Mobile phone use facilitates memory in male,but not female,subjects

In the present study we report on the effects of mobile phone exposure on short- and long-term memory in male and female subjects. Subjects were university undergraduate students, and consisted of right-handed, males (n = 33) and females (n = 29). Individuals were randomly assigned to one of three experimental conditions: no phone exposure; inactive phone exposure; and active phone exposure. They were provided with a series of words to learn, structured in a two-dimensional shape, and given 3 min to memorise the words. After a 12 min distraction task, they were then asked to draw the shape (spatial) and place the correct words (semantic) into the appropriate boxes. One week later the same subjects were brought back to again redraw the shape and words. Error scores were determined and analysed by non-parametric techniques. The results show that males exposed to an active phone made fewer spatial errors than those exposed to an active phone condition, while females were largely unaffected. These results further indicate that mobile phone exposure has functional consequences for human subjects, and these effects appear to be sex-dependent.     

Disordered integration of heteromodal short-term cognitive operations: A breakdown of working memory

Abstract

We report a patient with bilateral frontal lobe infarcts with a symptom that has not yet been documented in the literature. He complained of severe difficulty in making a phone call. On examination, he demonstrated extreme difficulty in pointing to a series of numbers, although he had normal vision, normal motor and sensory functions, fair auditory memory for numbers and memory for spatial span. Based on a number of tests, we concluded that the patient's principal disorder was difficulty in converting one mode of information into another mode of information. This unexpected symptom can be best explained in terms of a working memory paradigm. Although individual modal systems, or slave systems, retained nearly normal function, simultaneous holding of heteromodal information and its modal transformation in the central executive system seemed to have been at fault.     

Shift in sound localization induced by rTMS of the posterior parietal lobe

Neuroimaging studies in human subjects and single-unit recordings in monkeys have suggested the primate posterior parietal cortex (PPC) to be involved in auditory space perception. Here we tested this hypothesis by combining repetitive focal transcranial magnetic stimulation (rTMS) of the right PPC with a task of pointing to free-field-sound stimuli. After a period of 15 min rTMS at 1Hz, subjects exhibited an overall signed error in pointing by 2.5 degrees, directed to the left and downward, with reference to a baseline condition with "sham rTMS". No effects of rTMS on the general precision of sound localization (unsigned errors) were found. Thus, low-frequency offline rTMS may have specifically affected neuronal circuits transforming auditory spatial coordinates in both azimuth and elevation. This is in accordance with the view that the PPC may represent a neural substrate of the perceptual stability in spatial hearing.     

The acute effects of exposure to the electromagnetic field emitted by mobile phones on human attention

The aim of our study was to investigate the effects of acute mobile phone exposure on a range of tasks which tapped capacity and processing speed within the attentional system. Thirty-eight healthy volunteers were randomly assigned to either an experimental group which was exposed to a connected mobile phone or a control group in which the mobile phone was switched off. Subjects remained blind to mobile phone status throughout duration of study. The experimental group were exposed to an electromagnetic field emitted by a 900 MHz mobile phone for 30 min. Cognitive performance was assessed at three points (prior to mobile phone exposure, at 15 and 30 min post-exposure) using six cognitive neuropsychological tests (digit span and spatial span forwards and backwards, serial subtraction and verbal fluency). Significant differences between the two groups were evident after 5 min on two tests of attentional capacity (digit span forwards and spatial span backwards) and one of processing speed (serial subtraction). In all three instances, performance was facilitated following mobile phone exposure. No deficits were evident. These findings are discussed in terms of possible functional and neuroanatomical bases.     

Behavior and memory evaluation of Wistar rats exposed to 1·8 GHz radiofrequency electromagnetic radiation

Abstract

Background:

The development of communication systems has brought great social and economic benefits to society. As mobile phone use has become widespread, concerns have emerged regarding the potential adverse effects of radiofrequency electromagnetic radiation (RF-EMR) used by these devices.

Objective:

To verify potential effects of mobile phone radiation on the central nervous system (CNS) in an animal model.

Methods:

Male Wistar rats (60 days old) were exposed to RF-EMR from a Global System for Mobile (GSM) cell phone (1·8 GHz) for 3 days. At the end of the exposure, the following behavioral tests were performed: open field and object recognition.

