Effects of short-term transcutaneous electrical nerve stimulation on memory and affective behaviour in patients with probable Alzheimer's disease

Brain Stimulation in Alzheimer's Disease

Brain stimulation techniques can modulate cognitive functions in many neuropsychiatric diseases. Pilot studies have shown promising effects of brain stimulations on Alzheimer's disease (AD). Brain stimulations can be categorized into non-invasive brain stimulation (NIBS) and invasive brain stimulation (IBS). IBS includes deep brain stimulation (DBS), and invasive vagus nerve stimulation (VNS), whereas NIBS includes transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), electroconvulsive treatment (ECT), magnetic seizure therapy (MST), cranial electrostimulation (CES), and non-invasive VNS. We reviewed the cutting-edge research on these brain stimulation techniques and discussed their therapeutic effects on AD. Both IBS and NIBS may have potential to be developed as novel treatments for AD; however, mixed findings may result from different study designs, patients selection, population, or samples sizes. Therefore, the efficacy of NIBS and IBS in AD remains uncertain, and needs to be further investigated. Moreover, more standardized study designs with larger sample sizes and longitudinal follow-up are warranted for establishing a structural guide for future studies and clinical application.

Effects of peripheral tactile nerve stimulation on affective behavior of patients with probable Alzheimer's disease

In the present study, the hypothesis was tested that peripheral tactile nerve stimulation by massage would improve various aspects of affective behavior in patients with probable Alzheimer's disease. It was assumed that peripheral tactile stimulation might activate higher-level brain structures (e.g. the hypothalamus). The present study revealed that patients who were stimulated with tactile stimulation felt less depressed, less anxious, more well tempered, and were more alert. Apart from that, their personal orientation and their environmental orientation in place improved, they were more interested in social contacts and they participated more in activities of daily living. However, the observed effects could not be maintained over a period of six weeks following treatment.

Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on Self-Efficacy and Mood in Elderly with Mild Cognitive Impairment

In previous studies, transcutaneous electrical nerve stimulation (TENS) has been applied to patients with either Alzheimer’s disease (AD) or incipient dementia, resulting in an enhancement in memory and verbal fluency. Moreover, affective behavior was shown to improve. Based on the positive effects of TENS in AD, it was hypothesized that TENS would improve self-efficacy in nondemented elderly with mild cognitive impairment (MCI) who live in a residential home. Four outcome measures, that is, a Dutch translation of the General Self-Efficacy Scale (Algemene Competentie Schaal), the Groninger Activity Restriction Scale, the Philadelphia Geriatric Center Morale Scale, and the Geriatric Depression Scale, were administered. Overall, the results suggest that the experimental group showed a mild improvement in self-efficacy and mood. In contrast, the placebo group showed a considerable reduction in self-efficacy and an increase in depression. Limitations of the present study and suggestions for future research are discussed.

Reactivation of atrophic neurons in Alzheimer's disease

Decreased metabolic rate may precede cognitive impairment in Alzheimer's disease (AD) and is thus an early occurring hallmark. Several observations in post-mortem brain indicate that activated neurons are better able to withstand aging and AD, a phenomenon paraphrased by us as 'use it or lose it'. Moreover, a number of pharmacological and nonpharmacological studies support the concept that activation of the brain has beneficial effects and may to a certain degree restore several aspects of cognition and other central functions. For instance, the circadian system may be restimulated in Alzheimer patients by exposing them to more light or transcutaneous nerve stimulation. A procedure has been developed to culture human post-mortem brain tissue that allows testing of the efficacy of putative stimulatory compounds such as neurotrophins.

Supraorbital transcutaneous neurostimulation has sedative effects in healthy subjects

Background

Transcutaneous neurostimulation (TNS) at extracephalic sites is a well known treatment of pain. Thanks to recent technical progress, the Cefaly^® device now also allows supraorbital TNS. During observational clinical studies, several patients reported decreased vigilance or even sleepiness during a session of supraorbital TNS. We decided therefore to explore in more detail the potential sedative effect of supraorbital TNS, using standardized psychophysical tests in healthy volunteers.

