Alzheimer's disease and implicit memory

Prefrontal theta-gamma transcranial alternating current stimulation improves non-declarative visuomotor learning in older adults

The rise in the global population of older adults underscores the significance to investigate age-related cognitive disorders and develop early treatment modalities. Previous research suggests that non-invasive transcranial Alternating Current Stimulation (tACS) can moderately improve cognitive decline in older adults. However, non-declarative cognition has received relatively less attention. This study investigates whether repeated (16-day) bilateral theta-gamma cross-frequency tACS targeting the Dorsolateral Prefrontal Cortex (DLPFC) enhances non-declarative memory. Computerized cognitive training was applied alongside stimulation to control for the state-of-the-brain. The Alternating Serial Reaction Time (ASRT) task was employed to assess non-declarative functions such as visuomotor skill and probabilistic sequence learning. Results from 35 participants aged 55-82 indicated that active tACS led to more substantial improvements in visuomotor skills immediately after treatment, which persisted 3 months later, compared to sham tACS. Treatment benefit was more pronounced in older adults of younger age and those with pre-existing cognitive decline. However, neither intervention group exhibited modulation of probabilistic sequence learning. These results suggest that repeated theta-gamma tACS can selectively improve distinct non-declarative cognitive aspects when targeting the DLPFC. Our findings highlight the therapeutic potential of tACS in addressing deficits in learning and retaining general skills, which could have a positive impact on the quality of life for cognitively impaired older individuals by preserving independence in daily activities.

Altered local and remote functional connectivity in mild Alzheimer's disease patients with sleep disturbances

Objectives

This study aimed to investigate local and remote functional connectivity in mild Alzheimer's disease patients with sleep disturbances (ADSD) and those without sleep disturbances (ADNSD).

Methods

Thirty eight mild AD patients with sleep disturbances and 21 mild AD patients without sleep disturbances participated in this study. All subjects underwent neuropsychological assessments and 3.0 Tesla magnetic resonance scanning. Static and dynamic regional homogeneity (ReHo) were used to represent the local functional connectivity. Seed-based whole-brain functional connectivity was used to represent the remote functional connectivity. The seed was chosen based on the results of ReHo.

Results

Compared to ADNSD, ADSD showed decreased static ReHo in the left posterior central gyrus and the right cuneus and increased dynamic ReHo in the left posterior central gyrus. As for the remote functional connectivity, comparing ADSD to ADNSD, it was found that there was a decreased functional connection between the left posterior central gyrus and the left cuneus as well as the left calcarine.

Conclusion

The current study demonstrated that, compared with ADNSD, ADSD is impaired in both local and remote functional connectivity, manifested as reduced functional connectivity involving the primary sensory network and the primary visual network. The abnormality of the above functional connectivity is one of the reasons why sleep disorders promote cognitive impairment in AD. Moreover, sleep disorders change the temporal sequence of AD pathological damage to brain functional networks, but more evidence is needed to support this conclusion.

Memories without Survival: Personal Identity and the Ascending Reticular Activating System

Lockean views of personal identity maintain that we are essentially persons who persist diachronically by virtue of being psychologically continuous with our former selves. In this article, I present a novel objection to this variant of psychological accounts, which is based on neurophysiological characteristics of the brain. While the mental states that constitute said psychological continuity reside in the cerebral hemispheres, so that for the former to persist only the upper brain must remain intact, being conscious additionally requires that a structure originating in the brainstem-the ascending reticular activating system-be functional. Hence, there can be situations in which even small brainstem lesions render individuals irreversibly comatose and thus forever preclude access to their mental states, while the neural correlates of the states themselves are retained. In these situations, Lockeans are forced to regard as fulfilled their criterion of diachronic persistence since psychological continuity, as they construe it, is not disrupted. Deeming an entity that is never again going to have any mental experiences to be a person, however, is an untenable position for a psychological account to adopt. In their current form, Lockean views of personal identity are therefore incompatible with human neurophysiology.

Nondeclarative associative learning in Alzheimer's disease: An overview of eyeblink, fear, and other emotion-based conditioning

Alzheimer's disease is a neurodegenerative disorder that is characterized by progressive cognitive decline, particularly in declarative memory, and the presence of β-amyloid plaques, neurofibrillary tangles, and cortical atrophy (especially in the temporal lobe). Unlike the relationship between the temporal cortex and declarative memory, nondeclarative memories (e.g., motor, fear, and other emotion-based memories) involve distinct neural structures. The present review investigates nondeclarative associative learning ability in Alzheimer's disease. We discuss eyeblink conditioning, fear conditioning, and other emotion-based learning and present the functions and brain areas that are involved in each type of learning. Evidence suggests that nondeclarative learning is also affected by Alzheimer's disease, although some forms of learning may be relatively preserved. Details about each nondeclarative associative learning process and the implications of these findings are presented.

