Improved language performance in Alzheimer disease following brain stimulation

OBJECTIVES

Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a possible treatment for the cognitive deficits associated with Alzheimer disease (AD). The aim of this study was to assess the long-term effects, on cognitive performance, of rTMS applied to the left dorsolateral prefrontal cortex (DLPFC) in AD patients.

METHODS

Ten AD patients were randomly assigned to one of two study groups. Multiple-baseline design was used.The first group underwent a 4-week real rTMS stimulation protocol, while the second underwent a 2-week placebo treatment, followed by 2 weeks of real rTMS stimulation. Each session consisted of the application of rhythmic high-frequency rTMS over the DLPFC for 25 min. Sessions occurred once daily, 5 days/week. The main analysed outcome was the change in cognitive test performance at 2 and 4 weeks after rTMS treatment initiation, with a follow-up performed 8 weeks after the end of rTMS, in comparison with baseline performance.

RESULTS

A significant difference was found between groups over sessions in terms of the percentage of correct responses of auditory sentence comprehension. Only real treatment induced an improvement in performance with respect to baseline or placebo. Moreover, both groups showed a lasting effect on the improved performance 8 weeks after the end of treatment.

CONCLUSION

The findings provide initial evidence for the persistent beneficial effects of rTMS on sentence comprehension in AD patients. Rhythmic rTMS, in conjunction with other therapeutic interventions, may represent a novel approach to the treatment of language dysfunction in AD patients.

Action and Object Naming in Physiological Aging: An rTMS Study

Word-retrieval difficulties commonly occur in healthy aging. Recent studies report an improved ability to name pictures after the administration of high-frequency repetitive transcranial magnetic stimulation (rTMS) in healthy younger adults and in patients with neurological disease. The aim of this study was to assess the effect of high-frequency rTMS applied to the dorsolateral prefrontal cortex (DLPFC) on picture naming in healthy older adults. High-frequency rTMS was applied to the left and right DLPFC during object and action naming in 13 healthy older adults. The naming latency for actions was shortened after stimulation of the left and right DLPFC compared to application of the sham stimulation. Stimulation was not observed to have any effect on correctness of naming. Our data demonstrate the involvement of the left and right DLPFC in a sample of healthy aging subjects during an action-naming task. The bilateral involvement of the DLPFC in these participants is discussed together with data on younger adults and on Alzheimer's patients.

Metabolic compensation and depression in Alzheimer's disease

BACKGROUND/AIMS

The aim of this study was to map metabolic compensation and depression in Alzheimer's disease (AD) on a voxel-by-voxel basis.

METHODS

Twenty-one healthy elderly subjects and 25 AD patients underwent cerebral MR and FDG-PET imaging. All images were processed with SPM2, and whole-brain gray matter (GM) atrophy and hypometabolism maps were computed. Metabolic compensation and depression were assessed using Biological Parametric Mapping software.

RESULTS

GM atrophy and hypometabolism mapped to similar regions, with varying degrees of severity. Significant metabolic compensation was found in the amygdala, while exceeding hypometabolism was mainly located in the posterior cingulate cortex.

CONCLUSION

Metabolic depression can be due to both distant effects of atrophy and to additional hypometabolism-inducing factors, such as amyloid deposition. Conversely, metabolic compensation could reflect spared synaptic plasticity of the surviving neurons. The investigation of the metabolic compensation mechanism could help in the comprehension of the AD underlying pathology.

