy in AD or MCI. Findings showed no significant improvement in apathy (SMD = 0.57, 95% CI = -0.22-1.36; P = 0.16) or global cognition (SMD = 0.83, 95% CI = -0.11-1.78; P = 0.08) with neuromodulation compared to sham. Subgroup analyses showed significant improvement in apathy with high-frequency rTMS at 120% RMT compared to sham (SMD = 1.36, [95% CI = 0.61-2.12]; P = 0.0004), but not with rTMS at 80% RMT. For global cognition, high-frequency rTMS resulted in significant enhancement (SMD = 1.34 [95% CI = 0.59-2.10]; P = 0.0005), but no notable difference was observed with tDCS compared to sham. There was no significant difference in trial discontinuation in patients with AD or MCI treated with neuromodulation compared to sham.

CONCLUSION

High-frequency rTMS at 120% RMT for four weeks may be efficacious and safe for the treatment of apathy in elderly patients with AD or MCI. High-frequency rTMS may also improve global cognition in these patients. This implies rTMS has potential as an intervention for apathy in AD and MCI. Large well conducted RCTs are warranted to explore this effect further.

Transgenic autoinhibition of p21-activated kinase exacerbates synaptic impairments and fronto-dependent behavioral deficits in an animal model of Alzheimer's disease

Defects in p21-activated kinase (PAK) lead to dendritic spine abnormalities and are sufficient to cause cognition impairment. The decrease in PAK in the brain of Alzheimer's disease (AD) patients is suspected to underlie synaptic and dendritic disturbances associated with its clinical expression, particularly with symptoms related to frontal cortex dysfunction. To investigate the role of PAK combined with Aβ and tau pathologies (3xTg-AD mice) in the frontal cortex, we generated a transgenic model of AD with a deficit in PAK activity (3xTg-AD-dnPAK mice). PAK inactivation had no effect on Aβ40 and Aβ42 levels, but increased the phosphorylation ratio of tau in detergent-insoluble protein fractions in the frontal cortex of 18-month-old heterozygous 3xTg-AD mice. Morphometric analyses of layer II/III pyramidal neurons in the frontal cortex showed that 3xTg-AD-dnPAK neurons exhibited significant dendritic attrition, lower spine density and longer spines compared to NonTg and 3xTg-AD mice. Finally, behavioral assessments revealed that 3xTg-AD-dnPAK mice exhibited pronounced anxious traits and disturbances in social behaviors, reminiscent of fronto-dependent symptoms observed in AD. Our results substantiate a critical role for PAK in the genesis of neuronal abnormalities in the frontal cortex underlying the emergence of psychiatric-like symptoms in AD.

Apathy in Frontotemporal Degeneration: Neuroanatomical Evidence of Impaired Goal-directed Behavior

Background: Apathy, the major manifestation of impaired goal-directed behavior (GDB), is the most common neuropsychiatric syndrome associated with behavioral variant frontotemporal degeneration (bvFTD). The behavioral and biological mechanisms of apathy, however, are not well understood. We hypothesized that GDB has multiple components—including at least initiation, planning and motivation—and that GDB is supported by a network of multiple frontal brain regions. In this study, we examined this hypothesis by evaluating the selective breakdown of GDB in bvFTD, and relating these deficits to gray matter (GM) atrophy and white matter (WM) integrity.

Methods: Eighteen apathetic bvFTD participants and 17 healthy controls completed the Philadelphia Apathy Computerized Test (PACT). This test quantifies each of three components of GDB hypothesized to contribute to apathy. We then used regression analyses to relate PACT scores to GM atrophy and reduced white matter (WM) fractional anisotropy (FA) in bvFTD.

Results: Compared to controls, bvFTD participants demonstrated significant impairments in each of the three hypothesized components of GDB that contribute to apathy. Regression analyses related each component to disease in specific GM structures and associated WM tracts. Poor initiation thus was related to GM atrophy in anterior cingulate and reduced FA in the cingulum. Planning impairment was related to GM atrophy in dorsolateral prefrontal cortex and reduced FA in superior longitudinal fasciculus. Poor motivation was related to GM atrophy in orbitofrontal cortex (OFC) and reduced FA in uncinate fasciculus (UNC).

Conclusions: bvFTD patients have difficulty with initiation, planning and motivation components of GDB. These findings are consistent with the hypotheses that GDB encompasses at least three processes, that these are supported by a large-scale neural network within specific portions of the frontal lobe, and that degradation of any one of these prefrontal regions in bvFTD may contribute to apathy.

Considerations in psychotropic treatments in dementia--can polypharmacy be avoided?

Physicians treating demented individuals are confronted with complex clinical presentations. This complexity results from the multi-factorial nature of clinical phenomena, the aetiologies of these phenomena, which differ from similar symptoms in younger populations, limited physiological reserves and the multiple co-morbidities and medications. This intricacy is well exemplified within the clinical presentation and management of psychological and behavioural symptoms of dementia. The latter are associated with a poor quality of life, increased burden for both patient and caregivers. A further challenge and source for frustration is the fact that many of the medications used to treat cognitive and behavioural symptoms of dementia are only marginally effective or not effective at all, on the one hand, and associated with increased risk for morbidity and mortality on the other hand. In the present review, we discuss these factors in the context of polypharmacy and suggest further clinical and research strategies that may enable more accurate and less harmful therapeutic strategies.

