Grafts of fetal dopamine neurons survive and improve motor function in Parkinson's disease.

Neural transplantation can restore striatal dopaminergic neurotransmission in animal models of Parkinson's disease. It has now been shown that mesencephalic dopamine neurons, obtained from human fetuses of 8 to 9 weeks gestational age, can survive in the human brain and produce marked and sustained symptomatic relief in a patient severely affected with idiopathic Parkinson's disease. The grafts, which were implanted unilaterally into the putamen by stereotactic surgery, restored dopamine synthesis and storage in the grafted area, as assessed by positron emission tomography with 6-L-[18F]fluorodopa. This neurochemical change was accompanied by a therapeutically significant reduction in the patient's severe rigidity and bradykinesia and a marked diminuation of the fluctuations in the patient's condition during optimum medication (the "on-off" phenomenon). The clinical improvement was most marked on the side contralateral to the transplant.

Cognitive function in Parkinson's disease: from description to theory.

From the large body of empirical evidence on cognitive function in Parkinson's disease, a number of attempts have been made to describe the characteristics of the deficits and the conditions under which they are observed. This review considers descriptions limited to specific domains of cognition such as visuospatial function, memory and 'frontal' function, and more general descriptions relating to 'set-shifting', sequencing, temporal ordering and recency discrimination, the locus of cognitive control and bradyphrenia. Later in the paper an attempt is made to provide some theoretical framework for the various descriptions. Two theories are discussed representing contrasting, but complementary approaches. The first is a 'psychological' theory in which the concept of depleted processing resources is suggested as a possible mechanism to explain the observable deficits. The second is a neurobiological model that attempts to integrate information from diverse sources to provide a model for the neuroanatomical and neurochemical substrate that may underlie some of the behavioural deficits.

Writer's cramp.

Writer's cramp has been recognized for over a century, and originally was construed as a physical motor disorder. However, an unfortunate use of the descriptive term 'professional neuroses' to describe this and other similar task-specific conditions, coupled subsequently with fashions in psychiatry, led to the mistaken belief that writer's cramp was due to psychic rather than motor pathology. Evidence has accumulated in recent years showing that writer's cramp is a real focal motor disorder, with a close relation to dystonia. This article summarizes what is known about the aetiology, clinical features, pathophysiology and treatment of writer's cramp and analogous occupational cramps, with the aim of drawing the attention of neuroscientists to this common, bizarre and poorly understood condition.

Investigating associations between biting time in the malaria vector Anopheles arabiensis Patton and single nucleotide polymorphisms in circadian clock genes: support for sub-structure among An. arabiensis in the Kilombero valley of Tanzania.

BACKGROUND: There is growing evidence that the widespread use of Long-Lasting Insecticidal Nets (LLINs) is prompting malaria vectors to shift their biting towards times and places where people are not protected, such as earlier in the evening and/or outdoors. It is uncertain whether these behavioural shifts are due to phenotypic plasticity and/or ecological changes within vector communities that favour more exophilic species, or involve genetic factors within vector species to limit their contact with LLINs. Possibly variation in the time and location of mosquito biting has a genetic basis, but as yet this phenomenon has received little investigation. Here we used a candidate gene approach to investigate whether polymorphisms in selected circadian clock genes could explain variation in the time and location of feeding (indoors versus outside) within a natural population of the major African malaria vector Anopheles arabiensis. METHODS: Host-seeking An. arabiensis were collected from two villages (Lupiro and Sagamaganga) in Tanzania by Human Landing Catch (HLC) technique. Mosquitoes were classified into phenotypes of "early" (7 pm-10 pm) or "late" biting (4 am -7 am), and host-seeking indoors or outdoors. In these samples we genotyped 34 coding SNPs in 8 clock genes (PER, TIM, CLK, CYC, PDP1, VRI, CRY1, and CRY2), and tested for associations between these SNPs and biting phenotypes. SNPs in 8 mitochondrial genes (ATP6, ATP8, COX1, COX2, COX3, ND3, ND5 and CYTB) were also genotyped to test population subdivision within An. arabiensis. RESULTS: The candidate clock genes exhibited polymorphism within An. arabiensis, but it was unrelated to variation in the timing and location of their biting activity. However, there was evidence of strong genetic structure within An. arabiensis populations in association with the TIM, which was unrelated to geographic distance. Substructure within An. arabiensis was also detected using mitochondrial markers. CONCLUSIONS: The variable timing and location of biting in An. arabiensis could not be linked to candidate clock genes that are known to influence behaviour in other Diptera. This finding does not rule out the possibility of a genetic basis to biting behaviour in this malaria vector, but suggests these are complex phenotypes that require more intensive ecological, neuronal and genomic analyses to understand.

