Cognitive rehabilitation in Alzheimer's disease

Christos Voucharas ,Christos G.TsagkarisDimitrios V.MoysidisAndreas S.Papazoglou

1 School of Medicine,Faculty of Health Sciences,Aristotle University of Thessaloniki,Thessaloniki,Greece

2 School of Medicine,Faculty of Health Sciences,University of Crete,Heraklion,Greece

Abstract

Key words:Alzheimer's disease；cognitive enhancement；cognitive rehabilitation；cognitive stimulation；cognitive training；cost；review

INTRODUCTION

Cognitive rehabilitation (CR) has been defined as a comprehensive program aiming to cognitive enhancement.CR includes several training approaches and has been developed as a method of rehabilitation for people with cognitive impairment of various etiologies.CR has been studied as a part of the treatment of several conditions,including traumatic brain injury,cerebral vascular accident,cerebral palsy,Down syndrome,Alzheimer's disease (AD),attention deficit hyperactivity disorder,and developmental disorders such as Autism,Schizophrenia,and Parkinson's disease.1

Due to the low efficacy of pharmacological approaches to the day,CR is expected to play an important role in AD's treatment.In CR,all facets of neuropsychological deficits are approached in the context of behavior and social functioning.Practitioners pay special attention to cognitive stimulation and training.Clare and Woods published their work on cognitive enhancement in AD back in 2004,and grouped the various treatments into three broad categories:cognitive stimulation,cognitive training,and cognitive rehabilitation.2

This review aims to present CR as a mental enhancement strategy in AD and to state the worth of CR on patients with AD,the benefits and drawbacks,the cost and the overall implementation,as well as the optimal future approach of the strategy (Figure1).

DATABASE SEARCH STRATEGY

The authors electronically searched the PubMed database as well as the Google search tool.The key words were Alzheimer's disease treatment,cognitive enhancement,cognitive rehabilitation,cognitive stimulation,and cognitive training.English-language and full-text articles published from 1992 to the present were included in this review.The results were further screened by title and abstract to exclude interventional or pharmacological approaches in AD treatment strategies；CR in psychiatric disorders was also excluded.

Figure1:Cognitive rehabilitation for Alzheimer's disease reviewed in this work.

NEUROPSYCHOLOGICAL BACKGROUND

The idea of cognitive treatments for AD is based on the concept of neuronal plasticity.A continuous loss of cerebral capacity including neuromodulation has been related to aging.Accumulating evidence recommends that the sensory system is capable of altering its structural and functional patterns in accordance to various stimuli.To put it in plain words,this means that the mind has the capacity for rebuilding itself so as to adjust to changing conditions or novel stressors.This feature has been established through plasticity promoting studies in ordinary older individuals.1

Patients' engagement and training represent a repeated stimulus which enhances signaling pathways and eventually gene expression in molecular and cellular levels.Consequently they appear as promising methods of inducing brain plasticity since they involves individuals in stimulating cognitive,sensory,and psychomotor tasks.3

Several neuropsychological experiments or clinical studies support the efficacy of cognitive engagement and training.Most of these studies focus on visual stimuli4-7and suggest that the main cerebral areas affected by training experiments are the right fusiform face area,the right parahippocampal cortex,the right temporal-parietal junction,and the right medial prefrontal cortex.8-10The efficacy of training could be assessed through either higher or lower activation of neural circuits.Higher activation has been correlated with higher functionality,whereas in different studies,lower activation is considered an encouraging finding,suggesting that a task can be accomplished easier.11

On these grounds,we assume that neurons which undergo these procedures can act as an assembly enhancing memory patterns and networks.This applies to existing memory patterns,which are enhanced and may also be able to form new patterns.A very important aspect of this concept is that minority neuron circuits may be enhanced and in functional level,this signifies that an individual who faces a working memory impairment could witness an improvement of his daily life through cognitive training.1,12

COGNITIVE REHABILITATION AS A MENTALENHANCEMENT STRATEGY IN ALZHEIMER'S DISEASE

CR is defined as a comprehensive cognitive enhancement program,which encompasses cognitive stimulation,cognitive training and other approaches.Cognitive stimulation focuses on the patient's participation in discussions about his familiar daily affairs in order to stimulate mental activity.More impaired AD patients and mainly inpatients in proper facilities are usually treated with cognitive stimulation.Furthermore,cognitive training consists of various tasks designed to exercise specific cognitive functions or to work on patients with a relatively fair cognitive status so as to support its impaired aspects.Consequently,patients who have enough cognitive resources for a therapist or a computer program to guide them are usually treated with cognitive training.5,6,13-15

As a combination of the aforementioned methods,CR functions as a model of treating the cognitive decline depending on the assessed behavioral and social disabilities rather than focusing on specific cognitive deficits.In this frame,CR not only alleviates cognitive deficits working closely on them,but also creates compensatory mnemonic pathways so as to restore the functionality of the patient to the greatest extent.This compensation ranges from training the patients to dealing with finances in such a way that the monthly utility bills are easier to remember,to learning how to use virtual or paper aids to organize and recall important information (such as medication and appointments).Verbal instructions along with physical demonstration and support items are used to teach the patient how to develop methods applicable to its own cognitive deficits.The outcomes of CR can be observed and assessed during the interaction between the patient and his/her environment.13,14,16

