Mental deterioration, visuoperceptive disabilities and constructional apraxia in Parkinson's disease

Parkinson's disease dementia: a neural networks perspective

In the long-term, with progression of the illness, Parkinson's disease dementia affects up to 90% of patients with Parkinson's disease. With increasing life expectancy in western countries, Parkinson's disease dementia is set to become even more prevalent in the future. However, current treatments only give modest symptomatic benefit at best. New treatments are slow in development because unlike the pathological processes underlying the motor deficits of Parkinson's disease, the neural mechanisms underlying the dementing process and its associated cognitive deficits are still poorly understood. Recent insights from neuroscience research have begun to unravel the heterogeneous involvement of several distinct neural networks underlying the cognitive deficits in Parkinson's disease dementia, and their modulation by both dopaminergic and non-dopaminergic transmitter systems in the brain. In this review we collate emerging evidence regarding these distinct brain networks to give a novel perspective on the pathological mechanisms underlying Parkinson's disease dementia, and discuss how this may offer new therapeutic opportunities.

Side and type of motor symptom influence cognition in Parkinson's disease

It is well known that many patients with Parkinson's disease experience neuropsychological decline. However, the nature and extent of mental status change varies widely, with some patients showing mild or no cognitive impairments and others exhibiting frank dementia. Research has shown that several clinical disease parameters may differentially correlate with patterns of neuropsychological dysfunction. The present study examined side and type of motor symptom at disease onset and their relationship to cognition in idiopathic Parkinson's disease (PD). We identified 58 patients who initially presented with one of the following symptom profiles: right-side tremor onset (RSO-T; n = 15), right-side bradykinesia/rigidity onset (n = 12), left-side tremor onset (n = 19), and left-side bradykinesia/rigidity onset (n = 12). There were no differences between groups in disease duration, overall mental status, education, or depression severity. We administered a battery of neuropsychological measures to the four PD subgroups and a group of matched control subjects (n = 40). MANCOVAs controlling for age revealed patients with RSO-T performed significantly better than the other three PD subgroups across the entire neuropsychological battery. Further, the RSO-T subgroup performed comparably to controls. In contrast, the other three PD subgroups showed widespread cognitive deficits. These findings suggest an intricate relationship between motor symptom and side of disease onset and it is the combination of these factors that may influence the disease course and extent of cognitive deterioration. Furthermore, patients who develop tremor on the right side of their body represent a distinct subgroup of PD patients who exhibit relative sparing of cognitive function.

Apraxia in movement disorders

The definition of apraxia specifies that the disturbance of performed skilled movements cannot be explained by the more elemental motor disorders typical of patients with movement disorders. Generally this does not present a significant diagnostic problem when dealing with 'higher-level' praxic disturbances (e.g. ideational apraxia), but it can be a major confound in establishing the presence of limb-kinetic apraxia. Most motor disturbances characteristic of extrapyramidal disorders, particularly bradykinesia and dystonia, will compromise the ability to establish the presence of loss of dexterity and deftness that constitutes this subtype. The term 'apraxia' has also been applied to other motor disturbances, such as 'gait apraxia' and 'apraxia of eyelid opening', that perhaps are misnomers, demonstrating the lack of a coherent nomenclature in this field. Apraxia is a hallmark of corticobasal degeneration (CBD) and historically this has received the most attention among the movement disorders. Corticobasal degeneration is characterized by various forms of apraxia affecting limb function, particularly ideomotor apraxia and limb-kinetic apraxia, although buccofacial and oculomotor apraxia can be present as well. The syndrome of parkinsonism and prominent apraxia, designated the 'corticobasal syndrome' (CBS), may be caused by a variety of other central nervous system pathologies including progressive supranuclear palsy (PSP), Alzheimer's disease, dementia with Lewy bodies and frontotemporal dementias. Distinct from the CBS, PSP and Parkinson's disease can demonstrate varying degrees of apraxia on selected tests, especially in those patients with more severe cognitive dysfunction. Diseases that cause the combination of apraxia and a primary movement disorder most often involve a variety of cerebral cortical sites as well as basal ganglia structures. Clinical-pathological correlates and functional imaging studies are compromised by both this diffuse involvement and the confusion experienced in the clinical evaluation of apraxia in the face of the additional elemental movement disorders. Finally, although apraxia results in clear disability in patients with the CBS, it is not clear how milder ideomotor apraxia found on specific testing contributes to patients' overall day-to-day motor disability.

What causes mental dysfunction in Parkinson's disease?

