Parkinson Disease: DeLong MR

Rye D, DeLong MR. · No affiliation provided · Arch Neurol. · Pubmed #12633141 links to  free full text

This publication has no abstract.

DeLong MR, Wichmann T. · No affiliation provided · Ann Neurol. · Pubmed #11220732 No free full text.

This publication has no abstract.

DeLong MR, Wichmann T. · Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA. · Arch Neurol. · Pubmed #17210805 links to  free full text

Abstract: Views of the anatomy and function of the basal ganglia and their role in motor and nonmotor disorders have undergone major revisions during the past decades. The basal ganglia are now appreciated as components of parallel, reentrant cortico-subcortical circuits, which originate from individual cortical areas, traverse the basal ganglia and thalamus, and terminate in their respective areas of origin in the frontal lobe. Further research and clinical experience have resulted in new insights and perspectives on the details of the circuitry and on the role of these structures in Parkinson disease and other basal ganglia disorders. On the basis of anatomical and physiological studies and the striking success of focused surgical interventions, it seems appropriate to view these varied clinical disorders as circuit disorders, resulting from pathologic disturbances in neuronal activity throughout specific cortico-subcortical loops.

Wichmann T, DeLong MR. · Department of Neurology, Emory University, Atlanta, GA 30322, USA. · J Neural Transm Suppl. · Pubmed #17017504 No free full text.

Abstract: In the traditional model of the pathophysiology of parkinsonism, parkinsonian motor signs are viewed as the result of changes in discharge rates in the basal ganglia. However, not all experimental findings can be explained by rate changes alone, and changes in discharge patterns in these nuclei are increasingly emphasized as pathophysiologically important, including changes in burst discharges, in synchrony, and in oscillatory activity. This brief review highlights the pathophysiologic relevance of these rate and pattern changes in the pathophysiology of parkinsonism.

McDonald WM, Richard IH, DeLong MR. · Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, USA. · Biol Psychiatry. · Pubmed #12893111 No free full text.

Abstract: Parkinson's disease (PD) is primarily a disease of elderly individuals with a peak age at onset of 55 to 66 years. It is characterized by bradykinesia, rigidity, tremor, and postural instability; and affects approximately 1 million individuals in the US and is the second most common neurodegenerative disease next to Alzheimer's disease. The motor symptoms of PD are the focus of pharmacotherapy, yet the nonmotor symptoms (e.g., dementia, psychosis, anxiety, insomnia, autonomic dysfunction, and mood disturbances) can be the most disturbing, disabling, and misunderstood aspects of the disease. Depressive symptoms occur in approximately half of PD patients and are a significant cause of functional impairment for PD patients. There is accumulating evidence suggesting that depression in PD is secondary to the underlying neuroanatomical degeneration, rather than simply a reaction to the psychosocial stress and disability. The incidence of depression is correlated with changes in central serotonergic function and neurodegeneration of specific cortical and subcortical pathways. Understanding comorbid depression in PD may therefore add to the understanding of the neuroanatomical basis of melancholia.

Wichmann T, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. · Ann N Y Acad Sci. · Pubmed #12846988 No free full text.

Abstract: The striatum is viewed as the principal input structure of the basal ganglia, while the internal pallidal segment (GPi) and the substantia nigra pars reticulata (SNr) are output structures. Input and output structures are linked via a monosynaptic "direct" pathway and a polysynaptic "indirect" pathway involving the external pallidal segment (GPe) and the subthalamic nucleus (STN). According to current schemes, striatal dopamine (DA) enhances transmission along the direct pathway (via D1 receptors), and reduces transmission over the indirect pathway (via D2 receptors). DA also acts on receptors in GPe, GPi, SNr, and STN. Electrophysiologic and other studies in primates rendered parkinsonian by treatment with the dopaminergic neurotoxin MPTP have demonstrated a reduction of neuronal activity of GPe and an increase of neuronal discharge in STN, GPi. and SNr. These findings are compatible with the view that striatal DA loss results in increased activity over the indirect pathway. Prominent bursting, oscillatory discharge patterns, and increased synchronization of neighboring neurons are found throughout the basal ganglia. These may result from changes in the activity of local circuits (e.g., the GPe-STN "pacemaker") or from more global abnormalities of the basal ganglia-thalamocortical network. These findings have been replicated in human patients undergoing microelectrode-guided stereotactic procedures targeted at GPi or STN. PET studies in patients with Parkinson's disease have lent further support to the proposed circuit abnormalities. The current models of basal ganglia function have recently been criticized. For instance, the strict separation of direct and indirect pathways and the segregation of D1 and D2 receptors have been questioned, and the almost complete absence of motor side effects of pallidal or thalamic lesions in human patients and animals is inconsistent. These results suggest that changes in discharge patterns and synchronization between basal ganglia neurons, abnormal network interactions, and compensatory mechanisms are at least as important in the pathophysiology of parkinsonism as changes in discharge rates in individual basal ganglia nuclei. Lesions of GPi or STN are effective in treating parkinsonism, because they reduce or abolish abnormal basal ganglia output, enabling remaining circuits to function more normally.

Wichmann T, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA. · Adv Neurol. · Pubmed #12442660 No free full text.

This publication has no abstract.