Methods

We performed a double-blind cross-over sham-controlled study on 30 healthy subjects. They underwent a series of 4 vigilance tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale, d2 test). Each subject was tested under 4 different experimental conditions: without the neurostimulation device, with sham supraorbital TNS, with low frequency supraorbital TNS and with high frequency supraorbital TNS.

Results

As judged by the results of three tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale) there was a statistically significant (p < 0.001) decrease in vigilance and attention during high frequency TNS, while there were no changes during the other experimental conditions. Similarly, performance on the d2 test was impaired during high frequency TNS, but this change was not statistically significant.

Conclusion

Supraorbital high frequency TNS applied with the Cefaly^® device decreases vigilance in healthy volunteers. Additional studies are needed to determine the duration of this effect, the underlying mechanisms and the possible relation with the stimulation parameters. Meanwhile, this effect opens interesting perspectives for the treatment of hyperarousal states and, possibly, insomnia.

Estimating the effects of right median nerve stimulation on memory in Alzheimer's disease: a randomized controlled pilot study

The goal of the present study was to examine possible effects of right median nerve stimulation (RMNS) on memory in patients in a relatively early stage of probable Alzheimer's disease (AD). Seventeen AD patients were randomly assigned to an experimental group (n = 8) and a control group (n = 9) and treated with RMNS and sham RMNS, respectively, for 30 min a day, 5 days a week, for 6 weeks. Neuropsychological tests were used to assess memory processes. The results show that the various aspects of memory did not respond positively to RMNS. A study with a much longer treatment period is suggested before firm conclusions about the ineffectiveness of RMNS on memory in AD can be drawn.

Peripheral electrical nerve stimulation and rest-activity rhythm in Alzheimer's disease

Rest-activity rhythm disruption is a prominent clinical feature of Alzheimer's disease (AD). The origin of the altered rest-activity rhythm is believed to be degeneration of the suprachiasmatic nucleus (SCN). In accordance with the 'use it or lose it' hypothesis of Swaab [Neurobiol Aging 1991, 12: 317-324] stimulation of the SCN may prevent age-related loss of neurons and might reactivate nerve cells that are inactive but not lost. Previous studies with relatively small sample sizes have demonstrated positive effects of peripheral electrical nerve stimulation on the rest-activity rhythm in AD patients. The present randomized, placebo-controlled, parallel-group study was meant to replicate prior findings of electrical stimulation in AD in a substantially larger group of AD patients. The experimental group (n = 31) received peripheral electrical nerve stimulation and the placebo group (n = 31) received sham stimulation. Effects of the intervention on the rest-activity rhythm were assessed by using wrist-worn actigraphs. Near-significant findings on the rest-activity rhythm partially support the hypothesis that neuronal stimulation enhances the rest-activity rhythm in AD patients. Interestingly, post-hoc analyses revealed significant treatment effects in a group of patients who were not using acetylcholinesterase inhibitors concomitantly. We conclude that more research is needed before firm general conclusions about the effectiveness of electrical stimulation as a symptomatic treatment in AD can be drawn. In addition, the present post-hoc findings indicate that future studies on non-pharmacological interventions should take medication use into account.

Massage and touch for dementia

BACKGROUND

Massage and touch have been suggested as a non-pharmacological alternative or supplement to other treatments offered in order to reduce or manage a range of conditions associated with dementia such as anxiety, agitated behaviour and depression. It has also been suggested that massage and touch may counteract cognitive decline.

OBJECTIVES

To assess the effects of a range of massage and touch therapies on conditions associated with dementia, such as anxiety, agitated behaviour and depression, identify any adverse effects, and provide recommendations about future trials.

SEARCH STRATEGY

We identified trials from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 12 July 2005 using the terms massage, reflexology, touch and shiatsu. This Register contains records from all major healthcare databases and many ongoing trials databases and is updated regularly. In addition, general and specific literature databases were searched and patient and therapist organizations contacted.

SELECTION CRITERIA

Randomized controlled trials (RCTs) in which a massage or touch intervention was given to persons suffering from dementia of any type, compared with other treatments or no treatment, and in which effect parameters included measures of behavioural problems, caregiver burden, emotional distress or cognitive abilities, were eligible for inclusion. Furthermore, we employed a set of minimal methodological quality criteria as a selection filter.