The role of the dorsolateral prefrontal cortex in retrieval from long-term memory depends on strategies: a repetitive transcranial magnetic stimulation study

The ability to associate a name to a face is a crucially relevant task in daily life. In this study, we investigated the neuronal basis of face-name retrieval in young subjects using repetitive transcranial magnetic stimulation (rTMS) over the left or right dorsolateral prefrontal cortex (DLPFC). The experimental task was composed of two study phases: an encoding phase and a retrieval phase. During the encoding phase, subjects saw a face (familiar or unfamiliar) followed by a name. During the retrieval phase, they saw the face together with two names and had to choose the name that was correctly associated with the face. rTMS was delivered only during retrieval. In addition, we evaluated the use of memory strategies during the task. Accordingly, subjects were subdivided into two groups: strategy users (SU) and no-strategy users (NSU). No rTMS effects were present for familiar face-name pairs, probably due to a ceiling effect. However, for unfamiliar face-name pairs, the different use of memory strategies resulted in different rTMS effects. The SU group showed a selective interference effect after right DLPFC stimulation, whereas the NSU group showed an effect after left DLPFC stimulation. Importantly, the overall performance of the two groups was comparable. We suggest that during memory retrieval the left DLPFC might be recruited when the subject does not apply deliberately a retrieval strategy whereas there is a shift to the right DLPFC if cognitive control processes that are engaged by strategies are needed to guide episodic retrieval.

Naming facilitation induced by transcranial direct current stimulation

Transcranial direct current stimulation (tDCS) is able to generate a long-term increase or decrease in the neuronal excitability that can modulate cognitive tasks, similar to repetitive transcranial magnetic stimulation. The aim of this study was to explore the effects of tDCS on a language task in young healthy subjects. Anodal, cathodal and sham tDCS were applied to the left dorsolateral prefrontal cortex (DLPFC) before two picture naming experiments, a preliminary study (i.e., experiment 1) and a main study (i.e., experiment 2). The results show that anodal tDCS of the left DLPFC improves naming performance, speeding up verbal reaction times after the end of the stimulation, whereas cathodal stimulation had no effect. We hypothesize that the cerebral network dedicated to lexical retrieval processing is facilitated by anodal tDCS to the left DLPFC. Although the mechanisms responsible for facilitation are not yet clear, the results presented herein implicate a facilitation lasting beyond the end of the stimulation that imply cortical plasticity mechanisms. The opportunity to non-invasively interact with the functioning of these plasticity mechanisms will surely open new and promising scenarios in language studies in basic and clinical neuroscience fields.

In vivo neuropathology of cortical changes in elderly persons with schizophrenia

BACKGROUND

Elderly schizophrenia patients frequently develop cognitive impairment of unclear etiology. Magnetic resonance imaging (MRI) studies revealed brain structural abnormalities, but the pattern of cortical gray matter (GM) volume and its relationship with cognitive and behavioral symptoms are unknown.

METHODS

Magnetic resonance scans were taken from elderly schizophrenia patients (n = 20, age 67 +/- 6 SD, Mini-Mental State Examination [MMSE] 23 +/- 4), Alzheimer's disease (AD) patients (n = 20, age 73 +/- 9, MMSE 22 +/- 4), and healthy elders (n = 20, age 73 +/- 8, MMSE 29 +/- 1). Patients were assessed with a comprehensive neuropsychological and behavioral battery. Cortical pattern matching and a region-of-interest analysis, based on Brodmann areas (BAs), were used to map three-dimensional (3-D) profiles of differences in patterns of gray matter volume among groups.

RESULTS

Schizophrenia patients had 10% and 11% lower total left and right GM volume than healthy elders (p < .001) and 7% and 5% more than AD patients (p = .06 and ns). Regions that had both significantly less gray matter than control subjects and gray matter volume as low as AD mapped to the cingulate gyrus and orbitofrontal cortex (BA 30, 23, 24, 32, 25, 11). The strongest correlate of gray matter volume in elderly schizophrenia patients, although nonsignificant, was the positive symptom subscale of the Positive and Negative Syndrome Scale, mapping to the right anterior cingulate area (r = .42, p = .06).

CONCLUSIONS

The orbitofrontal/cingulate region had low gray matter volume in elderly schizophrenia patients. Neither cognitive impairment nor psychiatric symptoms were significantly associated with structural differences, even if positive symptoms tended to be associated with increased gray matter volume in this area.