A Focused Review on Cognitive Improvement by the Genus Salvia L. (Sage)-From Ethnopharmacology to Clinical Evidence

Ethnopharmacology has been an important starting point in medical and pharmaceutical sciences for discovering drug candidates from natural sources. In this regard, the genus Salvia L., commonly known as sage, is one of the best-known medicinal and aromatic plants of the Lamiaceae family; it has been recorded as being used for memory enhancement in European folk medicine. Despite the various uses of sage in folk medicines, the records that have pointed out sage's memory-enhancing properties have paved the way for the aforementioned effect to be proven on scientific grounds. There are many preclinical studies and excellent reviews referring to the favorable effect of different species of sage against the cognitive dysfunction that is related to Alzheimer's disease (AD). Hence, the current review discusses clinical studies that provide evidence for the effect of Salvia species on cognitive dysfunction. Clinical studies have shown that some Salvia species, i.e., hydroalcoholic extracts and essential oils of S. officinalis L. and S. lavandulaefolia leaves in particular, have been the most prominently effective species in patients with mild to moderate AD, and these species have shown positive effects on the memory of young and healthy people. However, the numbers of subjects in the studies were small, and standardized extracts were not used for the most part. Our review points out to the need for longer-term clinical studies with higher numbers of subjects being administered standardized sage preparations.

Global Clinical Dementia Rating Score of 0.5 May Not Be an Accurate Criterion to Identify Individuals with Mild Cognitive Impairment

Many studies use the global clinical dementia rating (CDR) of 0.5 as a criterion for mild cognitive impairment, but past studies have not fully discussed its validity. The authors developed the ABC Dementia Scale (ABC-DS) to accurately monitor the changes in activities for daily living, behavioral and psychological symptoms of dementia, and cognitive function. When we carried out a cluster analysis of ABC-DS scores of 110 individuals for whom global CDR was 0.5, there were three groups with different levels of activities for daily living and cognitive function. O’Bryant et al. proposed a new guideline to stage dementia using the CDR sum of boxes scores (CDR-SOB). We used their proposal and ABC-DS scores to evaluate the validity of CDR 0.5 as a definition of mild cognitive impairment (MCI). We concluded that the CDR-SOB scores and ABC-DS score are more accurate than global CDR of 0.5 for specifying individuals with MCI.

Accepting the Challenge-Moderate-Intensity Exercise with Individuals with Dementia: A Case Series

Background and purpose:

The global impact of dementia demands a response from researchers and clinicians to not only assist with prevention and a cure, but also to assist in the management of symptoms related to this progressive disease. The purpose of this case series is to highlight the participation of 3 individuals with varying levels of dementia in a moderate-intensity functional exercise program.

Intervention:

The intervention, developed using principles from exercise science and a Strength-Based Approach, consisted of 24 sessions of moderate-intensity exercises delivered in participant’s home.

Outcomes:

Each participant completed a pre- and post-assessment including gait speed, strength, balance, depressive symptoms, cognition, and perceived difficulty with activities of daily living. Despite various clinical presentations, each participant successfully completed all 24 sessions with noted improvements in at least two measures.

Discussion:

These findings highlight the flexibility of using the Strength-Based Approach to enhance participation in a standardized exercise program.

Schizophrenia and Corollary Discharge: A Neuroscientific Overview and Translational Implications

Corollary discharge mechanism refers to the suppression of sensory consequences of self-generated actions; a process that serves to distinguish between self and non-self based on discrimination of origination of action. It explains, say for example, why we cannot tickle ourselves. This review discusses how corollary discharge model is an essential neural integration mechanism central to the motor functioning of animal kingdom. In this article, research conducted in the field of corollary discharge has been reviewed to understand the neuroanatomical and neurophysiological basis of corollary discharge and gain insight into the biochemical basis of its dysfunction. This review article also explores the role of corollary discharge and its dysfunction in the presentation of symptoms of schizophrenia, discussing the findings from corollary discharge studies on schizophrenia population. Lastly, the link between schizophrenia psychopathology and corollary discharge dysfunction has been highlighted, and an attempt has been made to establish a case for correction of corollary discharge deficit in schizophrenia through neuromodulation.