DATA COLLECTION AND ANALYSIS

We identified 34 references in the initial searches. Of these, seven were actual or possible RCTs, but only two were found to meet the requirements of the set of minimal methodological criteria.

MAIN RESULTS

The very limited amount of reliable evidence available is in favour of massage and touch interventions for problems associated with dementia. However, this evidence addresses only two specific applications: hand massage for the immediate or short-term reduction of agitated behaviour, and the addition of touch to verbal encouragement to eat for the normalization of nutritional intake. The existing evidence does not support general conclusions about the effect or possible side effects of such interventions. No severe side effects were identified.

AUTHORS' CONCLUSIONS

Massage and touch may serve as alternatives or complements to other therapies for the management of behavioural, emotional and perhaps other conditions associated with dementia. More research is needed, however, to provide definitive evidence about the benefits of these interventions.

High-Frequency Cranial Electrostimulation (CES) in Patients with Probable Alzheimer’s Disease

In a previous study, low-frequency cranial electrostimulation did not improve cognition and (affective) behavior in patients with probable Alzheimer's disease. In the present study, 21 Alzheimer's disease patients, divided into an experimental (n = 11) and a control group (n = 10), were treated for 30 mins/day, 5 days/wk, for 6 wks with high-frequency cranial electrostimulation. Similar to the previous study, no improvements on cognition and (affective) behavior were found.

Electrical treatment of reduced consciousness: experience with coma and Alzheimer's disease

The right median nerve can be stimulated electrically to help arouse the central nervous system for persons with reduced levels of consciousness. The mechanisms of central action include increased cerebral blood flow and raised levels of dopamine. There is 11 years of experience in the USA of using nerve stimulation for acute coma after traumatic brain injury. There is a much longer period of experience by neurosurgeons in Japan with implanted electrodes on the cervical spinal cord for persons in the persistent vegetative state (PVS). But the use of right median nerve electrical stimulation (RMNS) for patients in the subacute and chronic phases of coma is relatively new. Surface electrical stimulation to treat anoxic brain injury as well as traumatic brain injury is evolving. Novel applications of electrical stimulation in Amsterdam have produced cognitive behavioural effects in persons with early and mid-stage Alzheimer's disease employing transcutaneous electrical nerve stimulation (TENS). Improvements in short-term memory and speech fluency have also been noted. Regardless of the aetiology of the coma or reduced level of awareness, electrical stimulation may serve as a catalyst to enhance central nervous system functions. It remains for the standard treatments and modalities to retrain the injured brain emerging from reduced levels of consciousness.

Repeated 2 Hz peripheral electrical stimulations suppress morphine-induced CPP and improve spatial memory ability in rats

Our previous studies have shown that 2 Hz peripheral electrical stimulation (PES) can suppress morphine-induced conditioned place preference (CPP) in the rat, although the mechanisms remain unclear. Since CPP involves the mechanism of learning and memory, it is rational to ask whether the suppressive effect of repeated 2 Hz PES on morphine-induced CPP is due to an impairment of the function of spatial learning and memory. Rats were trained with 4 mg/kg morphine, i.p. for 4 days to establish the CPP. Twenty-four hours after the CPP testing, they were given PES at 2 Hz once a day for 1, 3 or 5 days, followed by another CPP testing. The results showed that (1) the morphine-induced CPP was significantly inhibited by 3 or 5 consecutive sessions, but not by single session of 2 Hz PES. (2) A test of spatial leaning and memory ability using the Morris water maze task revealed that 2 Hz PES per se exhibited a promoting, rather than a deteriorating effect on the ability of spatial memory. (3) 2 Hz PES by itself produced a moderate yet significant CPP. The results imply that (a) a low frequency PES can produce a rewarding effect as revealed by the CPP testing, which may account, at least in part, for its suppressive effect on morphine induced CPP, (b) the suppressive effect of PES on morphine induced CPP is not due to a deteriorating effect on the ability of spatial memory.