Results:

Our results showed that exposed animals did not present anxiety patterns or working memory impairment, but stress behavior actions were observed.

Conclusion:

Given the results of the present study, we speculate that RF-EMR does not promote CNS impairment, but suggest that it may lead to stressful behavioral patterns.     

Mobile interventions for severe mental illness: design and preliminary data from three approaches

Mobile devices can be used to deliver psychosocial interventions, yet there is little prior application in severe mental illness. We provide the rationale, design, and preliminary data from 3 ongoing clinical trials of mobile interventions developed for bipolar disorder or schizophrenia. Project 1 used a personal digital assistant to prompt engagement in personalized self-management behaviors based on real-time data. Project 2 employed experience sampling through text messages to facilitate case management. Project 3 was built on group functional skills training for schizophrenia by incorporating between-session mobile phone contacts with therapists. Preliminary findings were of minimal participant attrition, and no broken devices; yet, several operational and technical barriers needed to be addressed. Adherence was similar to that reported in nonpsychiatric populations, with high participant satisfaction. Therefore, mobile devices seem feasible and acceptable in augmenting psychosocial interventions for severe mental illness, with future research in establishing efficacy, cost effectiveness, and ethical and safety protocols.     

Effects of electromagnetic radiation on spatial memory and synapses in rat hippocampal CA1

In this study,we investigated the effects of mobile phone radiation on spatial learning,reference memory,and morphology in related brain regions.After the near-field radiation(0.52-1.08 W/kg) was delivered to 8-week-old Wistar rats 2 hours per day for 1 month,behavioral changes were examined using the Morris water maze.Compared with the sham-irradiated rats,the irradiated rats exhibited impaired performance.Morphological changes were investigated by examining synaptic ultrastructural changes in the hippocampus.Using the physical dissector technique,the number of pyramidal neurons,the synaptic profiles,and the length of postsynaptic densities in the CA1 region were quantified stereologically.The morphological changes included mitochondrial degenerations,fewer synapses,and shorter postsynaptic densities in the radiated rats.These findings indicate that mobile phone radiation can significantly impair spatial learning and reference memory and induce morphological changes in the hippocampal CA1 region.     

Gender differences in the use of external landmarks versus spatial representations updated by self-motion

Numerous data in the literature provide evidence for gender differences in spatial orientation. In particular, it has been suggested that spatial representations of large-scale environments are more accurate in terms of metric information in men than in women but are richer in landmark information in women than in men. One explanatory hypothesis is that men and women differ in terms of navigational processes they used in daily life. The present study investigated this hypothesis by distinguishing two navigational processes: spatial updating by self-motion and landmark-based orientation. Subjects were asked to perform a pointing task in three experimental conditions, which differed in terms of reliability of the external landmarks that could be used. Two groups of subjects were distinguished, a mobile group and an immobile group, in which spatial updating of environmental locations did not have the same degree of importance for the correct performance of the pointing task. We found that men readily relied on an internal egocentric representation of where landmarks were expected to be in order to perform the pointing task, a representation that could be updated during self-motion (spatial updating). In contrast, women seemed to take their bearings more readily on the basis of the stable landmarks of the external world. We suggest that this gender difference in spatial orientation is not due to differences in information processing abilities but rather due to the differences in higher level strategies.     

Effects of instructional set on amnesic recognition memory performance

Tests that tapped memory for spatial location, temporal order, frequency of occurrence, and category membership were administered to a group of alcoholic Korsakoff patients, a group of mixed amnesic patients with primarily temporal lobe pathology, and a group of normal subjects. The four tests were administered with incidental as well as intentional learning conditions. All groups performed better in the intentional than the incidental condition of the category recognition test. None of the groups performed better in the intentional than the incidental conditions on any of the other tests. The data were interpreted as implying that amnesic patients do not benefit from intentional learning conditions in tests of memory for contextual stimuli.     