Differential Contributions of Selective Attention and Sensory Integration to Driving Performance in Healthy Aging and Alzheimer's Disease

OBJECTIVES

Patients with Alzheimer's disease (AD) demonstrate deficits in cross-cortical feature binding distinct from age-related changes in selective attention. This may have consequences for driving performance given its demands on multisensory integration. We examined the relationship of visuospatial search and binding to driving in patients with early AD and elderly controls (EC).

METHODS

Participants (42 AD; 37 EC) completed search tasks requiring either luminance-motion (L-M) or color-motion (C-M) binding, analogs of within and across visual processing stream binding, respectively. Standardized road test (RIRT) and naturalistic driving data (CDAS) were collected alongside clinical screening measures.

RESULTS

Patients performed worse than controls on most cognitive and driving indices. Visual search and clinical measures were differentially related to driving behavior across groups. L-M search and Trail Making Test (TMT-B) were associated with RIRT performance in controls, while C-M binding, TMT-B errors, and Clock Drawing correlated with CDAS performance in patients. After controlling for demographic and clinical predictors, L-M reaction time significantly predicted RIRT performance in controls. In patients, C-M binding made significant contributions to CDAS above and beyond demographic and clinical predictors. RIRT and C-M binding measures accounted for 51% of variance in CDAS performance in patients.

CONCLUSIONS

Whereas selective attention is associated with driving behavior in EC, cross-cortical binding appears most sensitive to driving in AD. This latter relationship may emerge only in naturalistic settings, which better reflect patients' driving behavior. Visual integration may offer distinct insights into driving behavior, and thus has important implications for assessing driving competency in early AD. (JINS, 2018, 24, 486-497).

Candy eating behaviour to improve swallowing function in dementia subjects

OBJECTIVES

To develop and assess a dysphagia training method involving lollipop sucking training in older adults with dementia, clarify its effectiveness for improving oral function.

METHODS

Twenty-five older adults with dementia (5 males and 20 females, mean age 90.8 ± 6.7 years) were participated in this study. Participants were trained in lollipop sucking once a day, 3 times a week for 6 months. Mini-Mental State Examination (MMSE), Barthel Index (BI), Candy Sucking Test (CST), and BMI values were measured before and after the training. Participants were grouped into those who achieved >0.1 g/min increase in CTS value after the training (increase group) and those who did not (nonincrease group).

RESULTS

No significant change was observed after the training. The increase group contained 4 patients and the non-increase group contained 21 patients. There were no significant differences in MMSE, BI, or BMI between the two groups before and after the training. However, the CST values of the increase group before the training (0.31 ± 0.13 g/min) were significantly lower than non-increase group (0.69 ± 0.27 g/min) (p < 0.01). Respective changes in BMI before and after training were 1.13 ± 0.85 kg/m² and -0.53 ± 1.76 kg/m² in the increase and non-increase, and the difference in these changes was statistically significant (p = 0.04).

CONCLUSIONS

Our new rehabilitation method was well accepted by older adults with dementia, and there was an improvement in oral function as a result of the rehabilitation, which had some good influence on weight gain.

Findings from a strength-based moderate-intensity exercise interventions for individuals with dementia (innovative practice)

Limited evidence exists regarding exercise interventions with individuals with dementia, which is often due to heterogeneity of methodology and outcomes being assessed. This led to the development and evaluation of a moderate-intensity home-based functional exercise program guided by theories from exercise science and the Strength-Based Approach. Data indicated excellent treatment adherence (99.04%) along with high levels of acceptability and feasibility in this sample (age 76.63 years (9.84); Mini Mental State Exam 18.87 (6.40)). This article informs future practice by highlighting the merits of a Strength-Based Approach in research examining exercise and physical rehabilitation to improve adherence and compliance with individuals with dementia.

Within-session and one-week practice effects on a motor task in amnestic mild cognitive impairment

Practice effects on neuropsychological tests, which are improvements in test scores due to repeated exposure to testing materials, are robust in healthy elders, but muted in older adults with cognitive disorders. Conversely, few studies have investigated practice effects on motor tasks involving procedural memory, particularly across test-retest periods exceeding 24 hours. The current study examined one-week practice effects on a novel upper extremity motor task in 54 older adults with amnestic mild cognitive impairment. Results indicate that these individuals with primary memory deficits did improve on this motor task within a brief training session as well as across one week. These practice effects were unrelated to demographic characteristics or global cognition. One-week practice effects were, however, negatively related to delayed memory function, with larger practice effects being associated with poorer delayed memory and potentially better visuospatial ability. The presence of longer term practice effects on a procedural motor task not only has implications for how longitudinal assessments with similar measures involving implicit memory might be interpreted, but may also inform future rehabilitative strategies for patients with more severe declarative memory deficits.

