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Performance validity tests (PVTs) are not widely used beyond medico-legal contexts in the UK. A UK survey suggests clinicians have reservations about their accuracy in clinical settings. This study sought to explore the validity of PVTs in an acute adult neuropsychology setting and to establish a potential "false positive" (FP) base rate. Failures on the Medical Symptom Validity Test (MSVT) in a consecutive clinical series of 405 patients were evaluated systematically and allocated to groups depending on clinical context. All failures were checked against the test's "dementia profile". Of the 405 participants, 329 passed the MSVT (81.2%), while 76 participants (18.8%) failed based on standard criteria. A 5.2% rate of potentially 'unexplained' failures was found. Other reasons for failure were classified as: presumed malingered neurocognitive dysfunction (4.6%), dementia/significant cognitive impairment (3.7%), technical/visual problems (1.8%), and "unexplained failure" with contributory factors (2.4%). These results suggest test specificity between 0.95 and 0.90. Most of the clinically significantly impaired patients matched the dementia profile (86.7%). Our results support the sensitivity, but not the specificity, of the dementia profile. However, approximately 1 in 20 patients failed the MSVT despite an otherwise unremarkable neuropsychological presentation; moreover, mood and pain may affect MSVT performance. Clinical implications for interpreting test scores are discussed.
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Pruebas Neuropsicológicas , Adolescente , Adulto , Afecto , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Disfunción Cognitiva/diagnóstico , Demencia/diagnóstico , Reacciones Falso Positivas , Femenino , Humanos , Masculino , Simulación de Enfermedad/diagnóstico , Persona de Mediana Edad , Examen Neurológico , Dolor/psicología , Valor Predictivo de las Pruebas , Proyectos de Investigación , Autoinforme , Sensibilidad y Especificidad , Reino UnidoRESUMEN
UNLABELLED: Deep brain stimulation (DBS) of the periventricular/periaqueductal gray area and sensory thalamus can reduce pain intensity in patients with neuropathic pain. However, little is known about its impact on quality of life, emotional well-being, and cognition. This study followed up 18 patients who had received DBS for neuropathic pain. Each participant had previously undergone psychometric evaluation of each of the above areas as part of a routine presurgical neuropsychological assessment. Commensurate measures were employed at a follow-up assessment at least 6 months postsurgery. DBS significantly improved mood, anxiety, and aspects of quality of life. Improvements correlated with reduced pain severity. However, the sample continued to show impairments in most areas when compared against normative data published on nonclinical samples. There was little change in general cognitive functioning, aside from deterioration in spatial working memory. However, improvements in pain severity were associated with less improvement (and even deterioration) on measures of executive cognitive functioning. Improvements in emotional well-being also were correlated with changes in cognition. These results suggest that DBS of the periventricular/periaqueductal gray and/or sensory thalamus improves quality of life and emotional well-being in sufferers, although there is some indication of executive dysfunction, particularly among those reporting greatest pain alleviation. PERSPECTIVE: This article examines the neuropsychological outcomes of DBS surgery as a treatment for neuropathic pain. This intervention was found to improve pain severity, emotional well-being, and quality of life, although such benefits may be accompanied by reduced ability on tasks measuring executive functioning.