A comfortable setting such as the patient's home plays an important role in the efficacy of the intervention.Moreover,CR ought to be perceived as a dynamic procedure in which the patient and his family/carers are actively involved assisted and coordinated by the health professional who acts as therapist.The patient should be encouraged to practice the strategies he/she elaborated on during the session on his own and apply them to as many of his daily activities as possible.Simultaneously,the family/carers should be debriefed after each session and also be instructed with strategies for practice outside the CR sessions.13,14,17

Evidence suggests that the outcomes of CR should be assessed in the beginning and in the end of each CR session,in the short and long terms.Moreover,it is considered useful for the health professional and for the family/carers of the patient to take notes so as to better observe the capacity of the patient to deal with everyday tasks.Although scientific studies systematically observe and evaluate the efficacy of any tested approach,such an individual monitoring appears as an essential part of each treatment plan and it seems to be helpful as far as the personalization of CR,the commitment of the patient and the therapist - patient communication are concerned.11,13,17

EFFICACY OF COGNITIVE REHABILITATION IN ALZHEIMER'S DISEASE PATIENTS

The efficacy of CR in AD has been debated for a long time.Back in 1999,a National Institutes of Health resolution pointed out that few studies are available and even these studies are greatly diverse as far as their methods are concerned or present data from a small number of patients.18

More specifically,Heiss et al.19conducted a positron emission tomography study of 70 patients with mild AD comparing social support,pharmacological and/or cognitive treatment.Their results suggest that a combination of cognitive training and pharmacological treatment (phosphatidylserine or pyritinol) was associated with increased brain glucose metabolism in temporal-parietal brain areas during a task based on recognition of visual stimuli.

Other studies showed a progressive decrease in the neuronal activity associated with the accomplishment of a task upon CR training.A study from Haier et al.20included young individuals performing repeatedly a complex visuospatial/motor task.The individuals underwent brain positron emission tomography scans before and after practice.20Results revealed a decrease in regional subcortical glucose metabolic rate with practice,which may reflect changes in cognitive strategy that are a part of the learning process.20

Such findings create a body of evidence supporting its efficacy and hence allowing wider studies to be conducted.

BENEFITS AND DRAWBACKS OF COGNITIVE REHABILITATION ON PATIENTS WITH ALZHEIMER'S DISEASE

CR is a non-interventional,non-pharmaceutical personalized treatment.Both the patients and the carers are engaged in the therapeutic procedure and hence a viable therapeutic relation is established according to the principles of biopsychosocial healthcare.Various health professionals (occupational therapists,physical therapists,speech/language pathologists,neuropsychologists,psychiatrists or other physicians) can be trained to perform CR and thus many patients in different settings will have access to CR.21-23

However,CR has several drawbacks with regards to the method in general and the application of the method to patients with AD in particular.In the first category,we may list the variable efficacy of the method depending on the experience of the therapist,the ambivalent efficacy - which discourages health professionals from considering it as a treatment for their patients - and the fact that carers should be engaged to achieve optimal compliance and efficacy.13

In the second category,we may refer to indigenous factors of the disease.The progressive mental decline,the patient's low understanding or even awareness of the illness and the highly prevalent depression among geriatric patients have been shown to alter the potential outcomes of CR.As a result,the purpose of CR in AD is to slow down this cognitive decline offering to the patient some months of independent or less dependent function.24Even though this is considered as a huge benefit in terms of quality of life and care associated direct and indirect costs,it does not meet the expectations of the patients'carers and this results in a lower level of carers' engagement weakening the overall efficacy of the treatment.1

COST AND OVERALL IMPLEMENTATION OVERVIEW

The cost is an important factor which already affects CR implementation.Many US based insurance brands refuse to cover CR expenses in patients suffering from different conditions other than traumatic brain injury and cerebral vascular accident.Medicare documents also reveal a similar attitude of the US public sector towards CR in AD.The cost of CR interventions varies depending on its methods.Interventions based on computer programs cost more than interventions based on simple notepads.

Contemporary studies investigate cost-benefit aspects of the low-cost CR.Their findings suggest that CR will be covered for AD patients on the grounds of (1) neuropsychological testing:neuropsychological results will direct treatment planning and rehabilitation strategies,(2) neuropsychiatric and neuropsychological evaluation,(3) ability of the patient to actively participate in a CR program (e.g.,is not comatose or in a vegetative state)；and (4) an expected significant amelioration of the patient's cognitive status.25-29

TOWARDS AN OPTIMAL COGNITIVE REHABILITATION

Future studies will need to support CR's scientific rather than empirical character,provide practitioners with constant updates to and establish a feedback network between practitioners and researchers.Moreover,CR ought probably to be aligned with the principles of errorless learning.Errorless learning has been designed to make sure that the patient memorizes accurately and correctly in order to maximize the duration of the gained functionality.This approach appears as the most promising one and is expected to reform all existing kinds of CR.30All in all,the concept and the implementation of CR enhance the role of patient centered and behavioral approach in the field of AD therapeutics.31,32

Author contributions

Data collection,manuscript supervisor,critical revision:CV；manuscript drafting and writing:CGT,DVM and ASP.All authors have read and approved the final manuscript.

Conflicts of interest

None declared.

Financial support

None.

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Checked twice by iThenticate.

Peer review

Externally peer reviewed.

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