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PubMed2005

Normalized perfusion MRI to identify common areas of dysfunction: patients with basal ganglia neglect.

Perfusion-weighted imaging (PWI) is used to identify brain regions that are receiving enough blood supply to remain structurally intact, but not enough to function normally. Previous observations suggest that spatial neglect due to subcortical stroke can be explained by dysfunction of cortical areas rather than through the neuronal loss in the subcortical structures itself. The present study aimed to identify the dysfunctional cortical regions induced by basal ganglia stroke in patients with spatial neglect. In a patient group with stroke lesions centring on the basal ganglia, we examined the common area(s) of structurally intact but dysfunctional cortical tissue by using spatial normalization of PWI maps as well as symmetric voxel-wise inter-hemispheric comparisons. These new techniques allow comparison of the structurally intact but abnormally perfused areas of different individuals in the same stereotaxic space, and at the same time avoid problems due to regional perfusion differences and to possible observer-dependent biases. We found that strokes centring on the right basal ganglia which provoke spatial neglect induce abnormal perfusion in a circumscribed area of intact cortex that typically involves those three regions that have previously been described to provoke spatial neglect when damaged directly by cortical infarction: the superior temporal gyrus, the inferior parietal lobule and the inferior frontal gyrus. The data suggest that spatial neglect following a right basal ganglia lesion typically is caused by the dysfunction of (part of) these specific cortical areas.

Attention↗

PubMed2006

Apathy and the basal ganglia.

We should like to emphasize the following points: 1. Apathy is defined here as a quantified and observable behavioral syndrome consisting in a quantitative reduction of voluntary (or goal-directed) behaviors; 2. Therefore, apathy occurs when the systems that generate and control voluntary actions are altered; 3. These systems are mostly represented by the different subregions embedded in the Prefrontal cortex (PFC) and in the basal ganglia regions that are closely connected with the PFC; 4. In consequence, clinically, apathy is a prefrontal syndrome either due to direct lesions of the PFC or to lesions of basal ganglia areas that are closely related to the PFC; 5. Apathy is not a single entity but rather heterogeneous. Several different mechanisms may lead to apathy; Because there are several anatomical-functional prefrontal-basal ganglia circuits, the underlying mechanisms responsible for apathy may differ according to which prefrontal-basal ganglia circuit is affected; 6. In this context, apathy is the macroscopic results of the disruption of one or several elementary steps necessary for goal-directed behavior that are subserved by different prefrontal-basal ganglia circuits; 7. Intense apathy is related to caudate nucleus and GPi, disrupting associative and limbic pathways from/to the PFC; 8. in progressive supranuclear palsy (PSP) and focal lesions (caudate nuclei, GPi), apathy may be due to a loss of PFC activation; 9. In Parkinson's disease (PD), apathy may be due to a loss of signal focalization; 10. More globally, we propose that apathy may be explained by the impact of lesions or dysfunctions of the BG, because these lesions or dysfunctions lead to a loss of amplification of the relevant signal and/or to a loss of temporal and spatial focalization, both of which result in a diminished extraction of the relevant signal within the frontal cortex, thereby inhibiting the capacity of the frontal cortex to select, initiate, maintain and shift programs of action.

Basal Ganglia↗

PubMed2003

Neuroanatomical relationship between type 1 cannabinoid receptors and dopaminergic systems in the rat basal ganglia.

Dopamine and endocannabinoids are neurotransmitters known to play a role in the activity of the basal ganglia motor circuit. While a number of studies have demonstrated functional interactions between type 1 cannabinoid (CB1) receptors and dopaminergic systems, we still lack detailed neuroanatomical evidence to explain their relationship. Single- and double-labeling methods (in situ hybridization and immunohistochemistry) were employed to determine both the expression and localization of CB1 receptors and tyrosine hydroxylase (TH) in the basal ganglia. In the striatum, we found an intense signal for CB1 receptor transcripts but low signal for CB1 receptor protein, whereas in the globus pallidus and substantia nigra we found the opposite; no hybridization signal but intense immunoreactivity. Consequently, CB1 receptors are synthesized in the striatum and mostly transported to its target areas. No co-expression or co-localization of CB1 receptors and TH was found. In the caudate-putamen, globus pallidus and substantia nigra, TH-immunoreactive fibers were interwoven with the CB1 receptor-immunoreactive neuropil and fibers. Our data suggest that the majority of the striatal CB1 receptors are located presynaptically on inhibitory GABAergic terminals, in a position to modulate neurotransmitter release and influence the activity of substantia nigra dopaminergic neurons. In turn, afferent dopaminergic fibers from the substantia nigra innervate CB1 receptor-expressing striatal neurons that are known to also express dopamine receptors. In conclusion, these data provide a neuroanatomical basis to explain functional interactions between endocannabinoid and dopaminergic systems in the basal ganglia.