Parkinson's disease (PD) is frequently associated with mental dysfunction. Domain-specific cognitive deficits are ubiquitous, and although they may not be clinically apparent in all patients, they are demonstrable by neuropsychological testing. Dementia is less frequent but is present significantly more in PD patients than in controls, with a cumulative prevalence rate up to 40% and up to six-fold increased incidence. Cognitive impairment mainly involves executive and visuospatial functions; memory is secondarily impaired with relatively preserved recognition. Qualitatively, the neuropsychological profile of dementia encompasses the same type of deficits found in nondemented PD patients. The dementia seen in PD, therefore, can be described as a dysexecutive syndrome combined with visuospatial dysfunction and behavioural symptoms. Dopaminergic, noradrenergic, serotoninergic, and cholinergic deficits have all been described as the underlying neurochemical impairment, but the strongest evidence exists for a cholinergic dysfunction. Involvement of brainstem nuclei, limbic structures, and cerebral cortex have been suggested as the site, and Lewy body (LB) degeneration and Alzheimer-type changes as the type of pathology underlying the mental dysfunction in PD. Although there is still some controversy as to the site and type of pathology, recent evidence suggests that LB-type degeneration in limbic structures and cerebral cortex, with consequent synaptic and cell loss, is the main pathological state associated with dementia in PD.

Dementia associated with Parkinson's disease

Dementia affects about 40% of patients with Parkinson's disease; the incidence of dementia in these patients is up to six times that in healthy people. Clinically, the prototype of dementia in PD is a dysexecutive syndrome. Loss of cholinergic, dopaminergic, and noradrenergic innervation has been suggested to be the underlying neurochemical deficits. Nigral pathology alone is probably not sufficient for the development of dementia. Although there is some controversy with regard to the site and type of pathology involved, dementia is likely to be associated with the spread of pathology to other subcortical nuclei, the limbic system, and the cerebral cortex. On the basis of more recent studies, the main pathology seems to be Lewy-body-type degeneration with associated cellular and synaptic loss in cortical and limbic structures. Alzheimer's disease-type pathology is commonly associated with dementia but less predictive. Recent evidence from small studies suggests that cholinesterase inhibitors may be effective in the treatment of dementia associated with PD.

Spatial behaviour is driven by proximal cues even in mildly impaired Parkinson's disease

This investigation addresses the question whether patients with mild to moderate Parkinson's disease (PD) show spatial deficits in real-life settings. Therefore, a "search through"-locomotor task incorporating basic features of both the radial arm maze and the Morris water maze paradigms was used. The participants had to find and remember five out of twenty hidden locations within a completely controlled environment. Different spatial memory errors and inter-response intervals were recorded automatically. Fourteen patients with idiopathic PD and fourteen healthy controls matched for age, sex, handedness, and education were investigated. Patients and controls were widely comparable with respect to intelligence, verbal memory, and executive functions. Results show that performance deteriorated in about half of the patients if the starting position was moved by 90 degrees and the proximal cues were deleted simultaneously. This deficit was systematically related to specific measures of attention. Moreover, patients were less able to update their locomotor strategies towards a more effective strategy. Results are discussed with respect to the patient's inability to generate rules which can be flexibly used in changing environments, especially if proximal cues are removed. It is concluded that deficits in spatial behaviour can be elicited even in near-to-real-life situations if appropriate testing procedures are used.

Reversal of the bicycle drawing direction in Parkinson's disease by AC pulsed electromagnetic fields

The Draw-a-Bicycle Test is employed in neuropsychological testing of cognitive skills since the bicycle design is widely known and also because of its complex structure. The Draw-a-Bicycle Test has been administered routinely to patients with Parkinson's disease (PD) and other neurodegenerative disorders to evaluate the effect of transcranial applications of AC pulsed electromagnetic fields (EMFs) in the picotesla flux density on visuoconstructional skills. A seminal observation is reported in 5 medicated PD patients who demonstrated reversal of spontaneous drawing direction of the bicycle after they received a series of transcranial treatments with AC pulsed EMFs. In 3 patients reversal of the bicycle drawing direction was observed shortly after the administration of pulsed EMFs while in 2 patients these changes were observed within a time lag ranging from several weeks to months. All patients also demonstrated a dramatic clinical response to the administration of EMFs. These findings are intriguing because changes in drawing direction do not occur spontaneously in normal individuals as a result of relateralization of cognitive functions. This report suggests that administration of AC pulsed EMFs may induce in some PD patients changes in hemispheric dominance during processing of a visuoconstructional task and that these changes may be predictive of a particularly favourable response to AC pulsed EMFs therapy.

A longitudinal study of visuospatial discrimination in parkinsonian patients

Visuospatial discrimination was evaluated longitudinally in 45 patients with idiopathic Parkinson's disease. 47 normal matched subjects served as controls. Visuospatial discrimination was assessed by means of a picture test with complex superimposed objects (Poppelreuter's test) at the beginning of the study as well as three years later. At initial evaluation the group with Parkinson's disease identified fewer objects than the control group and made more errors. Relations between performance on the visuospatial discrimination task and the main parameters of the disease were not statistically significant. At reevaluation, three years later on the same task, performance by the group with Parkinson's disease deteriorated. Longitudinal assessment of motor symptoms showed that disease progressed during the study period in 35 patients. Comparison of motor deterioration with performance on the visuospatial discrimination task showed no statistically significant relationship.