Effects of a non-focal plasticity protocol on apathy in moderate Alzheimer's disease: a randomized, double-blind, sham-controlled trial

BACKGROUND

Apathy is the most common neuropsychiatric symptom in Alzheimer's disease (AD) and it is associated with changes in prefrontal neural circuits involved with generation of voluntary actions. To date no effective treatment for apathy has been demonstrated.

OBJECTIVE

We aimed to investigate the effects and safety of repetitive transcranial direct current stimulation (tDCS) on apathy in moderate AD patients.

METHODS

Forty patients were randomized to receive either active or sham-tDCS over the left dorsolateral prefrontal cortex (DLPFC). Patients received six sessions of intervention during 2 weeks and were evaluated at baseline, at week 1 and 2, and after 1 week without intervention. Clinical raters, patients, and caregivers were blinded. The primary outcome was apathy. Global cognition and neuropsychiatric symptoms were examined as secondary outcomes.

RESULTS

The mean MMSE score at baseline was 15.2 ± 2.9 and the mean Apathy Scale score was 27.7 ± 6.7. Changes on apathy scores over time were not different between active and sham tDCS (P = 0.552 for repeated measures). Further analyses confirm that changes from baseline did not differ between groups after the sixth session (active tDCS -1.95 (95%CI -3.49, -0.41); sham-tDCS -2.05 (95%CI -3.68, -0.42); P = 0.989]. Similarly, tDCS had no effect on secondary outcomes (P > 0.40). tDCS was well tolerated and not associated with significant adverse effects.

CONCLUSION

In this adequately powered study for minimal clinically significant difference, our findings show that using the parameters we chose for this study, repeated anodal tDCS over the left DLPFC had no effect on apathy in elderly patients with moderate AD.

Sex-dependent alterations in social behaviour and cortical synaptic activity coincide at different ages in a model of Alzheimer's disease

Besides memory deficits, Alzheimer's disease (AD) patients suffer from neuropsychiatric symptoms, including alterations in social interactions, which are subject of a growing number of investigations in transgenic models of AD. Yet the biological mechanisms underlying these behavioural alterations are poorly understood. Here, a social interaction paradigm was used to assess social dysfunction in the triple-transgenic mouse model of AD (3xTg-AD). We observed that transgenic mice displayed dimorphic behavioural abnormalities at different ages. Social disinhibition was observed in 18 months old 3xTg-AD males compared to age and sex-matched control mice. In 3xTg-AD females, social disinhibition was present at 12 months followed by reduced social interactions at 18 months. These dimorphic behavioural alterations were not associated with alterations in AD neuropathological markers such as Aβ or tau levels in the frontal cortex. However, patch-clamp recordings revealed that enhanced social interactions coincided temporally with an increase in both excitatory and inhibitory basal synaptic inputs to layer 2-3 pyramidal neurons in the prefrontal cortex. These findings uncover a novel pattern of occurrence of psychiatric-like symptoms between sexes in an AD model. Our results also reveal that functional alterations in synapse activity appear as a potentially significant substrate underlying behavioural correlates of AD.

Pharmacologic treatment of apathy in dementia

Apathy in patients with dementia is common, underrecognized, and undertreated. We sought to improve understanding of the pharmacologic treatment of apathy in dementia by performing a systematic literature review of studies that used apathy outcome scales to document results of pharmacologic treatments for apathy. There is limited evidence of efficiency of pharmacotherapy for treatment of apathy in dementia. The best results were found for acetylcholinesterase inhibitors. There was some evidence of efficacy for memantine, but less evidence of efficacy for stimulants, calcium antagonists, and antipsychotics. There was no evidence to support the use of antidepressants or anticonvulsants. The research quality of studies was modest. Recommendations for standardizing research and for holistic evaluation and treatment are provided.

Use of psychostimulants in patients with dementia

OBJECTIVE

To review the efficacy and safety of psychostimulants for negative behavioral symptoms (ie, apathy, excessive daytime sedation) and cognition in patients with dementia.

DATA SOURCES

Literature was accessed through PubMed and MEDLINE (1966-June 2010), using the terms stimulant, psychostimulant, methylphenidate, dexmethylphenidate, amphetamine, dextroamphetamine, lisdexamfetamine, atomoxetine, modafinil, armodafinil, dementia, Alzheimer disease, vascular dementia, Lewy body dementia, mixed dementia, frontotemporal dementia, therapy, treatment, and therapeutic. Additional references identified from the initial search were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All relevant clinical trials published in English and involving primarily older adults with dementia were included. Case reports, review articles, and other preclinical literature were included as appropriate.

DATA SYNTHESIS

Psychostimulants have been employed as a treatment for cognitive and behavioral symptoms in dementia for decades, but the literature has lagged behind this practice. Eight reports on use of psychostimulants as a treatment of apathy in dementia were reviewed. Methylphenidate was the most frequently studied medication and improvements in apathy were consistently noted; however, the magnitude and duration of effect remain unclear. Six studies examining the cognitive effects of a variety of psychostimulants in patients with dementia were reviewed; psychostimulants had little to no effect on cognition. A lack of studies exists to draw conclusions about the use of psychostimulants for the treatment of excessive daytime sedation in dementia. The possibility of psychostimulants to increase blood pressure; elevate heart rate; and lead to irritability, agitation, and psychosis makes careful patient selection critical, especially in older adults with severe cardiovascular disease or other underlying cardiac abnormalities.

CONCLUSIONS

Based on limited studies, methylphenidate is a possible treatment for apathy in patients with dementia. Psychostimulants, as a group, do not appear to be broadly effective treatments for behavioral or cognitive symptoms of dementia. The potential utility of psychostimulants must be balanced with careful patient selection.