Mnemonic anosognosia in Alzheimer's disease is caused by a failure to transfer online evaluations of performance: Evidence from memory training programs

INTRODUCTION

There is a debate about the ability of patients with Alzheimer's disease to build an up-to-date representation of their memory function, which has been termed mnemonic anosognosia. This form of anosognosia is typified by accurate online evaluations of performance, but dysfunctional or outmoded representations of function more generally.

METHOD

We tested whether people with Alzheimer's disease could adapt or change their representations of memory performance across three different six-week memory training programs using global judgements of learning.

RESULTS

We showed that whereas online assessments of performance were accurate, patients continued to make inaccurate overestimations of their memory performance. This was despite the fact that the magnitude of predictions shifted according to the memory training. That is, on some level patients showed an ability to change and retain a representation of performance over time, but it was a dysfunctional one. For the first time in the literature we were able to use an analysis using correlations to support this claim, based on a large heterogeneous sample of 51 patients with Alzheimer's disease.

CONCLUSION

The results point not to a failure to retain online metamemory information, but rather that this information is never used or incorporated into longer term representations, supporting but refining the mnemonic anosognosia hypothesis.

Effectiveness of different memory training programs on improving hyperphagic behaviors of residents with dementia: a longitudinal single-blind study

BACKGROUND

Hyperphagia increases eating-associated risks for people with dementia and distress for caregivers. The purpose of this study was to compare the long-term effectiveness of spaced retrieval (SR) training and SR training combined with Montessori activities (SR + M) for improving hyperphagic behaviors of special care unit residents with dementia.

METHODS

The study enrolled patients with dementia suffering from hyperphagia resident in eight institutions and used a cluster-randomized single-blind design, with 46 participants in the SR group, 49 in the SR + M group, and 45 participants in the control group. For these three groups, trained research assistants collected baseline data on hyperphagic behavior, pica, changes in eating habits, short meal frequency, and distress to caregivers. The SR and SR + M groups underwent memory training over a 6-week training period (30 sessions), and a generalized estimating equation was used to compare data of all the three groups of subjects obtained immediately after the training period and at follow-ups 1 month, 3 months, and 6 months later.

RESULTS

Results showed that the hyperphagic and pica behaviors of both the SR and SR + M groups were significantly improved (P<0.001) and that the effect lasted for 3 months after training. The improvement of fast eating was significantly superior in the SR + M group than in the SR group. The improvement in distress to caregivers in both intervention groups lasted only until the posttest. Improvement in changes in eating habits of the two groups was not significantly different from that of the control group.

CONCLUSION

SR and SR + M training programs can improve hyperphagic behavior of patients with dementia. The SR + M training program is particularly beneficial for the improvement of rapid eating. Caregivers can choose a suitable memory training program according to the eating problems of their residents.

Myricetin protects hippocampal CA3 pyramidal neurons and improves learning and memory impairments in rats with Alzheimer's disease

There is currently no treatment for effectively slowing the progression of Alzheimer's disease, so early prevention is very important. Numerous studies have shown that flavonoids can improve memory impairment. The present study investigated the effects of myricetin, a member of the flavonoids, on intracerebroventricular streptozotocin induced neuronal loss and memory impairment in rat models of Alzheimer's disease. Myricetin at 5 or 10 mg/kg was intraperitoneally injected into rats over 21 days. Control rats were treated with 10 mL/kg saline. Behavioral test (the shuttle box test) was performed on day 22 to examine learning and memory in rats. Immediately after that, hematoxylin-eosin staining was performed to observe the morphological change in hippocampal CA3 pyramidal neurons. Myricetin greatly increased the number of hippocampal CA3 pyramidal neurons and improved learning and memory impairments in rats with Alzheimer's disease. These findings suggest that myricetin is beneficial for treatment of Alzheimer's disease.