Reversal of cognitive impairment in an elderly parkinsonian patient by transcranial application of picotesla electromagnetic fields

A 74 year old retired building inspector with a 15 year history of Parkinson's disease (PD) presented with severe resting tremor in the right hand, generalized bradykinesia, difficulties with the initiation of gait with freezing, mental depression and generalized cognitive impairment despite being fully medicated. Testing of constructional abilities employing various drawing tasks demonstrated drawing impairment compatible with severe left hemispheric dysfunction. After receiving two successive transcranial applications, each of 20 minutes duration, with AC pulsed electromagnetic fields (EMFs) of 7.5 picotesla flux density and frequencies of 5Hz and 7Hz respectively, his tremor remitted and there was dramatic improvement in his drawing performance. Additional striking improvements in his drawing performance occurred over the following two days after he continued to receive daily treatments with EMFs. The patient's drawings were subjected to a Reliability Test in which 10 raters reported 100% correct assessment of pre- and post drawings with all possible comparisons (mean 2 = 5.0; p < .05). This case demonstrates in PD rapid reversal of drawing impairment related to left hemispheric dysfunction by brief transcranial applications of AC pulsed picotesla flux density EMFs and suggests that cognitive deficits associated with Parkinsonism, which usually are progressive and unaffected by dopamine replacement therapy, may be partly reversed by administration of these EMFs. Treatment with picotesla EMFs reflects a "cutting edge" approach to the management of cognitive impairment in Parkinsonism.

Treatment with weak electromagnetic fields restores dream recall in a parkinsonian patient

Absent or markedly reduced REM sleep with cessation of dream recall has been documented in numerous neurological disorders associated with subcortical dementia including Parkinson's disease, progressive supranuclear palsy and Huntington's chorea. This report concerns a 69 year old Parkinsonian patient who experienced complete cessation of dreaming since the onset of motor disability 13 years ago. Long term treatment with levodopa and dopamine (DA) receptor agonists (bromocriptine and pergolide mesylate) did not affect dream recall. However, dreaming was restored after the patient received three treatment sessions with AC pulsed picotesla range electromagnetic fields (EMFs) applied extracranially over three successive days. Six months later, during which time the patient received 3 additional treatment sessions with EMFs, he reported dreaming vividly with intense colored visual imagery almost every night with some of the dreams having sexual content. In addition, he began to experience hypnagogic imagery prior to the onset of sleep. Cessation of dream recall has been associated with right hemispheric dysfunction and its restoration by treatment with EMFs points to right hemispheric activation, which is supported by improvement in this patient's visual memory known to be subserved by the right temporal lobe. Moreover, since DA neurons activate REM sleep mechanisms and facilitate dream recall, it appears that application of EMFs enhanced DA activity in the mesolimbic system which has been implicated in dream recall. Also, since administration of pineal melatonin has been reported to induce vivid dreams with intense colored visual imagery in normal subjects and narcoleptic patients, it is suggested that enhanced nocturnal melatonin secretion was associated with restoration of dream recall in this patient. These findings demonstrate that unlike chronic levodopa therapy, intermittent pulsed applications of AC picotesla EMFs may induce in Parkinsonism reactivation of reticular-limbic-pineal systems involved in the generation of dreaming.

Brief communication: electromagnetic fields improve visuospatial performance and reverse agraphia in a parkinsonian patient

A 73 year old right-handed man, diagnosed with Parkinson's disease (PD) in 1982, presented with chief complaints of disabling resting and postural tremors in the right hand, generalized bradykinesia and rigidity, difficulties with the initiation of gait, freezing of gait, and mild dementia despite being fully medicated. On neuropsychological testing the Bicycle Drawing Test showed cognitive impairment compatible with bitemporal and frontal lobe dysfunction and on attempts to sign his name he exhibited agraphia. After receiving two successive treatments, each of 20 minutes duration, with AC pulsed electromagnetic fields (EMFs) of 7.5 picotesla intensity and 5 Hz frequency sinusoidal wave, his drawing to command showed improvement in visuospatial performance and his signature became legible. One week later, after receiving two additional successive treatments with these EMFs each of 20 minutes duration with a 7 Hz frequency sinusoidal wave, he drew a much larger, detailed and visuospatially organized bicycle and his signature had normalized. Simultaneously, there was marked improvement in Parkinsonian motor symptoms with almost complete resolution of the tremors, start hesitation and freezing of gait. This case demonstrates the dramatic beneficial effects of AC pulsed picotesla EMFs on neurocognitive processes subserved by the temporal and frontal lobes in Parkinsonism and suggest that the dementia of Parkinsonism may be partly reversible.

Meta-analytic comparison of the components of visual cognition in Parkinson's disease

Controversy surrounds the presence of deficits of visual cognition in Parkinson's Disease. This literature has been seriously undermined by a number of methodological and theoretical faults that make interpretation of this hypothesis difficult. This review proposes a structure of visual cognition composed of 13 aspects. A meta-analysis of these components on 70 studies that used standardised neuropsychological tests and an appropriate normal control group indicates that the PD subjects are significantly compromised on tests of attention and concentration, complex visuospatial functions, and multifactorial spatial functions. More detailed analysis of the basic components of visual cognition was not undertaken due to low statistical power; hence, it remains unclear whether these subjects have primary visual processing deficits in association with their higher order deficits. The observed deficits may be interpreted as being a consequence of either undetermined lower level visual cognitive deficits or a compromise in executive functioning.