Animals↗

PubMed2005

Efferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes.

The olfactostriatum is a portion of the basal ganglia of snakes that receives substantial vomeronasal afferents through projections from the nucleus sphericus. In a preceding article, the olfactostriatum of garter snakes (Thamnophis sirtalis) was characterized on the basis of chemoarchitecture (distribution of serotonin, neuropeptide Y and tyrosine hydroxylase) and pattern of afferent connections [Martinez-Marcos, A., Ubeda-Banon, I., Lanuza, E., Halpern, M., 2005. Chemoarchitecture and afferent connections of the "olfactostriatum": a specialized vomeronasal structure within the basal ganglia of snakes. J. Chem. Neuroanat. 29, 49-69]. In the present study, its efferent connections have been investigated. The olfactostriatum projects to the main and accessory olfactory bulbs, lateral cortex, septal complex, ventral pallidum, external, ventral anterior and dorsolateral amygdalae, bed nucleus of the stria terminalis, preoptic area, lateral posterior hypothalamic nucleus, ventral tegmental area, substantia nigra and raphe nuclei. Tracer injections in the nucleus accumbens proper, a structure closely associated with the olfactostriatum, result in a similar pattern of efferent connections with the exception of those reaching the main and accessory olfactory bulbs, lateral cortex, external, ventral anterior and dorsolateral amygdalae and bed nucleus of the stria terminalis. These data, therefore, help to characterize the olfactostriatum, an apparently specialized area of the nucleus accumbens. Double labeling experiments after tracer injections in the nucleus sphericus and the lateral posterior hypothalamic nucleus demonstrate a pathway between these two structures through the olfactostriatum. Injections in the olfactostriatum and in the medial amygdala show parallel projections to the lateral posterior hypothalamic nucleus. Since this hypothalamic nucleus has been previously described as projecting to the hypoglossal nucleus, both, the medial amygdala and the olfactostriatum may mediate vomeronasal influence on tongue-flick behavior.

Amygdala↗

PubMed1999

Incidence and clinical significance of echogenic vasculature in the basal ganglia of newborns.

Cranial sonography has become the main modality of the investigation and diagnosis of a wide variety of neonatal intracranial abnormalities. Occasionally, cranial sonograms reveal basal ganglia and thalami bright echoes. It is believed that these lesions are indicative of vasculitis due to intrauterine infections, in particular with cytomegalovirus (CMV). We hypothesized that the incidence of proven neonatal intrauterine TORCH infection is low and that screening of all asymptomatic infants with bright lenticulostriate echodensities would not be cost-effective. We reviewed brain sonograms of 3700 infants, performed over a period of 3 1/2 years. Echogenic basal ganglia vasculature were observed in 75 patients (2%). Chart review performed for clinical presentation and TORCH studies showed that only one infant had confirmed intrauterine congenital infection, which was by CMV. This infant had no signs or symptoms of CMV. In addition, there were 4 patients with chromosomal anomalies among the 75 patients (5%), of these one had trisomy 13 and another-trisomy 21. Our results indicate that echogenic basal ganglia blood vessels are not an exceptional finding on cranial sonograms, and are seldom associated with intrauterine infection. We conclude that it is not cost-effective to screen infants with echogenic basal ganglia blood vessels for intrauterine infection, unless clinical suspicion exists.

Basal Ganglia↗

PubMed1999

Multisecond oscillations in firing rate in the basal ganglia: robust modulation by dopamine receptor activation and anesthesia.