Relationship of contextual cueing and hippocampal volume in amnestic mild cognitive impairment patients and cognitively normal older adults

There is currently some debate as to whether hippocampus mediates contextual cueing. In the present study, we examined contextual cueing in patients diagnosed with mild cognitive impairment (MCI) and healthy older adults, with the main goal of investigating the role of hippocampus in this form of learning. Amnestic MCI (aMCI) patients and healthy controls completed the contextual cueing task, in which they were asked to search for a target (a horizontal T) in an array of distractors (rotated L's). Unbeknownst to them, the spatial arrangement of elements on some displays was repeated thus making the configuration a contextual cue to the location of the target. In contrast, the configuration for novel displays was generated randomly on each trial. The difference in response times between repeated and novel configurations served as a measure of contextual learning. aMCI patients, as a group, were able to learn spatial contextual cues as well as healthy older adults. However, better learning on this task was associated with higher hippocampal volume, particularly in right hemisphere. Furthermore, contextual cueing performance was significantly associated with hippocampal volume, even after controlling for age and MCI status. These findings support the role of the hippocampus in learning of spatial contexts, and also suggest that the contextual cueing paradigm can be useful in detecting neuropathological changes associated with the hippocampus.

Aromatherapy for dementia

BACKGROUND

Complementary therapy has received great interest within the field of dementia treatment and the use of aromatherapy and essential oils is increasing. In a growing population where the majority of patients are treated by US Food and Drug Administration (FDA)-approved drugs, the efficacy of treatment is short term and accompanied by negative side effects. Utilisation of complimentary therapies in dementia care settings presents as one of few options that are attractive to practitioners and families as patients often have reduced insight and ability to verbally communicate adverse reactions. Amongst the most distressing features of dementia are the behavioural and psychological symptoms. Addressing this facet has received particular interest in aromatherapy trials, with a shift in focus from reducing cognitive dysfunction to the reduction of behavioural and psychological symptoms in dementia.

OBJECTIVES

To assess the efficacy of aromatherapy as an intervention for people with dementia.

SEARCH METHODS

ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register, was searched on 26 November 2012 and 20 January 2013 using the terms: aromatherapy, lemon, lavender, rose, aroma, alternative therapies, complementary therapies, essential oils.

SELECTION CRITERIA

All relevant randomised controlled trials were considered. A minimum length of a trial and requirements for follow-up were not included, and participants in included studies had a diagnosis of dementia of any type and severity. The review considered all trials using fragrance from plants defined as aromatherapy as an intervention with people with dementia and all relevant outcomes were considered.

DATA COLLECTION AND ANALYSIS

Titles and abstracts extracted by the searches were screened for their eligibility for potential inclusion in the review. For Burns 2011, continuous outcomes were estimated as the mean difference between groups and its 95% confidence interval using a fixed-effect model. For Ballard 2002, analysis of co-variance was used for all outcomes, with the nursing home being treated as a random effect.

MAIN RESULTS

Seven studies with 428 participants were included in this review; only two of these had published usable results. Individual patient data were obtained from one trial (Ballard 2002) and additional analyses performed. The additional analyses conducted using individual patient data from Ballard 2002 revealed a statistically significant treatment effect in favour of the aromatherapy intervention on measures of agitation (n = 71, MD -11.1, 95% CI -19.9 to -2.2) and behavioural symptoms (n = 71, MD -15.8, 95% CI -24.4 to -7.2). Burns 2011, however, found no difference in agitation (n = 63, MD 0.00, 95% CI -1.36 to 1.36), behavioural symptoms (n = 63, MD 2.80, 95% CI -5.84 to 11.44), activities of daily living (n = 63, MD -0.50, 95% CI -1.79 to 0.79) and quality of life (n = 63, MD 19.00, 95% CI -23.12 to 61.12). Burns 2011 and Fu 2013 found no difference in adverse effects (n = 124, RR 0.97, 95% CI 0.15 to 6.46) when aromatherapy was compared to placebo.

AUTHORS' CONCLUSIONS

The benefits of aromatherapy for people with dementia are equivocal from the seven trials included in this review. It is important to note there were several methodological difficulties with the included studies. More well-designed, large-scale randomised controlled trials are needed before clear conclusions can be drawn regarding the effectiveness of aromatherapy for dementia. Additionally, several issues need to be addressed, such as whether different aromatherapy interventions are comparable and the possibility that outcomes may vary for different types of dementia.