The effects of the intraamygdalar melatonin injections on the anxiety like behavior and the spatial memory performance in male Wistar rats

In the present study, the effects of intraamygdalar administrations of melatonin (1 and 100 μg/kg), saline and diazepam on the anxiety-like behavior and spatial memory performance in pinealectomized and sham-pinealectomized Wistar rats were investigated. The animals were tested by open field and elevated plus maze tests for anxiety-like behavior, and Morris water maze test for spatial memory. In open field, (a) diazepam was more effective in reducing the anxiety, (b) control subjects were more mobile than pinealectomized subjects and (c) 100 μg/kg melatonin administrations reduced the velocity of the animals. In elevated plus maze, (a) 100 μg/kg melatonin administrations increased the distance totally travelled and (b) enhanced the time spent in open arms, however, after the pinealectomy, 1 μg/kg melatonin administrations decreased it and (c) control animals were less mobile than pinealectomized ones. In Morris water maze, (a) diazepam group travelled more distance than the others in control condition whereas, in pinealectomy condition high dose of melatonin and saline groups travelled more distance than the others, (b) in pinealectomy condition subjects who received 100 μg/kg melatonin also travelled more distance than those who received 1 μg/kg melatonin and diazepam, (c) the subjects who received 1 μg/kg spent less time than those who received other treatments, and (d) in control condition subjects who received 100 μg/kg melatonin were slower than those who received the other treatments. In conclusion, melatonin administration to amygdala decreased the anxiety; however, spatial memory performance of the rats was impaired by the pinealectomy and melatonin administrations.     

Memory, attention, and executive function in chronic fatigue syndrome.

OBJECTIVES--To examine cognitive function in chronic fatigue syndrome. METHODS--Twenty patients with chronic fatigue syndrome recruited from primary care and 20 matched normal controls were given CANTAB computerised tests of visuospatial memory, attention, and executive function, and verbal tests of letter and category fluency and word association learning. RESULTS: Patients with chronic fatigue syndrome were impaired, predominantly in the domain of memory but their pattern of performance was unlike that of patients with amnesic syndrome or dementia. They were normal on tests of spatial pattern recognition memory, simultaneous and delayed matching to sample, and pattern-location association learning. They were impaired on tests of spatial span, spatial working memory, and a selective reminding condition of the pattern-location association learning test. An executive test of planning was normal. In an attentional test, eight subjects with chronic fatigue syndrome were unable to learn a response set; the remainder exhibited no impairment in the executive set shifting phase of the test. Patients with chronic fatigue syndrome were also impaired on verbal tests of unrelated word association learning and letter fluency. CONCLUSION--Patients with chronic fatigue syndrome have reduced attentional capacity resulting in impaired performance on effortful tasks requiring planned or self ordered generation of responses from memory.     

Effects of a 902 MHz mobile phone on cerebral blood flow in humans: a PET study

Fourteen healthy right-handed subjects were scanned using PET with a [15O]water tracer during exposure to electromagnetic field (EMF) emitted by a mobile phone and a sham-exposure under double-blind conditions. During scanning, the subjects performed a visual working memory task. Exposure to an active mobile phone produced a relative decrease in regional cerebral blood flow (rCBF) bilaterally in the auditory cortex but no rCBF changes were observed in the area of maximum EMF. It is possible that these remote findings were caused by the EMF emitted by the active mobile phone. A more likely interpretation of the present findings were a result of an auditory signal from the active mobile phone. Therefore, it is not reasoned to attribute this finding to the EMF emitted by the phone. Further study on human rCBF during exposure to EMF of a mobile phone is needed.     

Is memory impairment greater than cognitive impairment in moderate chronic alcoholics?

The aims of the research were to test (i) whether moderate chronic alcoholics (A/pts) perform worse than non teetotaler controls (C/pts) either on memory or on intelligence tasks or on both, and (ii) whether there was a significant difference between verbal and spatial memory scores pointing to the claimed prevailing right hemisphere sensitivity to alcohol abuse. Great care was taken in selecting C/pts not to exaggerate by sample biasing the psychological effects of alcoholism. Intelligence was tested by means of verbal and performance Wechsler-Bellevue IQ and Raven PM47; memory was tested by means of serial immediate memory span and learning by means of verbal and spatial devices. The results support the conclusion that chronic wine alcoholism in a band of drinkers with lowish educational background and very set drinking habits impairs memory and intelligence without any significant difference. Moreover there is no evidence of a prevalent right hemisphere sensitivity to chronic alcohol addiction.     