Multisecond oscillations in firing rate in the basal ganglia: robust modulation by dopamine receptor activation and anesthesia. Studies of CNS electrophysiology have suggested an important role for oscillatory neuronal activity in sensory perception, sensorimotor integration, and movement timing. In extracellular single-unit recording studies in awake, immobilized rats, we have found that many tonically active neurons in the entopeduncular nucleus (n = 15), globus pallidus (n = 31), and substantia nigra pars reticulata (n = 31) have slow oscillations in firing rate in the seconds-to-minutes range. Basal oscillation amplitude ranged up to +/-50% of the mean firing rate. Spectral analysis was performed on spike trains to determine whether these multisecond oscillations were significantly periodic. Significant activity in power spectra (in the 2- to 60-s range of periods) from basal spike trains was found for 56% of neurons in these three nuclei. Spectral peaks corresponded to oscillations with mean periods of approximately 30 s in each nucleus. Multisecond baseline oscillations were also found in 21% of substantia nigra dopaminergic neurons. The dopamine agonist apomorphine (0.32 mg/kg iv, n = 10-15) profoundly affected multisecond oscillations, increasing oscillatory frequency (means of spectral peak periods were reduced to approximately 15 s) and increasing the regularity of the oscillations. Apomorphine effects on oscillations in firing rate were more consistent from unit to unit than were its effects on mean firing rates in the entopeduncular nucleus and substantia nigra. Apomorphine modulation of multisecond periodic oscillations was reversed by either D1 or D2 antagonists and was mimicked by the combination of selective D1 (SKF 81297) and D2 (quinpirole) agonists. Seventeen percent of neurons had additional baseline periodic activity in a faster range (0.4-2.0 s) related to ventilation. Multisecond periodicities were rarely found in neurons in anesthetized rats (n = 29), suggesting that this phenomenon is sensitive to overall reductions in central activity. The data demonstrate significant structure in basal ganglia neuron spiking activity at unexpectedly long time scales, as well as a novel effect of dopamine on firing pattern in this slow temporal domain. The modulation of multisecond periodicities in firing rate by dopaminergic agonists suggests the involvement of these patterns in behaviors and cognitive processes that are affected by dopamine. Periodic firing rate oscillations in basal ganglia output nuclei should strongly affect the firing patterns of target neurons and are likely involved in coordinating neural activity responsible for motor sequences. Modulation of slow, periodic oscillations in firing rate may be an important mechanism by which dopamine influences motor and cognitive processes in normal and dysfunctional states.

Anesthesia, General↗

PubMed2002

Metabolite alterations in basal ganglia associated with methamphetamine-related psychiatric symptoms. A proton MRS study.

Following the chronic use of methamphetamine, some individuals experience psychosis and anxiety. One reason may be the persistence of metabolite abnormalities in the brain of currently abstinent former methamphetamine users. In this study, N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr+PCr), and choline-containing compound (Cho) levels were measured in the left and right basal ganglia using proton magnetic resonance spectroscopy (MRS) in 13 abstinent methamphetamine users and 11 healthy comparison subjects with no history of illicit drug use. The methamphetamine users showed a significantly reduced Cr+PCr/Cho ratio in the bilateral basal ganglia compared with the healthy comparison subjects. Furthermore, the reduction in the Cr+PCr/Cho ratio was significantly correlated with the duration of methamphetamine use and with the severity of residual psychiatric symptoms. NAA/Cho ratios in the bilateral basal ganglia did not significantly differ between methamphetamine users and comparison subjects. These findings suggest that protracted use of methamphetamine may cause metabolite alterations in the basal ganglia. Furthermore, residual psychiatric symptoms may be attributable to the metabolite alterations in the basal ganglia.

Adult↗

PubMed2000

Intraoperative direct subcortical stimulation for identification of the internal capsule, combined with an image-guided stereotactic system during surgery for basal ganglia lesions.

BACKGROUND: The two main problems of surgery for basal ganglia lesions are: first, the difficulty of accurately localizing the lesion in this deep location; and second, the proximity to the internal capsule, with the risk of permanent postoperative sequelae. The author describes the use of intraoperative direct electrical subcortical stimulation in the identification and preservation of the internal capsule, combined with an image-guided stereotactic system for the selection of the best surgical approach in a case of deep cavernoma. CASE DESCRIPTION: A 33-year-old man was admitted to our institution with a history of three episodes of transitory left hemiparesia in the last 12 years. Neurological examination revealed a mild left weakness. Magnetic resonance imaging (MRI) showed typical features of a right posterior capsular-lentiform cavernoma. To prevent another hemorrhagic event, surgery was performed via a right transdistal sylvian approach, using a computer-assisted stereotactic method that allowed us to reach the lesion directly and direct stimulations to detect the subcortical pyramidal pathways. The patient had a transitory worsening with complete recovery in 10 days. Control MRI showed total resection. CONCLUSION: As described at the cortical level, the intraoperative direct subcortical stimulations seem also to represent an easy, safe, accurate, and reliable method of real-time functional identification of the internal capsule during surgery for basal ganglia lesions. The combination with an image-guided stereotactic system to accurately localize the lesion minimizes the risk of postoperative sequelae, and seems to warrant an increase of the surgical indications in this location.