Peripheral electrical stimulation in Alzheimer's disease

In a number of studies, peripheral electrical nerve stimulation has been applied to Alzheimer's disease (AD) patients who lived in a nursing home. Improvements were observed in memory, verbal fluency, affective behavior, activities of daily living and on the rest-activity rhythm and pupillary light reflex. The aim of the present, randomized, placebo-controlled, parallel-group clinical trial was to examine the effects of electrical stimulation on cognition and behavior in AD patients who still live at home. Repeated measures analyses of variance revealed no effects of the intervention in the verum group (n = 32) compared with the placebo group (n = 30) on any of the cognitive and behavioral outcome measures. However, the majority of the patients and the caregivers evaluated the treatment procedure positively, and applying the daily treatment at home caused minimal burden. The lack of treatment effects calls for reconsideration of electrical stimulation as a symptomatic treatment in AD.

Effects of transcutaneous electrical nerve stimulation (TENS) on cognition, behavior, and the rest-activity rhythm in children with attention deficit hyperactivity disorder, combined type

OBJECTIVE

The aim of this study was to examine the effects of transcutaneous electrical nerve stimulation (TENS) on cognition, behavior, and the rest-activity rhythm in children with attention deficit hyperactivity disorder, combined type (ADHD-CT).

METHODS

Twenty-two children diagnosed with ADHD-CT received TENS treatment during 6 weeks, 2 times 30 min a day. Neuropsychological tests were administered to assess cognition, parent/teacher behavioral rating scales were used to measure behavior, and actigraphy was used to assess the rest-activity rhythm.

RESULTS

TENS appeared to have a moderate beneficial influence on cognitive functions that load particularly on executive function. There was also improvement in behavior as measured by parent/teacher behavioral rating scales. Moreover, motor restlessness during sleep and motor activity during the day decreased by TENS.

CONCLUSIONS

The effects of TENS in children with ADHD are modest but encouraging and warrant further research.

Therapeutic strategies for Alzheimer disease: focus on neuronal reactivation of metabolically impaired neurons

Based on several lines of evidence, it has been hypothesized that decreased neuronal metabolic rate may precede cognitive impairment, contributing to neuronal atrophy as well as reduced neuronal function in Alzheimer disease (AD). Additionally, studies have shown that stimulation of neurons through different mechanisms may protect those cells from the deleterious effects of aging and AD, a phenomenon we paraphrased as "use it or lose it." Therefore, it is attractive to direct the development of therapeutic strategies toward stimulation of metabolic rate/neuronal activity to improve cognition and other symptoms in AD. A number of pharmacological and nonpharmacological approaches discussed here support the concept that stimulation of the brain has beneficial effects and may, to a certain degree, restore several aspects of cognition and other central functions. For instance, the circadian system, which controls the sleep/wake cycle, may be stimulated in AD patients by exposing them to more light or transcutaneous nerve stimulation. We will also discuss a procedure that has been developed to culture human postmortem brain tissue, which allows testing of the efficacy of putative stimulatory compounds.

Effects of transcutaneous electrical nerve stimulation (TENS) on non-pain related cognitive and behavioural functioning

An extensive search through nine electronic bibliographic databases (PubMed, Cochrane Library, Web of Science, ERIC, PsychINFO, Psyndex, Cinahl, Biological Abstracts, Rehabdata) was performed in order to review the effects of Transcutaneous Electrical Nerve Stimulation (TENS) on non-pain related cognitive and behavioural functioning. Eight studies were identified on neglect due to stroke, six studies on Alzheimer's disease (AD), one study on aging, and two studies on coma due to traumatic brain injury. The results of the various studies revealed that TENS has a variety of effects. These consist of enhancement of somatosensory functioning, visuo-spatial abilities and postural control in neglect, improved memory, affective behaviour and rest-activity rhythm in AD and acceleration of awakening in coma. Effectiveness of TENS is discussed in relation to various stimulation parameters: duration, frequency, pulse width and intensity. It is argued that arousal may underlie the beneficial influence of TENS in various conditions. Finally, suggestions are offered for future research.