Remote Ecological Momentary Testing of Learning and Memory in Adults With Serious Mental Illness

Smartphone-based ecological mobile cognitive tests (EMCTs) can measure cognitive abilities in the real world, complementing traditional neuropsychological assessments. We evaluated the validity of an EMCT of recognition memory designed for use with people with serious mental illness, as well as relevant contextual influences on performance. Participants with schizophrenia (SZ), schizoaffective disorder, and bipolar disorder (BD) completed in-lab assessments of memory (Hopkins Verbal Learning Test, HVLT), other cognitive abilities, functional capacity, and symptoms, followed by 30 days of EMCTs during which they completed our Mobile Variable Difficulty List Memory Test (VLMT) once every other day (3 trials per session). List length on the VLMT altered between 6, 12, and 18 items. On average, participants completed 75.3% of EMCTs. Overall performance on VLMT 12 and 18 items was positively correlated with HVLT (ρ = 0.52, P < .001). People with BD performed better on the VLMT than people with SZ. Intraindividual variability on the VLMT was more specifically associated with HVLT than nonmemory tests and not associated with symptoms. Performance during experienced distraction, low effort, and out of the home location was reduced yet still correlated with the in-lab HVLT. The VLMT converged with in-lab memory assessment, demonstrating variability within person and by different contexts. Ambulatory cognitive testing on participants’ personal mobile devices offers more a cost-effective and “ecologically valid” measurement of real-world cognitive performance.     

Retrograde amnesia for autobiographical memories and public events in mild and moderate Alzheimer's disease

Patients with mild to moderate Alzheimer's disease and normal controls were tested on two retrograde memory tests, one based on public events, and the other querying autobiographical memory. On both tests, patients showed strong decrements as compared to normal controls, pointing to retrograde amnesia. Evidence for a gradient in retrograde amnesia was conflicted, with analyses of variance revealing no gradient beyond the most recent period, and more sensitive analyses pointing to shallow Ribot gradients on both tests. A literature review shows that this is the case in most published studies. In autobiographical remote memory patients generated many incorrect answers, a tendency correlated with the number of false alarms on an anterograde memory test administered several months earlier. This suggests a stable, possibly executive, factor underlying memory errors.     

Working memory deficit as a core neuropsychological dysfunction in schizophrenia

OBJECTIVE: This study tested the hypothesis that impaired working memory is a core deficit underlying multiple neuropsychological deficits in schizophrenia patients. METHOD: The subjects were 27 men with stable chronic schizophrenia treated with atypical antipsychotics and 38 normal participants. They were assessed with a battery of neuropsychological tests. Verbal working memory was measured with the WAIS digit span tests, and the Dot Test was used to test spatial working memory. RESULTS: In the patients, verbal working memory showed significant correlations with visual retention, visual orientation, simple motor function, visuomotor coordination, and executive function but not with memory for objects, memory for faces, recognition of facial emotions, or attention. Spatial working memory showed significant correlations with visual retention, visual orientation, memory for objects, memory for faces, and simple motor function but not attention, executive function, or visuomotor coordination. In the comparison group, no correlations between working memory and other neuropsychological functions were found. CONCLUSIONS: These findings support the hypothesis that working memory is a core deficit in schizophrenia. The authors postulate that the lower capacity for verbal and spatial "on-line storage" is rate limiting in the performance of other cognitive functions. Executive functions rely critically on the phonetic loop, complex visual functions such as object and face memory rely on the spatial on-line storage system (visuospatial scratch pad), while other functions such as visual orientation depend critically on both capacities.     