Adult↗

PubMed1984

Basal ganglia role in behavior: importance of sensory gating and its relevance to psychiatry.

The neurophysiological basis of behavior and psychiatric disorders is for the most part unknown. However, over the years dysfunction of the dopaminergic system and, specifically, the basal ganglia have been implicated in many complex behaviors and psychiatric disorders. Evidence is presented in support of a basal ganglia role in sensory gating in the CNS and suggests a possible mechanism by which basal ganglia dysfunction may result in complex behavioral disturbances. Using schizophrenia as an example, this paper suggests that such disorders may to a certain extent represent a complex dysfunction of sensory filtering mechanisms in the brain. The suggestion is that the basal ganglia, acting as an active sensory information gating station, maintain the normal flow of afferent information to both ascending and descending structures. When this gating system is dysfunctional, unmodulated afferent information leads to inappropriate behavioral responses.

Animals↗

PubMed1985

[Traumatic hemorrhage in the basal ganglia in the child. Five cases].

Traumatic hemorrhages in the basal ganglia were seen in five children. The CT findings and the characteristics of these injuries were discussed. All of children were injured in car accidents. They ranged in age from 3 to 13 years. The patients comprised 3 boys and 2 girls. On admission, case 1 was conscious and case 2 was in a stupor. Case 1 and 2 were mild cases in which spotty hematomas were seen in the ganglionic region. They recovered fully. Case 3-5 were severe cases in which massive hematomas were seen in the ganglionic region. On admission, their consciousness ranged from stupor to coma. We performed operations on two of them but their recoveries were unsatisfactory. Their results were as follows. One had residual hemiparesis and dysarthria, one experienced tetraparesis and dysarthria and the last went from coma to a vegetative state. Concerning the directions of the impacts, 4 were hit in the frontal region or face and the last one received blows on the occipital region. Skull fractures were seen in two cases. Mandibula and clavicula fractures were seen in the other two cases. Only one child had no fractures. We conclude that pediatric traumatic hemorrhages in the basal ganglia are induced by severe impact on the frontal or occipital regions. The size of hematomas in this injury is spotty or massive. The massive type has a poor prognosis. On the other hand, the spotty type's prognosis is good. We speculate that impact to the head causes a shear strain in the ganglionic region. At that time, vessels in the area are injured.

Adolescent↗

PubMed1994

Germinomas of the basal ganglia and thalamus: MR findings and a comparison between MR and CT.

OBJECTIVE: The purpose of this study was to describe the MR imaging appearance of germinomas in the basal ganglia and thalamus and to compare the MR findings with CT findings. MATERIALS AND METHODS: Eleven MR studies of 10 patients with pathologically proved germinomas in the basal ganglia or thalamus were retrospectively reviewed. In nine of the 10, the MR findings were compared with CT findings. All patients were male, and all except one were in their second decade of life. All the tumors were located in paraventricular areas. RESULTS: Most of the tumors were 4-7 cm in diameter. MR images showed that the tumors were mostly cystic in five patients, mostly solid with cystic components in four, and solid without cystic components in one. The solid portion mostly was isointense relative to the cerebral cortex for all MR pulse sequences. The cystic portion was hyperintense relative to CSF on T1- and T2-weighted images. MR images showed intratumoral hemorrhage in seven patients. It appeared as an area of hyperintensity on T1- and T2-weighted images in five patients and as a fluid-fluid level with marked hypointensity on T2-weighted images in two. Hemorrhage was not visualized on CT scans in any patient. Flecked or amorphous calcifications visualized on CT scans in two patients were hardly detectable on MR images. Peritumoral edema was usually minimal. CT scans and MR images obtained after injection of contrast material both showed heterogeneous and dense enhancement in the solid portions of the tumors. CONCLUSION: MR images of germinoma in the basal ganglia and thalamus show a large paraventricular mass. Cystic areas, focal hemorrhages, and minimal surrounding edema are common. Unlike CT, MR imaging allows characterization of intratumoral hemorrhage.

Adolescent↗

PubMed1998

Basal ganglia organization in amphibians: evidence for a common pattern in tetrapods.