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Estimulación Encefálica Profunda , Neuralgia/terapia , Adulto , Afecto/fisiología , Ansiedad/etiología , Ansiedad/fisiopatología , Ansiedad/terapia , Cognición/fisiología , Estimulación Encefálica Profunda/efectos adversos , Emociones/fisiología , Función Ejecutiva/fisiología , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/fisiopatología , Memoria a Corto Plazo/fisiología , Persona de Mediana Edad , Neuralgia/complicaciones , Neuralgia/fisiopatología , Neuralgia/psicología , Sustancia Gris Periacueductal/fisiopatología , Sustancia Gris Periacueductal/cirugía , Calidad de Vida , Índice de Severidad de la Enfermedad , Percepción Espacial/fisiología , Resultado del TratamientoRESUMEN
AIM: The distribution and quality of brain recovery following pediatric arterial ischemic stroke remains controversial. The literature suggests that age at stroke may be an important modulator of neuropsychological outcome, with reports inferring either greater vulnerability or plasticity in the nascent brain. Our aim was to investigate neuropsychological outcomes following pediatric stroke in a clinical sample with reference to age at lesion, lesion laterality, elapsed time from stroke to assessment, and persistent neurological sequelae. METHODS: Using comprehensive neuropsychological assessment batteries, we investigated retrospectively a large (n = 44) and evenly distributed group of children who had ischemic stroke during "infancy" (1 month to 1 year), "early childhood" (1 to 6 years), and "late childhood" (6 to 16 years). RESULTS: Children who suffered a stroke performed significantly worse on a range of neuropsychological measures when compared to a normative sample. However, children who suffered a stroke between 1 and 6 years old demonstrated better preserved neuropsychological profiles than either the earlier (before age 1) or later (after age 6) age groups. In addition, those children suffering a left hemisphere lesion performed more poorly on a range of neuropsychological measures than did children with right hemisphere lesions. INTERPRETATION: Age at stroke is an important determinant of recovery following insult and may modulate neuropsychological and cognitive outcome.
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Encéfalo/fisiopatología , Trastornos del Conocimiento/etiología , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/fisiopatología , Adolescente , Factores de Edad , Edad de Inicio , Niño , Preescolar , Trastornos del Conocimiento/fisiopatología , Femenino , Humanos , Lactante , Masculino , Plasticidad Neuronal , Pruebas Neuropsicológicas/estadística & datos numéricos , Dinámicas no Lineales , Solución de Problemas , Estudios RetrospectivosRESUMEN
BACKGROUND AND PURPOSE: The International Subarachnoid Aneurysm Trial (ISAT) reported lower rates of death and disability with endovascular versus neurosurgical treatment of ruptured intracranial aneurysms. However, assessment of functional outcome was limited to the modified Rankin Scale, which is known to be insensitive to cognitive function. A neuropsychological substudy (N-ISAT) was therefore done in all recruits from 8 ISAT centers in the United Kingdom. METHODS: Detailed neuropsychological assessment was performed at a 12-month follow-up visit. Impairment was defined as performance below the 5th percentile of the study population on at least 2 tests in >or=2 major cognitive domains. Analysis was restricted to patients who were not known to be otherwise disabled according to the modified Rankin Scale (ie, modified Rankin Scale 0 to 2). RESULTS: Of 836 patients randomized in ISAT in the 8 UK centers (411 allocated endovascular treatment versus 425 neurosurgery), 224 were dead or disabled before 12-month follow-up (78 allocated endovascular treatment versus 135 neurosurgery). Of the remaining 612 patients eligible for neuropsychological assessment, 137 (65 allocated endovascular treatment versus 72 neurosurgery) did not attend. Of the 474 nondisabled patients who were assessed, 152 (32.1%) had cognitive impairment. Patients with cognitive impairment had reduced self-reported health-related quality of life (P<0.001) in both treatment groups, but cognitive impairment was less common in those allocated endovascular treatment (70 of 262 versus 82 of 212 allocated neurosurgery, OR=0.58, 95% CI 0.38 to 0.87, P=0.0055). The incidence of epilepsy was also lower in the N-ISAT endovascular group (7 versus 18, OR=0.30, 0.11 to 0.77, P=0.005) but was independent of the effect on cognitive function. CONCLUSIONS: Cognitive impairment occurred in approximately one third of patients who were not otherwise disabled according to the modified Rankin Scale in N-ISAT and was more frequent in the neurosurgery group. These results have implications for management of ruptured intracranial aneurysms and more generally for interpretation of the outcomes of clinical trials that use the modified Rankin Scale.