Improvement of body image perception in Parkinson's disease by treatment with weak electromagnetic fields

Neuropsychological studies have demonstrated that Parkinson's disease (PD) is associated with various cognitive deficits ultimately leading in about 30% of patients to the development of dementia. These studies have demonstrated also a greater decrement of right hemispheric functions which are manifested by visuospatial deficits occurring in up to 90% of PD patients. The Human Figure Drawing Test has been employed in the assessment of generalized intellectual deterioration and specifically in the evaluation of visuperceptive, visuospatial and visuoconstructional abilities in brain injured patients. I have demonstrated recently, on the basis of various drawing tests, that external application of electromagnetic fields (EMFs) in the picotesla (pT) range intensity improved visuoperceptive and visuospatial functions in Parkinsonian patients. In the present communication I present 4 fully medicated nondemented Parkinsonian patients who were administered the Human Figure Drawing Test before and after a series of treatments with EMFs. The Human Figure Drawing Test was selected for the study specifically since it was shown to be sensitive to the effects of surgery to the basal ganglia in Parkinsonian patients. Prior to application of EMFs these patients' drawings showed distortion, poor perspective, impoverished facial expression, and lack of attention to details suggested poor body image perception related to right posterior hemispheric dysfunction. In response to the administration of EMFs the group demonstrated a striking improvement in the drawings particularly the depiction of the face the perception of which is localized to the right parietal lobe. These findings demonstrate that treatment with pT EMFs improves body image perception in Parkinsonian patients, a deficit which may remain unaffected by treatment with standard dopaminergic pharmacotherapy.

Reversal of visuospatial deficit on the Clock Drawing Test in Parkinson's disease by treatment with weak electromagnetic fields

Visuospatial deficits are among the most frequently encountered abnormalities in neuropsychological testing of patients with Parkinson's disease, being present in up to 90% of cases. Clinically, impairment of visuospatial functions may not be noted by Parkinsonian patients but may contribute to various functional disabilities including frequent falls, difficulties operating a vehicle, ambulating, and dressing. I have reported recently that treatment with external electromagnetic fields (EMFs) in the picotesla (pT) range intensity is an effective nonpharmacological modality in the management of the motor and various cognitive deficits of Parkinsonism including visuoperceptive and visuospatial functions. The present communication concerns four fully medicated Parkinsonian patients who, in response to treatment with EMFs, exhibited reversal of visuospatial impairments as demonstrated on the Clock Drawing Test. Specifically, prior to treatment with EMFs these patients demonstrated a visuospatial deficit which was evident by the placement of the numbers on the clock distant from the periphery. Following a series of treatments with EMFs this visuospatial deficit was corrected. The report supports prior observations demonstrating that externally applied pT range intensity EMFs may bring about reversal of visuospatial deficits in Parkinsonian patients which usually are not improved by treatment with dopaminergic or anticholinergic drugs.

Aging and memory: corrections for age, sex and education for three widely used memory tests

The associate learning subtest from the Wechsler Memory Scale; Benton's Visual Retention test and a Controlled Word Association Task (FAS) were administered to a random sample of normal, healthy individuals whose age ranged from 20 to 79 years, recruited within the Italian peninsula. The neuropsychological examination took place on a mobile unit and the tests were given by the same team of neuropsychologists to reduce variability among examiners. The Research Project was known as Progetto Memoria. Corrections to the scores of these tests were calculated for age, sex, and education. These corrected values will allow clinicians to screen for memory impairment with greater precision among normally aging individuals, thus improving differential diagnosis between physiologic and pathologic deterioration of cognitive functions.

Improvement in short-term visual memory by weak electromagnetic fields in Parkinson's disease

Neuropsychological studies have demonstrated that Parkinson's disease (PD) is associated with various cognitive deficits ultimately leading in about 30% of patients to the development of dementia. These studies have demonstrated also a greater decrement of right hemispheric functions with visuospatial deficits occurring in up to 90% of PD patients. The Rey-Osterrieth Complex Figure (ROCF) Test has been employed in the assessment of right hemispheric functions and particularly for the evaluation of visuoconstructive abilities and short-term visual memory. I have demonstrated recently that external application of electromagnetic fields (EMFs) in the picotesla (pT) range intensity is an effective nonpharmacological modality in the management of the motor and cognitive deficits of Parkinsonism. In the present communication I present 3 fully medicated nondemented PD patients (mean age: 68 +/- 8.1 yrs; mean duration of illness: 9.0 +/- 4.0 yrs; mean disability on the Hoehn and Yahr scale: 3) who were tested on the ROCF Test before and after a series of treatments with EMFs. In response to the administration of EMFs the group demonstrated a mean of 23.1 +/- 13.6% improved performance on copy of the ROCF and a 39.3 +/- 13.4% improvement of short-term recall of the ROCF. These findings demonstrate that treatment with pT EMFs improves deficits in visuospatial functions and visual memory in Parkinsonism which usually remain unaffected during standard treatment with dopaminergic pharmacotherapy.