The results of recent studies investigating the connections and chemoarchitecture of the basal forebrain of amphibians provide strong evidence that tetrapod vertebrates share a common pattern of basal ganglia organization. This pattern includes the existence of dorsal and ventral striatopallidal systems, reciprocal connections between the striatopallidal complex and the diencephalic and mesencephalic basal plate (striato-nigral and nigro-striatal projections), and descending pathways from the striatopallidal system to the midbrain tectum and reticular formation. The connectional similarities are parallelled by similarities in the distribution of chemical markers of striatal and pallidal structures such as dopamine, substance P and enkephalin. Moreover, studies of development and expression of homeobox genes have given further support to the notion that both amniotic and anamniotic tetrapods have a common pattern of basal ganglia organization. A new nomenclature of basal forebrain structures in amphibians is proposed which reflects our current understanding of basal ganglia organization in this class of vertebrates.

Amphibians↗

PubMed2000

Near-real-time guidance using intraoperative magnetic resonance imaging for radical evacuation of hypertensive hematomas in the basal ganglia.

OBJECTIVE: To report our preliminary clinical experience in treating patients with hypertensive hemorrhage in the basal ganglia using a minimally invasive approach facilitated by intraoperative real-time imaging of an open magnetic resonance imaging (MRI) system and a newly designed cutting suction device. METHODS: We developed an artifact-free device for use during intraoperative MRI consisting of a guiding base that locks into a burr hole, a side-cutting composite-based cannula connected to a standard aspirator, and a handpiece that allows aspiration strength to be regulated by the surgeon. Thirteen patients with hypertensive bleeding in the basal ganglia were included in the study. Outcome was evaluated by mortality, Glasgow Outcome Scale score, activities of daily living score, and Rankin score at 2 weeks and at a median of 4.2 months after the hemorrhage. RESULTS: In this group of 13 patients, complete evacuation was achieved in 8 patients (62%) and subtotal evacuation of 75 to 90% of the initial volume in 4 patients (31%); the evacuation was partial in 1 patient (8%). Vascular malformations were preoperatively excluded angiographically. There was no rebleeding during surgery or postoperatively, as demonstrated by immediate postoperative MRI and computed tomography on the 1st postoperative day. Hematomas were evacuated on median Day 4 after the hemorrhage, varying between Day 1 and Day 8; evacuation was performed on Day 21 after the hemorrhage in one patient. Twelve of the 13 patients survived during a median follow-up time of 4.2 months. Neurological function improved in 11 of the 12 patients eligible for assessment. One patient with an additional head injury died 15 days after surgery from pulmonary embolism. CONCLUSION: This study shows an excellent outcome with regard to mortality and a positive trend regarding neurological outcome for the specific group of patients with hypertensive hematomas in the basal ganglia. This minimally invasive approach is feasible in the open intraoperative MRI in combination with the cutting suction device developed in our institution. Online imaging is extremely helpful for planning, guiding, and real-time monitoring of the procedure.

Adult↗

PubMed1983

The basal ganglia in extrapyramidal dysfunction.

The rapid advances in knowledge of basal ganglia circuitry and function in recent years have allowed the construction of a functional scheme to explain many facets of known pathologic states. The dichotomy of Parkinson's disease; akinesia with increased tone, and the mirror effects in Huntington's disease; hemiballismus and tardive dyskinesia, hyperkinesia with decreased tone are explained as due to two outputs of the system with an intervening inhibitory neuron which reverses the sign. The two outputs control different motor functions; pallidothalamic involved primarily with movements and nigrobrainstem involved primarily with muscle tone.

Basal Ganglia↗

PubMed1999

Catecholaminergic neurons in the diencephalon and basal ganglia of SIDS.

The catecholaminergic systems of sudden infant death syndrome victims were examined in the diencephalon and basal ganglia, in addition to the midbrain, pons, and medulla oblongata, using the immuno-histochemical method involving tyrosine hydroxylase. A significant decrease in tyrosine hydroxylase immunoreactivity was demonstrated in the basal ganglia of sudden infant death syndrome victims between 2 to 12 months of age compared with age-matched control subjects. This change in the basal ganglia may be a secondary finding induced by chronic hypoxia or repeated ischemia in sudden infant death syndrome but suggests impairment of the development of the neuronal connection from the brainstem to the upper cardiorespiratory control in sudden infant death syndrome.

Basal Ganglia↗

PubMed2002

Thalamic relay nuclei of the basal ganglia form both reciprocal and nonreciprocal cortical connections, linking multiple frontal cortical areas.