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Aneurisma Roto/terapia , Cognición/fisiología , Embolización Terapéutica , Aneurisma Intracraneal/terapia , Adulto , Anciano , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Oportunidad Relativa , Resultado del Tratamiento , Reino UnidoRESUMEN
Cognitive functioning and health-related quality of life were assessed pre- and post-operatively in a consecutive series of 31 Parkinson's disease patients who underwent stereotactic unilateral thalamotomy (22 left-sided, 9 right-sided) for tremor alleviation. Neuropsychological functions assessed included verbal and visual memory, language and speech production, verbal and non-verbal reasoning, and attention and working memory. Health-related quality of life measures included both general and disease-specific questionnaires. We found a statistically significant post-operative decline in phonetic verbal fluency scores for left-operated patients, as well as improvements in self-ratings of stigma and bodily discomfort on the disease-specific quality of life questionnaire. These findings suggest that thalamotomy, when indicated, has limited cognitive sequelae and may result in improved quality of life in areas specific to Parkinson's disease.
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Trastornos del Conocimiento/cirugía , Cognición/fisiología , Calidad de Vida , Tálamo/cirugía , Temblor/psicología , Temblor/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Trastornos del Conocimiento/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/cirugía , Estudios Retrospectivos , Temblor/etiología , Adulto JovenRESUMEN
BACKGROUND: The neuropsychological arm of the International Subarachnoid Aneurysm Trial (N-ISAT) evaluated the cognitive outcome of 573 patients at 12 months following subarachnoid haemorrhage (SAH). The assessment included 29 psychometric measures, yielding a substantial and complex body of data. We have explored alternative and optimal methodologies for analysing and summarising these data to enable the estimation of a cognitive complication rate (CCR). Any differences in cognitive outcome between the two arms of the trial are not however reported here. METHODS: All individual test scores were transformed into z-scores and a 5th percentile cut-off for impairment was established. A principal components analysis (PCA) was applied to these data to mathematically transform correlated test scores into a smaller number of uncorrelated principal components, or cognitive 'domains'. These domains formed the basis for grouping and weighting individual patients' impaired scores on individual measures. In order to increase the sample size, a series of methods for handling missing data were applied. RESULTS: We estimated a 34.1% CCR in all those patients seen face-to-face, rising to 37.4% CCR with the inclusion of patients who were unable to attend assessment for reason related to the index SAH. This group demonstrated significantly more self and carer/relative rated disability on a Health Related Quality of Life questionnaire, than patients classified as having no functionally significant cognitive deficits. CONCLUSION: Evaluating neuropsychological outcome in a large RCT involves unique methodological and organizational challenges. We have demonstrated how these problems may be addressed by re-classifying interval data from 29 measures into a dichotomous CCR. We have presented a 'sliding scale' of undifferentiated individual cognitive impairments, and then on the basis of PCA-derived cognitive 'domains', included consideration of the distribution of impairments in these terms. In order to maximize sample size we have suggested ways for patients who did not complete the entire protocol to be included in the overall CCR. ISAT TRIAL REGISTRATION: ISRCTN49866681.
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With thousands of complementary and alternative medicine (CAM) treatments currently being used in the United States today, it is challenging to design a concise body of CAM content which will fit into already overly full curricula for health care students. The purpose of this article is to outline key principles which 15 National Center for Complementary and Alternative Medicine-funded education programs found useful when developing CAM course-work and selecting CAM content. Three key guiding principles are discussed: teach foundational CAM competencies to give students a framework for learning about CAM; choose specific content on the basis of evidence, demographics and condition (what conditions are most appropriate for CAM therapies?); and finally, provide students with skills for future learning, including where to find reliable information about CAM and how to search the scientific literature and assess the results of CAM research. Most of the programs developed evidence-based guides to help students find reliable CAM resources. The cumulative experiences of the 15 programs have been compiled, and an annotated table outlining the most highly recommended resources about CAM is presented.
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Terapias Complementarias/educación , Curriculum , Educación de Postgrado en Medicina/normas , Educación de Pregrado en Medicina/normas , Educación en Enfermería/normas , Terapias Complementarias/normas , Atención a la Salud/normas , Medicina Basada en la Evidencia/educación , Humanos , Bibliotecas Médicas , Informática Médica , Estados UnidosRESUMEN
BACKGROUND: Early onset idiopathic generalised dystonia is a progressive and profoundly disabling condition. Medical treatment may ameliorate symptoms. However, many children have profound, intractable disability including the loss of ambulation and speech, and difficulties with feeding. Following the failure of medical management, deep brain stimulation (DBS) of the globus pallidus internus (GPi) has emerged as an alternative treatment for the disorder. METHODS: We describe four children who presented with dystonia. RESULTS: Following the failure of a range of medical therapies, DBS systems were implanted in the GPi in an attempt to ameliorate the children's disabilities. All children found dystonic movements to be less disabling following surgery. Compared with preoperative Burke, Fahn and Marsden Dystonia Rating Scale scores, postoperative scores at 6 months were improved. CONCLUSIONS: DBS is effective in improving symptoms and function in children with idiopathic dystonia refractory to medical treatment. Whilst surgery is complex and can be associated with intraoperative and postoperative complications, this intervention should be considered following the failure of medical therapy.