Transcutaneous electrical nerve stimulation (TENS) for dementia

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is the application of an electrical current through electrodes attached to the skin. The commonest clinical application of TENS is pain control. TENS is also used occasionally for the treatment of a range of neurological and psychiatric conditions including drug and alcohol dependence, headaches, and depression. TENS is rarely used for the treatment of dementia. However, since the early 1990s a number of studies carried out by a group in the Netherlands, and one study carried out by a group in Japan, suggest that TENS applied to the back or head may improve cognition and behaviour in patients with Alzheimer's disease or multi-infarct dementia. It was claimed that applying TENS could benefit patients with dementia by altering the activity of various neurotransmitters, or by increasing brain activity and thereby retarding neural degeneration and stimulating regenerative processes. It is claimed that application of TENS to the head may also alleviate the sleep disorders associated with dementia.

OBJECTIVES

The aim of this review is to determine the effectiveness and safety of transcutaneous electrical nerve stimulation (TENS) in the treatment of dementia. Secondary objectives of this review are to determine whether any effect of treatment of dementia with TENS is influenced by any treatment parameters or patient features, including: the duration of treatment, electrical waveform, current amplitude, pulse duration and frequency and the patient's type or severity of cognitive impairment.

SEARCH STRATEGY

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 10 December 2002 using the terms TENS, transcutaneous, "transcutaneous electrical nerve stimulation", and "electric stimulation". The CDCIG Specialized Register contains records from all major health care databases and many ongoing trials databases and is regularly updated.

SELECTION CRITERIA

All RCTs in which TENS was used as an intervention for people with dementia were included in this review. This included peripherally applied transcutaneous electrical stimulation as well as transcutaneous electrical stimulation applied to the head (also known as cranial electrical stimulation (CES)).

DATA COLLECTION AND ANALYSIS

All RCTs that fulfilled the inclusion criteria for the review and for which sufficient data were available were included in this meta-analysis. Two reviewers extracted the data from the included trials. All except one of the included trials used similar outcome measures. Data of the same outcome measures were combined for analysis.

MAIN RESULTS

Eight trials were included in the review but only 3 trials could be included in the meta-analysis. Sufficient data to include the other trials in the meta-analysis could not be obtained. From this limited analysis it appears that TENS produced a statistically significant improvement directly after treatment in: delayed recall of 8 words in one trial, face recognition in two trials and motivation in one trial however, no effect of TENS was found on any of the many other neuropsychological and behavioural measures evaluated either directly after TENS treatment or 6 weeks after treatment was completed.

REVIEWER'S CONCLUSIONS

Although a number of studies suggest that TENS may produce short lived improvements in some neuropsychological or behavioural aspects of dementia, the limited presentation and availability of data from these studies does not allow definite conclusions on the possible benefits of this intervention. Since most of the currently published studies are well designed, although the numbers of subjects in each study is small, analysis of the complete original data from these and/or future studies may allow more definitive conclusions to be drawn.

Brain aging and Alzheimer's disease; use it or lose it

(1) Alzheimer's disease is a multifactorial disease in which age and APOE-epsilon 4 are important risk factors. (2) The neuropathological hallmarks of AD, i.e. amorphous plaques, neuritic plaques (NPs), pretangles, neurofibrillary tangles (NFT) and cell death are not part of a single pathogenetic cascade but may occur independently. (3) In brain areas where classical AD changes, i.e. NPs and NFTs, are present, such as the CA1 area of the hippocampus, the nucleus basalis of Meynert and the tuberomamillary nucleus, a decreased metabolic rate is found. The decreased metabolic rate appears not to be induced by the presence of pretangles, NFT or NPs. (4) Decreased metabolic rate may precede cognitive impairment and is thus an early occurring hallmark of AD, which, in principle, may be reversible. The observation that the administration of glucose or insulin enhances memory in AD patients also supports the view that AD has a metabolic basis. (5) Moreover, several observations in postmortem brain indicate that activated neurons are better able to withstand aging and AD, a phenomenon paraphrased by us as 'use it or lose it'. (6) It is, therefore, attractive to direct the development of therapeutic strategies towards restimulation of neuronal metabolic rate in order to improve cognition and other symptoms in AD. A number of pharmacological and non-pharmacological studies support the concept that activation of the brain has beneficial effects and may, to a certain degree, restore several aspects of cognition and other central functions. For instance, the circadian system may be restimulated in AD patients by exposing them to more light or transcutaneous nerve stimulation. A procedure has been developed to culture human postmortem brain tissue that allows testing of the efficacy of putative stimulatory compounds such as neurotrophins.