Stereotaxic injection of kainic acid into the striatum of rats induces synthesis of mRNA for heat shock protein 70.

Stereotaxic injection of the excitotoxin kainic acid into the striatum of rats has been shown to induce the production of messenger RNA to the 70 kDa heat shock protein. This was evident 2 h after injection and was maximal 24 h after injection of kainic acid. No change in the level of messenger RNA to beta-actin was detected.

Natural history of adult-onset idiopathic torticollis.

The rates of spontaneous remission and progression of dystonia to other sites were studied in 72 patients who first presented with adult-onset torticollis, and who were followed up for a mean of 7.7 years. Dystonia had progressed to sites other than the neck (mainly the face and upper limbs) in 23 patients (32%). The latter cases were not differentiated from those with isolated torticollis in terms of any of the demographic or clinical features studied, although they tended to have suffered from torticollis longer. Fifteen patients (20.8%) had experienced a spontaneous remission of their torticollis, which was sustained for a median period of 3 years in 9 cases (12.5%). Eighty-seven percent of the 15 remissions had occurred during the first 5 years of the illness. In the 9 cases with sustained remission, the duration of torticollis before spontaneous remission was significantly longer and remission had mostly occurred after 2 years of illness compared with the 6 who had relapsed. The 15 cases with spontaneous remission tended to have an earlier age of onset compared with those with no remission. Sixty-five percent of cases were correctly classified on the basis of age at onset, which emerged as the only salient variable in the discrimination of the 15 patients with spontaneous remission from the 57 without spontaneous remission. Age at onset, form of torticollis, gender, and direction of head deviation resulted in a correct classification rate of 70%, in the discrimination of the 9 cases with sustained remission from those with no remission.(ABSTRACT TRUNCATED AT 250 WORDS)

Clonidine in Parkinson disease.

Several theoretical considerations suggest that potentiation of central norepinephrine mechanisms may improve motor performance in patients with Parkinson disease receiving concurrent treatment with levodopa. Clonidine hydrochloride, an antihypertensive drug believed to directly stimulate brain norepinephrine receptors, was administered to a group of patients with relatively mild Parkinson disease and coexisting essential hypertension and to three patients with Parkinson disease manifesting the "on-off" response to levodopa. Although a significant antihypertensive effect was achieved, a change in parkinsonian disability could not be demonstrated.

Sleep spindles in torsion dystonia.

Quantitative analysis of overnight sleep spindles was performed in 14 patients with primary generalized torsion dystonia, 10 patients with secondary torsion dystonia, 10 normal subjects, and 39 patients with other neurological disorders. Only 4 patients with torsion dystonia had increased numbers of sleep spindles, and only one of these had sleep spindles of an abnormal amplitude or duration. Sleep spindle abnormalities do not appear to be common in torsion dystonia, and are unlikely to be of pathophysiological significance in this condition.

Accuracy of self-reported disability in patients with parkinsonism.

For the patient, the most important aspect of parkinsonism is the degree to which the disease interferes with daily living. The patient's self-report may be the only way in which such information can be obtained. Depression and cognitive impairment, however, may influence that self-report. In the present study, three ratings of disability, from the patient, a relative, and an independent observer, showed high levels of agreement. The patients' cognitive function made a small but significant contribution to the accuracy of their self-report judged against the relative's rating. Depression, however, played no role. Agreement between patients and relatives for individual items on the disability questionnaire was reasonably high. The results suggest that patients with parkinsonism can provide accurate self-report of their level of disability, even in the presence of depression and cognitive impairment.

Progressive myoclonic ataxia (the Ramsay Hunt syndrome).

It has been suggested from studies of patients with progressive myoclonus epilepsy that the term Ramsay Hunt syndrome should be abandoned, as its use has led to nosologic confusion, and because, in the light of modern diagnostic techniques, the majority of cases can be allocated to specific disease categories, chiefly, Unverricht-Lundborg disease (Baltic myoclonus) and mitochondrial encephalomyopathy. Review of 30 cases of this syndrome, defined as progressive ataxia and myoclonus and infrequent seizures in the absence of dementia, showed that a clinical or biochemically supported diagnosis could not be made in 43%. This low diagnostic yield probably reflects differences in ascertainment of patients; those described here were referred with a syndrome of progressive myoclonic ataxia (the Ramsay Hunt syndrome) rather than progressive myoclonus epilepsy. These two syndromes share common causes, but a smaller proportion of patients with progressive myoclonic ataxia can currently be diagnosed precisely during life.

The nigrostriatal dopaminergic system assessed in vivo by positron emission tomography in healthy volunteer subjects and patients with Parkinson's disease.