An evaluation of cognitive disorders after anterior choroidal artery infarction

Anterior choroidal artery infarction (AChAI) can be the source of aphasia and spatial neglect, but we have no idea of the other possible cognitive disorders. Here, we investigated these disorders in a relatively large cohort of AChAI patients. Twenty patients with relatively recent infarction (left side: 13; mean delay = 47.4 days; 10 men; mean age = 59.6; mean education level, EL = 10.3) were included. We assessed nonspatial attention (alertness, Go Nogo, divided attention and visual vigilance from the computerized test TEA), spatial attention (bell test), language (BDAE) orientation (time, place), short-term memory (forward and backward digit spans, spatial span), executive functioning (WCST, TMT A and B, categorial evocation), delayed memory (Buschke verbal test, Rey figure test), and retrograde memory (questionnaire on famous events). The performance level was compared with that of 20 control subjects matched in age and EL. AChAI patients were impaired in several tests of attention (slowness, increase in omission and error rate), executive functioning (TMT B; categorical evocation) and delayed memory. Conversely, we found preservation of spatial attention, language, orientation, short-term memory, WCST, and retrograde memory. In conclusion, at the secondary phase post-stroke, these patients can present with moderate disorders of attention, memory and executive functioning, which are clearly less severe than what is usually observed following thalamic or cortical lesions.     

Effects of long-term electromagnetic field exposure on spatial learning and memory in rats

With the development of communications industry, mobile phone plays an important role in daily life. Whether or not the electromagnetic radiation emitted by mobile phone causes any adverse effects on brain function has become of a great concern. This paper investigated the effect of electromagnetic field on spatial learning and memory in rats. 32 trained Wistar rats were divided into two groups: exposure group and control group. The exposure group was exposed to 916 MHz, 10w/m2 mobile phone electromagnetic field (EMF) 6 h a day, 5 days a week, 10 weeks. The completion time, number of total errors and the neuron discharge signals were recorded while the rats were searching for food in an eight-arm radial maze at every weekend. The neuron signals of one exposed rat and one control rat in the maze were obtained by the implanted microelectrode arrays in their hippocampal regions. It can be seen that during the weeks 4–5 of the experiment, the average completion time and error rate of the exposure group were longer and larger than that of control group (p < 0.05). During the weeks 1–3 and 6–9, they were close to each other. The hippocampal neurons showed irregular firing patterns and more spikes with shorter interspike interval during the whole experiment period. It indicates that the 916 MHz EMF influence learning and memory in rats to some extent in a period during exposure, and the rats can adapt to long-term EMF exposure.     

Navigational Experience and the Preservation of Spatial Abilities into Old Age Among a Tropical Forager-Farmer Population

Navigational performance responds to navigational challenges, and both decline with age in Western populations as older people become less mobile. But mobility does not decline everywhere; Tsimané forager-farmers in Bolivia remain highly mobile throughout adulthood, traveling frequently by foot and dugout canoe for subsistence and social visitation. We, therefore, measured both natural mobility and navigational performance in 305 Tsimané adults, to assess differences with age and to test whether greater mobility was related to better navigational performance across the lifespan. Daily mobility was measured by GPS tracking, regional mobility through interview, navigational performance through pointing accuracy and perspective taking in environmental space, and mental rotation by a computerized task. Although mental rotation and spatial perspective taking declined with age, mobility and pointing accuracy remained high from mid-life through old age. Greater regional mobility was associated with greater accuracy at pointing and perspective taking, suggesting that spatial experience at environmental scales may help maintain navigational performance in later adulthood.     

Effects of haloperidol on recall and information processing in verbal and spatial learning

1. Normal male subjects were tested with either a multi-trial word list learning test or a spatial analogue prior to administration of either 4 mg. or 10 mg. of oral haloperidol. Six hours after drug administration subjects who had previously received the verbal test were administered the spatial test, and vice versa, so for each test there was a no-drug control group, a group tested after receiving 4 mg. of haloperidol, and a group tested after a 10 mg. dose. 2. Both the verbal and spatial learning tests yield multidimensional measures of components of memory and learning, including measures sensitive to effort-demanding and more automatic information processing operations. 3. Results showed no differences for either test among the pre-drug control group and the 4 mg. and 10 mg. groups, with only one minor exception. 4. The lack of significant results cannot be attributed to insensitivity of the test instruments used, since previous studies have documented sensitivity to a number of clinical conditions and to aging. 5. Results have implications regarding clinical effects of haloperidol. A theory that links dopaminergic functioning with effortful information processing underlying memory and learning was not supported.