Computerized adaptation of The Placing Test for early detection of both mild cognitive impairment and Alzheimer's disease

Changes in the hippocampal system have been proposed as a possible marker of incipient Alzheimer's disease (AD) at the mild cognitive impairment (MCI) stage. The Placing Test (TPT) evaluates the efficiency of the hippocampal system by measuring the ability to remember associations between images and their locations. Our aim was to validate a novel paper-and-pencil (PnP) version of TPT featuring people's faces in color (versus the traditional test carried out with black-and-white images) and a computerized Placing test with categories of objects, faces, and animals (versus a version featuring the categories of objects, faces, and shapes). A total of 78 subjects were divided into 2 groups; each group included 20 normal control subjects, 10 subjects with MCI, and 9 with AD. All subjects underwent TPT. The correlation between the two versions of the test was highly significant (r=.770, p<.001), demonstrating that the transfer of the test format from PnP to computer was acceptable. Computerized object and animal subtests had the highest overall sensitivity and specificity for discriminating MCI from AD, while PnP faces in color discriminated controls from MCI best. Although this was a preliminary assessment on a small sample of subjects, the results of our study demonstrated that total scores on both the traditional and computerized versions of the test discriminate all three diagnostic categories, but the subtests had varying discriminatory abilities.

The moderating effect of nutritional status on depressive symptoms in veteran elders with dementia: a spaced retrieval combined with Montessori-based activities

AIM

To examine the long-term effects of fixed/individualized spaced retrieval combined with Montessori-based activities on nutritional status and body mass index and nutritional improvement's moderating effect on depressive symptoms for people with dementia during a specific follow-up period.

BACKGROUND

The decrease in food intake, often combined with poor nutrition, may induce depressive symptoms in people with dementia.

DESIGN

A single-blind, quasi-experimental study with repeated measures.

METHODS

Twenty-five fixed group participants received spaced retrieval combined with Montessori-based activities over 24 sessions. Thirty-eight individualized group participants received the same intervention with different sessions, which was adjusted according to each participant's learning response. Twenty-seven control group participants just received routine care. The Chinese version of the Mini-Nutritional Assessment and Cornell Scale for Depression in Dementia scores and body mass index were recorded at pre-test, posttest and 1-, 3- and 6-month follow-ups. Data were collected between July 2008-February 2010.

RESULTS

The Mini-Nutritional Assessment scores and body mass index of the fixed and individualized groups could be significantly increased over time. Additionally, the Cornell Scale for Depression in Dementia scores could be significantly reduced as a result of the improvement of the Mini-Nutritional Assessment scores arising from the individualized intervention.

CONCLUSION

The depressive symptoms of residents with dementia could be moderated by the individualized intervention through nutritional improvement. Trained clinical nurse specialists can use this individualized intervention for residents with dementia who also have poor nutrition and depressive symptoms.

Lexical Priming in Alzheimer's Disease and Aphasia

Lexical priming was examined in patients with Alzheimer's disease and in aphasic patients. Control participants were divided into young and elderly [cf. Arroyo-Anlló et al.: Eur J Cogn Psychol 2004;16:535-553]. For lexical priming, a word-stem completion task was used. Normal elderly participants had lexical priming scores that were significantly lower than those of young individuals. Analysis of covariance with age and educational level as covariates showed that the control participants, aphasic and Alzheimer patients did not differ significantly on the lexical priming task. Our results suggest that performance in the lexical priming task diminishes with physiological aging, but is not significantly affected by mild or moderate Alzheimer's disease or by fluent or non-fluent aphasia.

Sensorimotor integration and psychopathology: motor control abnormalities related to psychiatric disorders

OBJECTIVES

Recent evidence is reviewed to examine relationships among sensorimotor and cognitive aspects in some important psychiatry disorders. This study reviews the theoretical models in the context of sensorimotor integration and the abnormalities reported in the most common psychiatric disorders, such as Alzheimer's disease, autism spectrum disorder and squizophrenia.

METHODS

The bibliographical search used Pubmed/Medline, ISI Web of Knowledge, Cochrane data base and Scielo databases. The terms chosen for the search were: Alzheimer's disease, AD, autism spectrum disorder, and Squizophrenia in combination with sensorimotor integration. Fifty articles published in English and were selected conducted from 1989 up to 2010.

RESULTS

We found that the sensorimotor integration process plays a relevant role in elementary mechanisms involved in occurrence of abnormalities in most common psychiatric disorders, participating in the acquisition of abilities that have as critical factor the coupling of different sensory data which will constitute the basis of elaboration of consciously goal-directed motor outputs. Whether these disorders are associated with an abnormal peripheral sensory input or defective central processing is still unclear, but some studies support a central mechanism.

CONCLUSION

Sensorimotor integration seems to play a significant role in the disturbances of motor control, like deficits in the feedforward mechanism, typically seen in AD, autistic and squizophrenic patients.