A group of healthy control subjects and patients with Parkinson's disease were investigated using positron emission tomography and two tracers as indicators of different specific properties of the presynaptic dopaminergic system in caudate nucleus and putamen. The first tracer, 6-L-(18F)-fluorodopa, was used as an analog of levodopa to assess its regional brain uptake, conversion into, and retention as dopamine and further metabolites. The second tracer, (11C)-nomifensine was employed as an indicator of striatal monaminergic reuptake sites that are principally dopaminergic. We have used this tracer to assess dopaminergic nerve terminal density. In patients with Parkinson's disease, striatal uptake of both tracers was decreased, putamen being significantly more affected than caudate. Side-to-side differences of uptake in putamen, but not caudate, correlated with corresponding left-right differences of scored clinical motor performance. Both 6-L(18F)-fluorodopa and (11C)-nomifensine tracer uptake in putamen was decreased on average to 40% of normal values, suggesting that a substantial part of the cellular elements of the dopaminergic nigrostriatal system is still intact in living parkinsonian patients. This is in contrast to the generally extreme depletion of endogenous dopamine in the putamen of patients found at postmortem. Our results lend support to the search for drug treatments that protect against further nigrostriatal cell loss and that could be exhibited as soon as the disease manifests clinically. If successful, a sufficient striatal nerve terminal pool would remain so that the effectiveness of levodopa as a dopamine repletor could persist.

The physiology of orthostatic tremor.

This article describes the physiological findings in a patient with orthostatic tremor. The tremor primarily affected the legs, was alternating between antagonist muscle groups, and had a remarkably rapid frequency of 16 Hz. It was present only during certain postures and appeared to be of central origin. A tremor of the same frequency was also recorded in the arms during particular movements, but was cocontracting. We suggest that orthostatic tremor may be generated by spontaneous oscillation in those central structures responsible for organizing the motor programs for standing.

The effect of sleep on the dyskinetic movements of Parkinson's disease, Gilles de la Tourette syndrome, Huntington's disease, and torsion dystonia.

The effect of sleep on the involuntary movements or dyskinesias in Parkinson's disease, Huntington's disease, primary and secondary torsion dystonia, and Gilles de la Tourette syndrome was studied in a total of 52 patients and 10 normal subjects using video electroencephalographic telemetry. Movements typical of the wake pattern were seen occasionally during unequivocal sleep in all but two completed studies, and in each condition reappeared under similar circumstances. The movements were most likely to occur after awakenings or lightenings of sleep, or in stage one sleep. The movements were very rare during the deeper phases of sleep. Those movements that occurred during sleep without awakenings were usually preceded by arousal phenomena and, rarely, by sleep spindles or slow waves. The control group showed normal "semipurposeful" movements under the same conditions during sleep. The rare appearance of the different dyskinesias and normal movements under similar circumstances during sleep could be a result of common effects on the generator systems or changes in the excitability of the final common motor pathway.

The blink reflex in patients with idiopathic torsion dystonia.

The blink reflex and its recovery cycle were examined in 57 patients with idiopathic dystonia affecting different parts of the body. The group comprised 9 patients with generalized and 15 with segmental forms, 19 with torticollis, and 14 with focal arm dystonia. None had blepharospasm. The duration and amplitude of the R2 component of the blink reflex showed only minor changes. However, its recovery cycle to paired supraorbital nerve stimuli was abnormal in all groups of patients, except those with focal arm dystonia. These findings may be interpreted as showing abnormal control of the interneuronal networks mediating the blink reflex in patients with dystonia affecting sites other than the facial muscles. The fact that the principal changes were seen in patients with torticollis, and generalized or segmental dystonia, suggests that the extent of dystonia (rather than the severity) and, therefore, the close proximity to the cranial muscles was important in determining the extent of the abnormal interneuron function.

Clinical presentation and pharmacological therapy in corticobasal degeneration.