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Estimulación Encefálica Profunda/métodos , Trastornos Distónicos/terapia , Adolescente , Niño , Femenino , Estudios de Seguimiento , Globo Pálido/cirugía , Humanos , Masculino , Resultado del TratamientoRESUMEN
The common belief that primary dystonia is a purely motor disorder has recently been challenged. We examined separately the cognitive profiles of symptomatic (SYM) and nonsymptomatic (N-SYM) groups of carriers of DYT1 mutation using a comprehensive neuropsychological test battery. Self-report inventories of anxiety, depression, and pain levels were also administered, as well as manual motor dexterity assessment. Each group was matched with healthy controls by age, sex, mother tongue, and education. No significant differences between the SYM group to its control group were found on cognitive tests evaluating verbal and nonverbal abstract abilities, attention, information processing speed, and spatial organization. However, the SYM group showed increased verbal memory retroactive interference. Interestingly, the patients also showed higher semantic fluency performance. No significant differences between the N-SYM group to controls were found. It was concluded that symptomatic DYT1 mutation carriers do not suffer the distinctive cognitive decline that is seen in other primary degenerative extrapyramidal disorders.
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Distonía/genética , Distonía/fisiopatología , Chaperonas Moleculares/genética , Pruebas Neuropsicológicas , Adulto , Anciano , Estudios de Casos y Controles , Cognición/fisiología , Distonía/clasificación , Femenino , Humanos , Aprendizaje/fisiología , Masculino , Persona de Mediana Edad , Oportunidad RelativaRESUMEN
Objectives. This is a prospective study to determine the outcomes of subthalamic nucleus (STN) vs. globus pallidus internus (GPi) deep brain stimulation (DBS) at our institution. Materials and Methods. We studied a total of 39 patients - 29 with STN and 10 with GPi DBS over a period of up to 6 years. Mean ages in the two groups were similar (59 and 60 years, respectively) and disease duration prior to implantation was similar (9.6 and 11.7 years, respectively). Unified Parkinson Disease Rating Scale (UPDRS) was recorded preoperatively and at follow-up (at least at 6-month intervals). Medications also were recorded, and each patient's levodopa equivalent units (LEU) were calculated. Results were analyzed using a paired Student's t-test. Results. LEU reduced significantly (p < 0.05) in the STN group (5.7 to 3.7) but not the GPi group. Both targets significantly improved part 3 and part 4 scores of the UPDRS but GPi DBS did not improve part 2 scores (activities of daily living). STN DBS had much better outcome on the motor "off" scores of the UPDRS, whereas GPi only improved tremor. A comparison of the "earliest 10" and "most recent 10" STN patients showed a significant improvement in outcome in the most recent cases. Conclusions. In our group, STN was more effective for alleviating the symptoms of Parkinson disease, even in older patients with significant dyskinesias. Better patient selection and greater experience have led to more improvement in the more recent patients.