Dementia, delusions and seizures: storage disease or genetic AD?

We describe a case of a young patient suffering from a rapidly progressive cognitive decline, associated with delusions, myoclonus and seizures and with no family history for dementia. Clinical features, along with skin biopsy findings were overlapping storage disease; the genetic analysis, however, demonstrated a de novo presenilin 1 mutation. The present report suggests the usefulness of genetic determinations in early-onset cases of dementia, even without an autosomal dominant trait of inheritance; for these cases and their relatives an extensive genetic counselling should be recommended.

The Frontal Behavioural Inventory (Italian version) differentiates frontotemporal lobar degeneration variants from Alzheimer's disease

The objective was to evaluate the construct validity of the Italian version of the Frontal Behavioural Inventory (FBI) and its usefulness in the differential diagnosis of dementias. Standard criteria were used in the clinical diagnosis of dementias in 83 patients and 33 agematched healthy volunteers. The FBI scale was translated from English into Italian language and back-translated. Cronbach's alpha, inter-rater and test-retest reliability, FBI convergent validity and discriminant analysis were calculated. FBI profile was compared between patients affected by frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD). The FBI showed a high internal consistency and inter-rater reliability and it distinguished normal behavioural conditions from those presented in FTLD or AD. An 86.8% diagnostic accuracy was calculated by the discriminant analysis, selecting only age at disease onset and FBI, and particularly distinguishing behavioural variants within the FTLD spectrum. FTLD patients showed a characteristic behavioural profile. The FBI might be a reliable and useful diagnostic tool for dementias in clinical practice.

Universal grammar in the frontotemporal dementia spectrum: evidence of a selective disorder in the corticobasal degeneration syndrome

INTRODUCTION

While sentence comprehension has been reported to be defective in frontotemporal dementia (FTD), it is still unclear if this disorder reflects the presence of syntactic impairment, or may be attributed to other factors, such as executive or working memory dysfunction. In order to assess the status of syntactic knowledge in a group of patients belonging to the FTD spectrum, we investigated their ability to detect violations of Universal Grammar principles in a sentence judgement task.

METHODS

The group included four semantic dementia patients (SD), nine frontal variant of FTD patients (FvFTD), 15 progressive supranuclear palsy (PSP) patients, and 11 corticobasal degeneration syndrome (CBDS) patients. Their performance was compared to a group of 10 patients with mild probable Alzheimer disease (AD) and to 10 healthy volunteers. The patients underwent a standard aphasia test and a sentence comprehension test. The experimental study included five kinds of violations: semantic coherence (SC), verb-subject agreement (VSAgr), pronominalization involving clitic movement (ClM), interrogatives (WhS) and contrastive focus constructions (CFC).

RESULTS

The FTD patients performed within normal range in the aphasia test, and in the sentence comprehension test. Within the FTD subgroups, only patients with CBDS were significantly impaired in detecting three of the five kinds of violations. AD patients were also impaired in the detection of WhS and SC anomalies and in sentence comprehension.

DISCUSSION

The present findings indicate that, within the FTD spectrum, an impairment of syntactic knowledge can be found only in CBDS patients, even in the absence of clinical evidence of aphasia.

Action and object naming in Parkinson's disease without dementia

The present study aimed to assess the ability in objects and actions naming in Parkinson's disease (PD) patients. Further, we wished to assess the effect of a particular conceptual dimension, i.e. manipulability, on the naming of object and actions. Patients were recruited from the Department of Neurology, University of Brescia. Thirty-two were diagnosed as PD, according to published criteria, and 15 healthy volunteers matched in age and education to patients' sample. All patients underwent a detailed clinical and neurological evaluation. The stimuli used in the action-object picture naming task were taken from the Center for Research in Language-International Picture Naming Project corpus. To assess the effect of manipulability (or the involvement of fine hand movements) the noun-verb stimuli were re-categorized into manipulable and non-manipulable items (i.e. objects which can or cannot be manipulated and actions which do or do not involve fine hand movements). Patients showed a deficit both in action and object naming, compared with controls. In addition, patients with PD but not controls were significantly more impaired in action than in object naming. The current study supports the view that action naming is affected in patients with PD, possibly reflecting the presence of prefrontal dysfunction.