Cranial electrostimulation (CES) in patients with probable Alzheimer's disease

In one study, behavioral disorders of patients with vascular dementia reacted positively to cranial electrostimulation (CES). In the present study, it was examined whether CES could improve cognition and (affective) behavior in patients with probable Alzheimer's disease (AD). Eighteen AD patients, divided into an experimental and a placebo group, were treated for 30 min per day, 5 days a week, for 6 weeks. No improvements in cognition and (affective) behavior were found after CES.

Spatial hemineglect in humans

The paper reviews the main findings of studies of hemispatial neglect after acquired brain lesions in people. The behavioral consequences of experimentally induced lesions in animals and electrophysiological studies, which shed light on the nature of the disorder, are briefly considered. Neglect is behaviorally defined as a deficit in processing or responding to sensory stimuli in the contralateral hemispace, a part of the own body, the part of an imagined scene, or may include the failure to act with the contralesional limbs despite intact motor functions. Neglect in humans is frequently encountered after right parieto-temporal lesions and leads to a multicomponent syndrome of sensory, motor and representational deficits. Relevant findings relating to neglect, extinction and unawareness are reviewed and include the following topics: etiological and anatomical basis, recovery; allocentric, egocentric, object-centered and representational neglect; motor neglect and directional hypokinesia; elementary sensorimotor and associated disorders; subdivisions of space and frames of reference; extinction versus neglect; covert processing of information; unawareness of deficits; human and animal models; effects of sensory stimulation and rehabilitation techniques.

Effects of transcutaneous electrical nerve stimulation (TENS) on cognition and behaviour in aging

In previous studies, transcutaneous electrical nerve stimulation (TENS) improved cognition and behaviour in patients with Alzheimer's disease (AD). The rationale underlying these studies was that TENS could activate, e.g. the septo-hippocampal region and the hypothalamus through direct and indirect pathways. As these areas are also affected in normal aging, the present study examined the effects of TENS on cognition and behaviour in nondemented elderly persons. The results suggest an improvement in visual short-term and verbal long-term (recognition) memory, and semantic verbal fluency. Moreover, stimulated elderly persons felt less depressed. Limitations are discussed.

Transcutaneous electrical nerve stimulation (TENS) improves the rest-activity rhythm in midstage Alzheimer's disease

Nightly restlessness in patients with Alzheimer's disease (AD) is probably due to a disorder of circadian rhythms. Transcutaneous electrical nerve stimulation (TENS) was previously reported to increase the strength of coupling of the circadian rest activity rhythm to Zeitgebers in early stage Alzheimer's disease (AD) patients. It was investigated in the present study whether TENS could also improve the rest activity rhythm of patients in a midstage. Sixteen patients who met the NINCDS ADRDA criteria for probable AD, and the stage 6 criteria of the Global Deterioration Scale were treated with TENS or placebo. Rest activity rhythm was assessed using actigraphy. Compared to the control group, stimulated patients showed an improvement in the rest activity rhythm of similar magnitude as observed previously in patients in an early stage. It is concluded that TENS increased the coupling between the rest activity rhythm and supposedly stable Zeitgebers in an advanced stage of AD.

Effects of transcutaneous electrical nerve stimulation on memory and behavior in Alzheimer's disease may be stage-dependent

BACKGROUND

In previous studies, transcutaneous electrical nerve stimulation (TENS) was shown to result in improvements in nonverbal short-term and long-term memory, verbal long-term memory, and verbal fluency in patients in an early stage of Alzheimer's disease (AD). In addition, the patients' physical, social, and affective functioning improved. As AD is a progressive disease, it was examined in the present study whether TENS would still be effective in the midstage of AD.

METHODS

Sixteen subjects (70-91 years old) met the NINCDS-ADRDA criteria for probable AD, as well as the criteria for stage 6 of the Global Deterioration Scale (midstage AD). To evaluate treatment effects, the subjects underwent a number of neuropsychological tests and two observation scales.