Thalamic relay nuclei transmit basal ganglia output to the frontal cortex, forming the last link in corticobasal ganglia circuitry. The thalamus regulates cortical activity through differential laminar connections, providing not only feedback, but also initiating "feedforward" loops, via nonreciprocal projections, that influence higher cortical areas. This study examines the organization of thalamic connections with cortex from basal ganglia relay nuclei, including ventral anterior (VA), ventral lateral (VL), and mediodorsal (MD) nuclei, in the Macaque monkey. Anterograde and bidirectional tracer injections ([3H]-amino acids, dextran conjugates of Fluorescein, Lucifer Yellow or FluoroRuby, or wheat germ agglutinin) into discrete VA/VL, MD, and frontal cortical sites demonstrate specific thalamocortical connections. VL projections target caudal motor areas (primary, supplementary, and caudal premotor areas), whereas VA projections target more rostral premotor areas (including cingulate and presupplementary motor areas) and MD projects to dorsolateral and orbital prefrontal cortices. Thalamocortical projections innervate cortical layers I and III, and to a lesser extent, layer V. In motor areas layer I projections are more extensive than those to layer III (and V). The complex laminar organization of projections from specific thalamic sites suggests differential regulation of cortical function. Injections of bidirectional tracers into thalamic and frontal cortical sites also show that in comparison to thalamocortical projections, corticothalamic projections to VA-VL and MD are more widespread. These findings demonstrate both reciprocal and nonreciprocal components to the thalamo-cortico-thalamic relay. Together, these experiments indicate a dual role for VA-VL and MD nuclei: (1) to relay basal ganglia output within specific cortical circuits and (2) to mediate information flow between cortical circuits.

Amino Acids↗

PubMed2006

Synchronizing activity of basal ganglia and pathophysiology of Parkinson's disease.

Early physiological studies emphasized changes in the discharge rate of basal ganglia in the pathophysiology of Parkinson's disease (PD), whereas recent studies stressed the role of the abnormal oscillatory activity and neuronal synchronization of pallidal cells. However, human observations cast doubt on the synchronization hypothesis since increased synchronization may be an epi-phenomenon of the tremor or of independent oscillators with similar frequency. Here, we show that modern actor/ critic models of the basal ganglia predict the emergence of synchronized activity in PD and that significant non-oscillatory and oscillatory correlations are found in MPTP primates. We conclude that the normal fluctuation of basal ganglia dopamine levels combined with local cortico-striatal learning rules lead to noncorrelated activity in the pallidum. Dopamine depletion, as in PD, results in correlated pallidal activity, and reduced information capacity. We therefore suggest that future deep brain stimulation (DBS) algorithms may be improved by desynchronizing pallidal activity.

Animals↗

PubMed2006

Parkinson's disease and other basal ganglia or movement disorders in a large nationwide cohort of Swedish welders.

INTRODUCTION: Although it has been hypothesised that metal welding and flame cutting are associated with an increased risk for Parkinson's disease due to manganese released in the welding fume, few rigorous cohort studies have evaluated this risk. METHODS: The authors examined the relation between employment as a welder and all basal ganglia and movement disorders (ICD-10, G20-26) in Sweden using nationwide and population based registers. All men recorded as welders or flame cutters (n = 49,488) in the 1960 or 1970 Swedish National Census were identified and their rates of specific basal ganglia and movement disorders between 1964 and 2003 were compared with those in an age and geographical area matched general population comparison cohort of gainfully employed men (n = 489,572). RESULTS: The overall rate for basal ganglia and movement disorders combined was similar for the welders and flame cutters compared with the general population (adjusted rate ratio (aRR) = 0.91 (95% CI 0.81 to 1.01). Similarly, the rate ratio for PD was 0.89 (95% CI 0.79 to 0.99). Adjusted rate ratios for other individual basal ganglia and movement disorders were also not significantly increased or decreased. Further analyses of Parkinson's disease by attained age, time period of follow up, geographical area of residency, and educational level revealed no significant differences between the welders and the general population. Rates for Parkinson's disease among welders in shipyards, where exposures to welding fumes are higher, were also similar to the general population (aRR = 0.95; 95% CI 0.70 to 1.28). CONCLUSION: This nationwide record linkage study offers no support for a relation between welding and Parkinson's disease or any other specific basal ganglia and movement disorders.

Adult↗