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As advances in medicine and surgery lead to reductions in mortality rates for life-threatening conditions, it has become increasingly important to refine the methodology of auditing long-term morbidity. The inclusion of appropriate neuropsychological outcomes in a large multicentre randomized clinical trial poses considerable methodological and logistical difficulties. This paper presents a model developed to implement such a multicentre neuropsychological and quality of life audit for a subset of patients within the International Subarachnoid Aneurysm Trial (ISAT), the largest ever randomized trial in the treatment of subarachnoid haemorrhage. Based on our experience of collecting quality of life and neuropsychological outcomes from more than 550 patients, data are presented on the relative cost and efficacy of different organizational strategies, methods of canvassing patients and associated response rates. On the basis of this experience, we estimate a potential recruitment pool of 135 cases would be required to obtain some neuropsychological data on 100 cases. The design of any similar trial would therefore need to accommodate a loss to follow-up of approximately one third of the sample. In addition, our experience suggests that for a trial of this size and complexity, the deployment of centrally-based co-ordinators travelling to satellite centres is more cost-effective than employing co-ordinators based at those centres. Extrapolations from the observations and calculations reported here can be employed as an evidence base to inform the design of neuropsychological outcome studies in large multicentre trials.
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Estudios Multicéntricos como Asunto , Neuropsicología , Evaluación de Resultado en la Atención de Salud/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto , Humanos , Modelos Psicológicos , Evaluación de Resultado en la Atención de Salud/economía , Selección de Paciente , Calidad de Vida , Hemorragia Subaracnoidea/psicología , Hemorragia Subaracnoidea/terapiaRESUMEN
We obtained (31)P magnetic resonance spectra from the brains in vivo of 101 males (range 6-72 years). In addition, cognitive test data were obtained from 42 boys (6-13 years) and from 26 adult males (22-56 years) of this test group. Significant correlations were observed in both adults and children between various inorganic phosphate (Pi)-containing (31)P peak ratios [e.g. Pi/adenosine triphosphate (ATP)] and (predominantly verbal) cognitive tasks. No change in the Pi/ATP ratio was observed across the age range studied. Brain pH was shown to decrease significantly with age in a relationship best described by a decaying exponential. This indicated that brain pH does not stabilize at adult values until at least the late teens. We explored the possibility of a relationship between brain pH and neuronal density. In particular, we noted that our previous observation of a relationship between pH and IQ in children was not readily detected in the adult populations, whereas phosphorus metabolite ratios (in particular, those containing Pi) were found to correlate with (predominantly verbal) cognitive task performance in both adults and children. We assessed how these observations may be interpreted in the context of a metabolic vs. histological debate.
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Envejecimiento , Química Encefálica/fisiología , Encéfalo/fisiología , Cognición/fisiología , Metabolismo Energético , Adolescente , Adulto , Anciano , Niño , Humanos , Concentración de Iones de Hidrógeno , Pruebas de Inteligencia , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Isótopos de Fósforo/análisis , Isótopos de Fósforo/metabolismoRESUMEN
One explanation for the weak relationship between neuropsychological deficits and conventional measures of disease burden in multiple sclerosis is that brain 'plasticity' allows adaptive reorganization of cognitive functions to limit impairment, despite injury. We have tested this hypothesis. Ten patients with multiple sclerosis and 11 healthy controls were studied using a functional MRI (fMRI) counting Stroop task. The two subject groups had comparable performances, but a predominantly left medial prefrontal region [Brodmann area (BA) 8/9/10] was more active during the task in patients than in controls (corrected P < 0.001), while a right frontal region (including BA 45 and the basal ganglia) was more active in controls than in patients (corrected P = 0.004). The magnitude of the differences correlated with the normalized brain parenchymal volume, a measure of disease burden (r = -0.72, P = 0.02). We then tested the effects of acute administration of rivastigmine, a central cholinesterase inhibitor, on patterns of brain activation. In five out of five multiple sclerosis patients there was a relative normalization of the abnormal Stroop-associated brain activation, although no change in the patterns of brain activation was found in any of four healthy controls given the drug and tested in the same way. We suggest that recruitment of medial prefrontal cortex is a form of adaptive brain plasticity that compensates, in part, for relative deficits in processing related to the reduced right prefrontal cortex activity with multiple sclerosis. This functional plasticity is modulated by cholinergic agonism and must arise from potentially highly dynamic mechanisms such as the 'unmasking' of latent pathways.