RESULTS

Compared to TENS in an early stage, TENS in the midstage of AD appears to yield less beneficial effects, i.e., as for cognition only nonverbal short-term memory improved. No treatment effects were observed for the patients' physical, social, and affective functioning.

CONCLUSIONS

In view of the small number of patients, the clinical relevance of TENS in patients in a midstage of AD remains to be confirmed in a larger group, after which more definite conclusions about the stage-dependency of TENS in AD can be drawn.

Reduced neuronal activity and reactivation in Alzheimer's disease

1. Alzheimer's disease is a multifactorial disease in which age and APOE-epsilon 4 are important risk factors. Various mutations and even viral infections such as herpes simplex (Itzhaki et al., 1997) may play an additional role. 2. The neuropathological hallmarks of Alzheimer's disease (AD), i.e. amorphous plaques, neuritic plaques (NPs), pretangles, neurofibrillary tangles (NFT) and cell death are not part of a single pathogenetic cascade but are basically independent phenomena. 3. Pretangles can occur in neurons from which the metabolic rate is not altered. However, in brain areas where classical AD changes, i.e. NPs and NFTs, are present, such as the CA1 area of the hippocampus, the nucleus basalis of Meynert and the tuberomamillary nucleus, a decreased metabolic rate is found. Decreased metabolic rate appears to be an independent phenomenon in Alzheimer's disease. It is not induced by the presence of pretangles, NFT or NPs. 4. Decreased metabolic rate may precede cognitive impairment and is thus an early occurring hallmark of Alzheimer's disease, which, in principle, may be reversible. The observation that the administration of glucose or insulin enhances memory in Alzheimer patients also supports the view that Alzheimer's disease is basically a metabolic disease. Moreover, several observations indicate that activated neurons are better able to withstand aging and AD, a phenomenon paraphrased by us as "use it or lose it". It is, therefore, attractive to direct the development of therapeutic strategies towards restimulation of neuronal metabolic rate in order to improve cognition and other symptoms in Alzheimer's disease. A number of pharmacological and non-pharmacological studies support the concept that activation of the brain indeed has beneficial effects on several aspects of cognition and other central functions.

Goal Attainment Scaling. A responsive measure of client outcomes

Goal Attainment Scaling (GAS) was developed by Kiresuk and Sherman in 1968. Although highly criticized in the early years of its conception, GAS is beginning to be recognized as a reliable, valid, and responsive outcome measurement approach. This article describes the application of GAS, using elderly home health care clients as an example. Reliability and validity issues are examined. Criticism of GAS is often based on traditional psychometric assumptions associated with normative assessment and does not reflect the evaluative nature of the GAS methodology. The advantages and limitations of GAS are discussed. Goal Attainment Scaling has the potential to demonstrate the important contribution home health care programs make to clients by measuring the change that has occurred during their admission to the program. This kind of information is required by policy makers, case managers, and home health care providers to develop policy, allocate limited resources, and offer appropriate and effective services.

Effects of "isolated" transcutaneous electrical nerve stimulation on memory and affective behavior in patients with probable Alzheimer's disease

BACKGROUND

In previous studies, transcutaneous electrical nerve stimulation (TENS), tactile stimulation, and a combination of the two resulted in cognitive and affective improvements in patients with Alzheimer's disease (AD). As in those studies the therapist was present during the treatment of the experimental and control group (sham stimulation), a positive effect of the combination of TENS with interpersonal communication could not be excluded. Therefore, the effects of "isolated" TENS, i.e., in the absence of the therapist, on memory and affective disturbances in AD patients were examined.

METHODS

Eighteen subjects (78-92 years old) met the NINCDS-ADRDA criteria for the clinical diagnosis of probable AD. To evaluate treatment effects, the experimental group (9) and the control group (9) underwent a number of neuropsychological tests and two observation scales.

RESULTS

Treatment effects were observed for nonverbal short-term (Visual Memory) and long-term (Face Recognition) memory, word fluency (Verbal Fluency), and need of help, whereas patients' affective behavior did not improve.

CONCLUSIONS

The results of the present study show that isolated TENS has a positive effect on patients' cognitive and independent functioning; however, isolated TENS appeared not to have a therapeutic effect on patients' affective behavior.