Weak electromagnetic fields reverse visuospatial hemi-inattention in Parkinson's disease

Drawing tasks, both free and copied, have achieved a central position in neuropsychological testing of patients with unilateral cerebral dysfunction by virtue of their sensitivity to different kinds of organic brain disorders and their ability to provide information on lateralized brain damage. In the drawings of patients with right hemispheric damage, visuospatial neglect is revealed by the omission of details on the side of the drawing contralateral to the hemispheric lesion. Patients with unilateral cerebral damage, particularly those with left hemispheric damage, also demonstrate a tendency to place their drawings on the side of the page ipsilateral to the cerebral lesion, a phenomenon which has been termed visuospatial hemi-inattention. It has been reported previously that brief external application of alternating pulsed electromagnetic fields (EMFs) in the picotesla (pT) range intensity improved visuoperceptive and visuospatial functions and reversed neglect in Parkinsonian patients. The present communication concerns four fully medicated elderly nondemented Parkinsonian patients (mean age: 74.7 +/- 4.6 yrs; mean duration of illness: 7.7 +/- 5.2 yrs) in whom application of these EMFs produced reversal of visuospatial hemi-inattention related to left hemispheric dysfunction. These findings support prior observations demonstrating that pT EMFs may bring about reversal of certain cognitive deficits in Parkinsonian patients.

Reduced visuospatial performance in children with the D2 dopamine receptor A1 allele

Previous studies suggest a reduced dopaminergic function in subjects with the A1 (minor) allele of the D2 dopamine receptor (DRD2) gene. To explore influences on visuospatial ability as a function of the DRD2 gene, 182 alcohol- and other drug-naive sons (age 10-14) of active alcoholic, recovered alcoholic, and nonalcoholic fathers were administered a visuospatial task (Benton's Judgment of Line Orientation Test) which makes minimal motoric/verbal demands. Visuospatial scores were lower for boys with the A1 allele and for sons of active alcoholics. A1-allele boys made more errors than A2 boys on all 11 of the template lines, with the effect being largest for the rightmost presentations. In contrast, the effect of family history for alcoholism was strongest on both right and left midquadrant presentations. Moreover, separate analyses of the two types of errors produced allele but not family history of alcoholism effects when the two lines were misjudged as farther apart than they actually were and family history but not allele effects where the two lines were misjudged as closer together. These results suggest that polymorphism of the DRD2 gene and family history of alcoholism are dissociable determinants of visuospatial ability and that visuospatial defects previously observed in alcoholics may, in part, be antecedent to their drinking behavior.

Reversal of a visuoconstructional deficit in Parkinson's disease by application of external magnetic fields: a report of five cases

Visuoperceptive and visuomotor deficits are among the most frequently encountered abnormalities in neuropsychological testing of patients with Parkinson's disease, being present in up to 90% of cases. Clinically, the presence of visuoperceptive and visuomotor impairment may not be noted by Parkinsonian patients but may contribute to various functional disabilities including difficulties operating a vehicle, ambulating, and dressing. The present communication concerns five medicated Parkinsonian patients who responded to extracranial treatment with magnetic fields in the picotesia range intensity with improvement in motor, behavioral, and autonomic functions as well as visuoconstructional tasks as demonstrated on the Bicycle Drawing test. Specifically, prior to treatment with magnetic fields these patients failed to draw the spokes in the wheels of a bicycle that extended completely to the periphery of the rim. I considered this observation to reflect a specific visuoconstructional deficit inherent to the Parkinsonian disease process. This visuoconstructional impairment was reversed, however, by external applications of magnetic fields. The report supports prior observations demonstrating that picotesla range intensity magnetic fields may bring about reversal of specific cognitive deficits in Parkinsonian patients.

The effects of picoTesla range magnetic fields on perceptual organization and visual memory in parkinsonism

Drawing tasks, both free and copied, have achieved a central position in the neuropsychological evaluation of constructional abilities in brain injured patients. The Rey-Osterrieth Complex Figure Test was devised in early 1940s as a tool to investigate perceptual organization and visual memory. The Bicycle Drawing Test is used as a measure of mechanical reasoning as well as visuographic functioning. Recent reports have demonstrated that extracranial treatment with magnetic fields (MF) in the picoTesla range improves constructional abilities including visuoperceptive functions in Parkinsonian patients. To evaluate further the effects of these extremely weak MF on cognitive functions in Parkinsonism, I investigated in a 69 year old fully medicated Parkinsonian patient the influence of a single, extracranial application of MF on the patient's performance on the Complex Figure (copy and recall) as well as the Bicycle Drawing Test. Results of the trial showed that a 30 minute application of MF produced a dramatic improvement in the patient's ability to copy and recall the Complex Figure. This treatment was also associated with a marked improvement in the performance of bicycle drawing with reversal of the Parkinsonian micrographia. Collectively, these findings demonstrate that this treatment modality may reverse some of the cognitive impairments associated with Parkinsonism which usually are not improved by treatment with dopaminergic or anticholinergic medications.