Persistent autobiographical amnesia: a case report

We describe a 47-year-old man who referred to the Emergency Department for sudden global amnesia and left mild motor impairment in the setting of increased arterial blood pressure. The acute episode resolved within 24 hours. Despite general recovery and the apparent transitory nature of the event, a persistent selective impairment in recollecting events from some specific topics of his personal life became apparent. Complete neuropsychological tests one week after the acute onset and 2 months later demonstrated a clear retrograde memory deficit contrasting with the preservation of anterograde memory and learning abilities. One year later, the autobiographical memory deficit was unmodified, except for what had been re-learnt. Brain MRI was normal while H20 brain PET scans demonstrated hypometabolism in the right globus pallidus and putamen after 2 weeks from onset, which was no longer present one year later. The absence of a clear pathomechanism underlying focal amnesia lead us to consider this case as an example of functional retrograde amnesia.

Cognitive impairment in adult myotonic dystrophies: a longitudinal study

The clinical relevance and extent of cognitive impairment in adult myotonic dystrophy type 1 (DM1) and 2 (DM2) is still unclear. The aim of this study was to determine whether previously reported cognitive abnormalities progress over time and if this occurs in DM2 as it does in DM1. Fifty-six patients with DM1 and 29 patients with DM2 were subjected to muscle strength assessment, and to a complete battery of neuropsychological tests. Repeated assessment was performed in 20 DM1 and 13 DM2 over time (DM1 mean follow-up: 7.3+/-2.7 years; DM2 mean follow- up: 9.5+/-2.4 years). Muscle strength and test scores for frontal lobe functions worsened significantly over time (p<0.01), in both DM1 and DM2. DM2 is a progressive muscle disorder, although less severe than DM1. In both DM1 and DM2 frontal cognitive impairment (attentional) worsens over time but does not extend to additional areas of cognition.

Effect of Transcranial Magnetic Stimulation on Action Naming in Patients With Alzheimer Disease

OBJECTIVE

To assess the effect of repetitive transcranial magnetic stimulation (rTMS) to the dorsolateral prefrontal cortex (DLPFC) on picture naming in patients with Alzheimer disease (AD).

DESIGN

Experimental study. Patients with AD underwent rTMS in real and control conditions during picture-naming tasks.

SETTING

San Giovanni di Dio Fatebenefratelli Scientific Institute in Brescia, Italy. Patients Fifteen patients with probable AD. Intervention High-frequency rTMS was applied to the left and right DLPFC during object and action naming.

MAIN OUTCOME MEASURES

Language ability was assessed by accuracy of verbal response during online rTMS.

RESULTS

Stimulation to the left and right DLPFC improved accuracy in action naming.

CONCLUSIONS

These findings indicate that rTMS to the DLPFC, which speeds up action naming in normal controls, improves performance in patients with AD. While the mechanisms of rTMS-induced naming facilitation in these patients are unknown, the procedure may be worth testing as a novel approach to the treatment of language dysfunction.

Cognitive rehabilitation in Alzheimer's Disease

Non-pharmacological treatment in Alzheimer's Disease has gained great attention in recent years. The limited efficacy of drug therapy and the plasticity of human central nervous system are the two main reasons that explain this growing interest in rehabilitation. Different approaches have been developed. Here we discuss the efficacy of non-pharmacological therapy in the frame of two main approaches: Multistrategy Approaches (Reality Orientation, Reminiscence Therapy and Validation Therapy) and Cognitive Methods.