BACKGROUND: To date, to our knowledge, there is no systematic presentation of treatment outcome in large series of patients clinically diagnosed as having corticobasal degeneration. OBJECTIVE: To evaluate the clinical presentation and treatment outcome of patients clinically diagnosed as having corticobasal degeneration. SUBJECTS: We gathered case patients seen in 8 major movement disorder clinics during the last 5 years who were diagnosed as having corticobasal ganglionic degeneration. METHODS: Using a chart review method, we recorded the clinical presentation, medications used, response to medications, and adverse effects. RESULTS: A total of 147 case patients were reviewed, 7 were autopsy proven. Parkinsonian features were present in all, other movement disorders in 89%, and higher cortical dysfunction in 93%. The most common parkinsonian sign was rigidity (92%), followed by bradykinesia (80%), gait disorder (80%), and tremor (55%). Other movement disorders were dystonia in 71% and myoclonus in 55%. Higher cortical dysfunction included dyspraxia (82%), alien limb (42%), cortical sensory loss (33%), and dementia (25%). Ninety-two percent of the case patients received dopaminergic drugs, which resulted in a beneficial effect for 24%. Parkinsonian signs were the elements improving the most and levodopa was the most effective drug. Benzodiazepines, primarily clonazepam, were administered to 47 case patients, which resulted in improvement of myoclonus in 23% and dystonia in 9%. The most frequent disabling adverse effects of drug trials in these case patients were somnolence (n = 24), gastrointestinal complaints (n = 23), confusion (n = 16), dizziness (n =12), hallucinations (n = 5), and dry mouth (n = 5). CONCLUSIONS: Pharmacological intervention was largely ineffective in the management of corticobasal degeneration, and new treatments are needed for ameliorating the symptoms of this syndrome.

Cortical reflex myoclonus.

Three patients with a type of myoclonus produced by intention and somatosensory stimulation were studied with electrophysiologic techniques. Each jerk typically affected only a few contiguous muscles; agonist and antagonist muscles were activated simultaneously with a simple electromyographic (EMG) burst lasting 10 to 30 msec. Cranial nerve muscles were activated in an order indicating that the signal to produce the myoclonus traveled down the brainstem. In action-induced jerks a negative transient in the electroencephalogram (EEG) from the contralateral sensorimotor cortex consistently preceded the jerk with a fixed latency. In reflex-induced jerks this negative transient could be recognized as a component of the sensory evoked potential. The types of myoclonus are reviewed and it is argued that this type of myoclonus is mediated in cerebral cortex and that the negative transient represents a paroxysmal depolarization shift (PDS). The myoclonus may result from hyperactivity of a component of the long-latency stretch reflex.

Dystonia in Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy.

Adult-onset dystonia-parkinsonism is a syndrome in search of a pathology. We therefore reviewed the literature on dystonic manifestations in autopsy-proven cases of multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and idiopathic Parkinson's disease (PD). Only 6 of 140 autopsy reports of MSA remarked on the presence of dystonia in life, but personal observations suggest prominent antecollis may develop at some stage in up to 1/2 of sufferers. Similarly, very few (15/118) clinicopathologic observations on PSP included convincing dystonic manifestations, in contrast to some clinical reports where blepharospasm and early limb dystonia were prominent. Virtually any form of focal and segmental dystonia may sometimes occur with clinically diagnosed PD, with occasional descriptions of hemidystonia-hemiparkinsonism. However, there is pathologic confirmation of this diagnosis in only 1 case. With many patients thought clinically to have PD proving pathologically to have another cause for their parkinsonism, the true frequency and the range of dystonic manifestations acceptable in PD remain unknown.

Stretch reflex blepharospasm.

We studied a patient with blepharospasm provoked by stretching the orbicularis oculi muscles. With the eyes closed, EMG of the orbicularis oculi at rest revealed spontaneous rhythmic muscle activity that was not visible. When she tried to open her eyes, repetitive jerking blepharoclonus and tonic blepharospasm rendered her functionally blind. Passive stretching of the orbicularis oculi evoked a burst of EMG activity with two components. Touch or pinprick did not elicit such reflex activity. Anesthesia of the supraorbital nerves abolished muscle responses to stretch and improved the blepharospasm.

Torsion dystonia: a double-blind, prospective trial of high-dosage trihexyphenidyl.

We studied trihexyphenidyl in the treatment of torsion dystonia in a prospective, double-blind crossover protocol. Thirty-one patients completed the protocol. Twenty-two (71%) had a clinically significant response. After a mean follow-up of 2.4 years, 68% of patients continued to take trihexyphenidyl, and 42% continued to show a considerable or dramatic benefit. The 30-mg dose used was generally well tolerated. High-dosage trihexyphenidyl therapy is effective in the management of torsion dystonia.

New insights into the cause of Parkinson's disease.

Current concepts as to the cause of Parkinson's disease (PD) suggest an inherited predisposition to environmental or endogenous toxic agents. Study of the substantia nigra after death in PD has highlighted three major changes: (1) evidence of oxidative stress and depletion of reduced glutathione; (2) high levels of total iron, with reduced ferritin buffering; and (3) mitochondrial complex I deficiency. Which of these is the primary event, generating a secondary cascade of changes culminating in nigral cell death, is unknown. In presymptomatic Lewy body-positive control brains, the nigra shows depletion of reduced glutathione content and, possibly, a reduction of complex I activity. Whatever the significance of these various abnormalities, be they causal or secondary, they provide novel targets for the development of new strategies to treat the cause of PD.