Reversal of visual neglect in Parkinson's disease by treatment with picoTesla range magnetic fields

Visual neglect and impairment in perceptual motor or visuospatial tasks are among the most frequently encountered abnormalities in neuropsychological testing of patients with Parkinson's disease, being present in up to 90% of patients. It has been proposed that neglect reflects an attentional-arousal deficit induced by lesions that interrupt a cortical-limbic-reticular loop. Recently, we have reported that application of extracranial magnetic fields (MF) in the picoTesla range was efficacious in reducing the severity of the motor disability of Parkinsonism as well as improving some of the cognitive abnormalities associated with the disease such as visuoperceptive deficits. We now present a 61 year old fully medicated Parkinsonian patient in whom rapid reversal of left visual neglect as well as improvement in visuoconstructional (drawing) performance was noted immediately after a single external application of MF. We propose that this effect was related to enhancement of directed attention through a mechanism involving an interaction between the pineal gland, which is considered a "magnetosensor," and the reticular formation which mediates arousal and attention. This report demonstrates the efficacy of extremely weak MF in reversing some of the cognitive abnormalities in Parkinsonism, notably neglect and visuoperceptive deficits, which contribute significantly to impairment of the patient's daily living activities.

Rapid improvement of visuoperceptive functions by picoTesla range magnetic fields in patients with Parkinson's disease

Impairment in perceptual motor or visuospatial tasks is among the most frequently encountered abnormality in neuropsychological testing of patients with Parkinson's disease, being present in up to 90% of cases. Visuoperceptive deficits can result from cortical and subcortical lesions involving the right hemisphere, thalamus, and basal ganglia and are thought to reflect a defect in attentional-arousal mechanisms induced by lesions that interrupt a cortical-limbic-reticular activating loop. Clinically, the presence of visuoperceptive impairment may not be noted by Parkinsonian patients but may contribute to various disabilities including difficulty driving a vehicle and difficulties performing daily tasks which require intact visuospatial abilities (i.e., walking, dressing, drawing and copying designs). The present communication concerns two fully medicated Parkinsonian patients who responded to extracranial treatment with picoTesla range magnetic fields (MF), behaviorally and also demonstrated rapidly and dramatically enhanced visuoperceptive functions as demonstrated on various drawing tasks. These findings demonstrate the efficacy of extremely weak MF in enhancing cognitive functions in patients with Parkinson's disease.

The relationship between visuospatial ability and perceptual motor function in Parkinson's disease

To assess the contribution of visuoperceptual function to complex visuomotor responding in Parkinson's disease, 14 patients with idiopathic PD and 12 normal controls matched for age, education and general intellectual function were administered a visual tracing task. No difference was found between the groups on two visuoperceptual tests, the Benton Line Orientation test and a test of trajectory judgement. However, patients were significantly impaired in tracing a sawtooth design when two consecutive angles of the sawtooth were occluded. This impairment occurred in reproducing the basic form of the stimulus and not with accuracy of fine detail. These results suggest higher-order perceptual motor dysfunction independent of any breakdown in basic visuoperceptual processing or loss of fine motor control. It is concluded that Parkinsonian patients are unable to use sensory information accurately to plan and execute complex or new movements.

Visuospatial working memory in Parkinson's disease

Visuospatial impairment is frequently reported in Parkinson's disease but the psychological mechanisms which subserve the impaired abilities and the way in which breakdown of the mechanisms leads to performance deficits have not been precisely delineated. This paper reports experimental investigations designed to test the hypothesis that the locus of the impairment is the visuospatial subsystem of working memory. Subjects were a group of sixteen patients with Parkinson's disease of mild to moderate severity and a matched control group. They performed complex visuospatial and verbal memory tasks. The Parkinsonian group were significantly slower than the control group when performing the visuospatial task. They were not significantly slower and made no more errors than the control group on the verbal task. The findings are compatible with the hypothesis that the visuospatial subsystem of working memory is impaired in Parkinson's disease. It is demonstrated that the impairment is not the result of a reduction in the capacity of this subsystem but is due to difficulty in utilising information stored in the subsystem to perform complex visuospatial tasks.

The neuropsychology of de novo patients with idiopathic Parkinson's disease: the effects of age of onset

One hundred de novo patients with Parkinson's disease (PD) were classified into two groups according to age of onset of symptoms. Seventy two patients were under 70 years and 28 were 70 years and over. All patients were given neurological and neuropsychological assessments, and the severity of the signs was rated on a modified Columbia scale. The neuropsychological assessment was also administered to 50 age-and-education-matched controls. The neuropsychological test battery included tests of verbal learning, visual memory, verbal fluency, visuospatial skill, simple and choice reaction time, language and maze learning. The late-onset patients had significant impairment in nonverbal reasoning, auditory verbal learning, visual memory and choice reaction time in contrast to early-onset patients and controls. A relationship was found between bradykinesia and widespread cognitive impairment. Severity of tremor was found to be significantly correlated with impairment in auditory verbal learning, visual memory and increased choice reaction time, while rigidity was found to be associated with cognitive impairment in verbal fluency and visuospatial skill. Using DSM II criteria, 39% of the late-onset and 8% of the early-onset group were classified as demented. Dementia was more common in patients with bilateral symmetrical disease and in those patients with marked tremor and bradykinesia. The pattern of cognitive impairment in PD was consistent with that associated with a subcortical dementia. This study confirms that the expression of PD is markedly influenced by the age of onset.