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Carbamatos/uso terapéutico , Inhibidores de la Colinesterasa/uso terapéutico , Cognición/efectos de los fármacos , Esclerosis Múltiple/fisiopatología , Plasticidad Neuronal/efectos de los fármacos , Fenilcarbamatos , Adulto , Método Doble Ciego , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/tratamiento farmacológico , Esclerosis Múltiple/psicología , Pruebas Neuropsicológicas , Corteza Prefrontal/fisiopatología , RivastigminaRESUMEN
Primary dystonia is a disorder of movement for which no consistent pathophysiology has been identified; in the absence of evidence to the contrary, it is assumed to be cognitively benign. We have studied a clinically heterogeneous group of 14 patients with primary dystonia on a battery of neuropsychological tests. Despite well-preserved speed of information processing, language, spatial, memory and general intellectual skills relative to normal controls, we have identified a constellation of attentional-executive cognitive deficits on the Cambridge Neuropsychological Test Automated Battery (CANTAB). Specifically, patients demonstrated significant difficulties negotiating the extra-dimensional set-shifting phase of the IED task. The implications of these findings for the pathophysiology of primary dystonia are discussed. This is, to the best of our knowledge, the first report of a significant cognitive deficit in patients with primary dystonia.
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Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/etiología , Distonía/complicaciones , Adulto , Encéfalo/patología , Trastornos del Conocimiento/fisiopatología , Evaluación de la Discapacidad , Distonía/patología , Distonía/fisiopatología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Trastornos de la Percepción/complicaciones , Trastornos de la Percepción/fisiopatología , Tiempo de Reacción , Índice de Severidad de la Enfermedad , Percepción Visual/fisiologíaRESUMEN
We successfully treated a patient with familial myoclonic dystonia (FMD), which primarily affected his neck muscles, with bilateral deep brain stimulation (DBS) to the medial pallidum, and investigated the role of the medial pallidum in FMD. A patient with FMD underwent bilateral implantation of DBS electrodes during which field potentials (FPs) in the medial pallidum and electromyograms (EMGs) from the affected neck muscles were recorded. The effects of high-frequency DBS to the medial pallidum on the FMD were also assessed by recording EMGs during and immediately after implantation, as well as 6 days and 8 weeks postoperatively. During spontaneous myoclonic episodes, increased FPs oscillating at 4 and 8 Hz were recorded from the medial pallidum; these correlated strongly with phasic EMG activity at the same frequencies in the contralateral affected muscles. The EMG activity was suppressed by stimulating the contralateral medial pallidum at 100 Hz during the operation and continuous bilateral DBS from an implanted stimulator abolished myoclonic activity even more effectively postoperatively. The phasic pallidal activity correlated with and led the myoclonic muscle activity, and the myoclonus was suppressed by bilateral pallidal DBS, suggesting that the medial pallidum was involved in the generation of the myoclonic activity. High-frequency DBS may suppress the myoclonus by desynchronising abnormal pallidal oscillations. This case study has significant clinical implications, because at present, there is no effective treatment for focal myoclonic dystonia.
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Trastornos Distónicos/fisiopatología , Electroencefalografía , Electromiografía , Globo Pálido/fisiopatología , Músculos del Cuello/inervación , Adulto , Dominancia Cerebral/fisiología , Trastornos Distónicos/diagnóstico , Trastornos Distónicos/genética , Trastornos Distónicos/terapia , Terapia por Estimulación Eléctrica , Electrodos Implantados , Humanos , MasculinoRESUMEN
It has been demonstrated that selective unilateral surgical ablation of posteroventral globus pallidus interna relieves the movement disorders associated with advanced Parkinson's disease, without necessarily incurring the executive cognitive sequelae that have been observed following gross pathological lesions to this brain region. This finding is consistent with established theory that underlying neuronal circuitry is functionally segregated into parallel cortico-striatal-pallidal-thalamo-cortical 'loops'. We have studied a series of 12 patients with advanced Parkinson's disease at baseline, and then following bilateral pallidotomy, with a battery of neuropsychological tests including the Cambridge Neuro psychological Test Automated Battery. We identified a selective and universal loss of individual patients' ability to shift attention to novel dimensions in a test of abstract rule-learning following surgery, which was not reliably associated with any other change in cognition, personality, mood or medication. This finding is rare in its specificity and has implications for theoretical models of the functional architecture and pathophysiology of the globus pallidus, and the clinical practice of pallidotomy.