Parkinson's disease: a conceptualization of neuropsychological deficits within an information-processing framework

Parkinson's disease patients are frequently impaired in a variety of neuropsychological tasks involving memory, perceptual motor performance and cognitive flexibility. Although various theories have been forwarded to explain specific impairments, few attempts have been made to account for all the deficits within a single theoretical framework. Furthermore, the frequent occurrence of dementia, the adverse side effects of medication and the motor symptoms of the disease tend to interfere with neuropsychological performance. This has hindered the clear delineation of the neuropsychological profile of Parkinsonian patients. The present paper examines the evidence for intellectual deficits in non-demented Parkinson's disease patients. A number of problems inherent in cognitive research on Parkinson's disease are discussed. The contribution of dementia, motor symptom severity and medication in the expression of these intellectual impairments is examined. It is suggested that many of the neuropsychological deficits described in Parkinson's disease may result from a common underlying deficit in some aspect of information processing. Although it is not possible to pinpoint the precise mechanism(s) involved on the basis of the available evidence, several possibilities are suggested by cognitive and electrophysiological data.

Changes in the performance of parkinsonian patients and normal aged on the Benton Visual Retention Test

Performance on the Benton Visual Retention Test was compared between those with Parkinson's disease (PD) and age-equivalent controls. The major difference between groups was that those with PD showed an increase in figural reproduction errors between test periods spaced six months apart, while controls showed little increase in errors over this time and made fewer errors at each time of testing. Age and IQ accounted for major proportions of variance in performance for both groups (about 50%), far more than that attributable to group membership. Within the PD group, however, age and disease onset were confounded (r = .92), indicating that age as a variable is quite when disease onset is considered. The results support the notion that PD is associated with change in visual-spatial memory, beyond that predicted by age per se.

Visuo-spatial processing in parkinsonians

It has been suggested that patients with Parkinson's disease (PDs) may have problems processing visuo-spatial information and that this deficiency may contribute to the motor control problems observed in PD. However, most studies reporting visuo-spatial deficits are equivocal; they confound perceptual and motor processes. To address this issue, the present experiment systematically compared the relative contributions of several cognitive processes to performance: perception, stimulus-response translation, movement preparation and execution. Seven non-demented PDs and seven age-matched controls performed visual RT tasks, based upon judgements of spatial displacements. Both the RT and MT data suggested that PDs do not prepare movements as adequately as normals, and that PD deficits are associated with problems controlling movement execution. On the other hand, PDs were not slower in judging distances and linking perception to action, suggesting that previous findings of visuo-spatial deficits may be due in part to motor impairments.

Intellectual impairment in Parkinson's disease: clinical, pathologic, and biochemical correlates

The prevalence of overt dementia in 27 studies representing 4,336 Parkinson's disease (PD) patients was 39.9%. The studies reporting the highest incidence of intellectual impairment (69.9%) used psychologic assessment techniques, whereas studies identifying the lowest prevalence of dementia (30.2%) depended on nonstandardized clinical examinations. Neuropsychologic investigations reveal that PD patients manifest impairment in memory, visuospatial skills, and set aptitude. Language function is largely spared. Intellectual deterioration in PD correlates with age, akinesia, duration, and treatment status. Neuropathologic and neurochemical observations demonstrate that PD is a heterogeneous disorder: the classic subcortical pathology with dopamine deficiency may be complicated by atrophy of nucleus basalis and superimposed cortical cholinergic deficits, and a few patients have the histopathologic hallmarks of Alzheimer's disease. Mild intellectual loss occurs with the classic pathology, and the more severe dementia syndromes have cholinergic alterations or Alzheimer's disease. Thus, PD includes several syndromes of intellectual impairment with variable pathologic and neurochemical correlates.

Review: drug induced akathisia in medical and surgical patients

Drug-induced akathisia is a significant and common iatrogenic disorder. It involves both a subjective component of a disturbing sense of compulsion to move and an objective component of motor restlessness. Akathisia is being seen with increasing frequency in medical and surgical patients. This is due to the increased use of anti-emetics or novel adjuncts to pain control as well as more widespread use of the major psychoactive drugs throughout medicine. This review focuses on diagnostic features of the disorder as well as on possible treatment approaches. In addition, the disorder demonstrates the close anatomic and functional relationship between cortical and subcortical dopaminergic pathways. Akathisia is thus both an increasingly significant clinical problem and a fascinating glimpse at the relationship between brain function and behavior.

Visuoperception and visuospatial and visuorotational performance in Parkinson's disease

Forty patients with Parkinson's disease were compared with 33 normal controls with respect to their performance in the Wechsler Adult Intelligence Scale subtests "information", "similarities", "block design", and "picture completion", in a test for visual neglect (Hamsher's line cancellation test) and in tests for visuospatial and visuorotational abilities (cube task from Amthauer's intelligence structure test and Rybakoff figure test, as revised by Meili). The findings show that the patients scored significantly worse than the controls (Mann-Whitney U test, P = 0.004) in the Rybakoff figure test, testing visual concept finding, imagination and visual rotation. In the other tests no significant differences were found between the patients and the controls. The deficit of the patients in the figure test of Rybakoff correlated significantly with tremor (P = 0.013), akinesia (P = 0.009), disability (P = 0.043), and age (P = 0.004, Spearman rank correlation).

A model for the assessment of eating problems in patients with Parkinson's disease

A model for the assessment of eating problems in patients with Parkinson's disease was constructed on the basis of literature about eating and Parkinson's disease. The model is based on the World Health Organization's classification of disabilities and handicaps and on the Erikson theory of 'eight stages of man'.

[Neuropsychological dysfunctions in Parkinson's disease: a study of 64 cases]

Sixty-four cases of idiopathic Parkinson's disease were studied focusing the neuropsychological performance. To all subjects a brief mental status questionnaire was administered (30 items). Cases with a performance below normal and meeting the dementia criteria of the Diagnosis and Statistical Manual of Mental Disorders, third edition (DSM III), were considered demented. This evaluation showed that 12 of the 64 patients had dementia, a prevalence rate of 18.7%. Patients that had neuropsychological performance below normal showed more severe bradykinesia than normals. Short term memory, abstract thinking, visual gnosia, calculations, dynamic motor function of hands, constructional ability and recent memory were the most affected psychological functions. The significance of the mentioned findings is discussed and the literature reviewed.

Is there a specific visuo-spatial impairment in Parkinsonians?

Twenty-five non-demented patients with mild, idiopathic, Parkinson's disease were compared with 25 age and education matched normal controls on a visuo-spatial performance task, whose characteristics were directional forecast, with minimal motor requirement and a maximal spatial load. No statistical support was found for the existence of spatial impairment in these patients.

Dementia in movement disorders

Of all the movement disorders, Huntington's disease has been most consistently associated with dementia, while it is only over the last decade that intellectual cognitive decline have been recognized as common features of Parkinson's disease. It is now known that the pathology in these two conditions reflects differential involvement of the striatum. The Huntington lesion is primarily in the caudate, while the Parkinson lesion preferentially affects the putamen. Both conditions have more diffuse pathology, and dementia may also occur in a wide range of other extrapyramidal diseases, such as progressive supranuclear palsy, the parkinsonism-dementia complex of Guam, and certain spinocerebellar degenerations. Clinicopathological correlations will be reviewed in these disorders of primarily subcortical pathology, and comparisons will be made with Alzheimer's disease, a disorder of predominantly cortical pathology.

Cognitive performance in early Parkinson's disease

The cognitive, memory and psychomotor performance of 67 patients with Parkinson's disease who had not received any antiparkinson medication was compared with the performance of 43 healthy subjects matched by age and education. The principal impairments in the patients were motor ones, evident in various tests such as general motor slowness and delayed initiation of movement, and they correlated with clinical rigidity and hypokinesia but not with tremor. The performance of the patients was inferior to that of the controls in memory tests involving the processing of information and learning (logical memory, associative learning) but not in less demanding tasks such as the retrieval of numbers. The total disability was due to a combined effect of aging and disease. A decrease of about 15% in the psychomotor and cognitive performance, related to aging alone, can be expected to occur between the ages of 50 and 70. The performance of the patients in memory tests and other tests evaluating cognitive capacity did not correlate either with their motor disability or with their mood. A possibility therefore exists that biological processes behind the cognitive decline and the motor disability are separate, even if they may occur simultaneously.

The concept of subcortical and cortical dementia: another look

The subcortical dementias such as progressive supranuclear palsy, Huntington's disease, and Parkinson's disease are said to be characterized by the presence of slowed mentation, apathy, and the absence of aphasia, agnosia, and apraxia, symptoms that are claimed to be more common in cortical dementias such as Alzheimer's disease. Conceptual problems (such as vagueness of terms and difficulties with symptom definition) and methodological problems (such as improper matching of comparison groups and inadequate assessment techniques) found in currently available studies require a reappraisal of this classification of dementias into cortical and subcortical forms. A review of recent clinical, neuropathological, and neurochemical studies offers little support for this classification system, although adequate systematic studies have not been performed.

Does unilateral dopamine deficit contribute to depression?

A system of emotional control of behavior is believed to be lateralized to the right hemisphere. Given that dopaminergic pathways are involved in affective behavior, depression, which is recognized as an integral part of Parkinson's disease, may be associated with a dopamine imbalance. The present study examined this hypothesis in patients with unilateral symptomatology indicating either left hemisphere parkinsonism (LHP) or right hemisphere parkinsonism (RHP). Sixteen patients were tested on a battery of neuropsychological tests and several scales for evaluating mood. The two groups did not differ significantly on either cognitive or emotional measures. However, RHP patients rated themselves higher on the Present Scale of Cantril, and showed some neglect of the left visual field, as compared to LHP patients.