Okun MS, McDonald WM, DeLong MR. · Department of Neurology, Emory University, 1639 Pierce Dr, Suite 6000, Atlanta, GA 30322, USA. · Arch Neurol. · Pubmed #12020264 links to  free full text

Abstract: BACKGROUND: Many patients with Parkinson disease (PD) suffer from nonmotor symptoms including depression, anxiety, sexual dysfunction, decreased energy level, and an overall decline in quality of life. Comorbid depression, hypothyroidism, and sleep disorders may account for some, but not all, of these problems. Testosterone deficiency affects 20% to 25% of males over the age of 60 years in the general population and may cause signs and symptoms of the nonmotor symptoms seen in PD. We observed numerous patients with PD whose nonmotor symptoms were refractory to treatment. OBJECTIVE: To determine whether treatment of comorbid testosterone deficiency in male patients with PD can lead to improvements in refractory nonmotor symptoms. METHODS: Case studies were reviewed of the first 5 male patients who had PD with symptoms of testosterone deficiency who were treated in our clinic. All patients had low serum testosterone levels. Screening for testosterone deficiency symptoms using the St Louis Testosterone Deficiency Questionnaire was performed for 4 of the 5 patients. Additionally, to assess the prevalence of PD, total testosterone levels in 68 patients in our PD registry were sent for evaluation. RESULTS: Following testosterone replacement therapy, all 5 patients experienced significant improvements in their refractory nonmotor symptoms. Of 68 male patients with PD enrolled in our PD registry, 24 (35%) had plasma evidence of testosterone deficiency. We also noted that the risk of testosterone deficiency per decade was found to increase 2.8-fold per decade (P<.001), paralleling that which is found in the general elderly male population. CONCLUSIONS: The findings from this study reveal the heretofore unrecognized high prevalence of testosterone deficiency in elderly male patients with PD similar to that found in the general population. These symptoms, which may be refractory to antidepressants, anxiolytics, and antiparkinsonian medications, may respond to treatment with testosterone. More rigorous controlled studies will need to be undertaken to examine the treatment of this common comorbidity in male patients with PD.

Obeso JA, Rodriguez-Oroz MC, Rodriguez M, Macias R, Alvarez L, Guridi J, Vitek J, DeLong MR. · Department of Neurology and Neurosurgery, Clinica Universitaria and Medical School, University of Navarra, Pamplona, Spain. · Neurology. · Pubmed #11188978 No free full text.

Abstract: Dopamine depletion induces a series of changes in the basal ganglia motor circuit that underlie the origin of the cardinal features of Parkinson's disease. It has now been established that hyperactivity of the subthalamic nucleus (STN) is an essential feature of the parkinsonian state. This leads to increased excitatory driving onto the globus pallidum internum (GPi) and substantia nigra reticulata (SNr) which, in turn, overinhibits the motor projections to the thalamus and brainstem. The STN and GPi have become the preferred targets for surgery to treat PD. In keeping with the classic pathophysiologic model, physiologic and neuroimaging studies in patients have shown that lesioning or functional blockades (by deep brain stimulation, or DBS) of these nuclei increased cortical activation, in parallel with clinical improvements of bradykinesia. Neuronal recording during surgery has also shown tremor-related activity in both the STN and GPi. However, the pathophysiologic model of the basal ganglia needs further refinement to provide a more detailed explanation of the origin of both tremor and rigidity in Parkinson's disease and to explain the antidyskinetic effect of surgery of the GPi and STN.

Obeso JA, Rodriguez-Oroz MC, Rodriguez M, DeLong MR, Olanow CW. · Department of Neurology and Neurosurgery, Clínica Universitaria and Medical School, University of Navarra, Pamplona, Spain. · Ann Neurol. · Pubmed #10762129 No free full text.

Abstract: The anatomical and physiological basis of levodopa-induced dyskinesias (LIDs) in patients with Parkinson's disease (PD) is reviewed in the light of the current model for the organization of the basal ganglia. This model, which was developed in the late 1980s, works relatively well in explaining the motor features of PD but, for example, it does not account for why tremor, rigidity, bradykinesia, gait dysfunction and postural instability present to differing degrees in different patients, and may respond differently to levodopa treatment or surgical procedures. Recent information suggests that LIDs develop as a consequence of pulsatile stimulation of dopamine receptors, with consequent dysregulation of genes and proteins in downstream neurons resulting in changes in neuronal firing patterns. A modified model of the basal ganglia in PD patients with LID is proposed, which incorporates more recent clinical and experimental data.

Bronstein JM, DeSalles A, DeLong MR. · Department of Neurology, University of California, Los Angeles, School of Medicine, 90024, USA. · Arch Neurol. · Pubmed #10488806 links to  free full text

Abstract: The objective of this workshop was to provide recommendations on several issues involving pallidotomy for patients with medically intractable Parkinson disease to physicians, patients, and other health care providers. An international consortium of experts in neurology, neurosurgery, and neurophysiology who had extensive experience with pallidotomy were invited to the workshop. Participants were sent background materials from the scientific literature for review-based participant recommendations. A proposed agenda was circulated to all participants before the workshop, and the final agenda was based on their recommendations. Topics were introduced at the workshop by members of the organizing committee, followed by extensive group discussion. A draft of a consensus statement, based on the previous day's discussion, was circulated and further modifications were made. The final statement was agreed on by all members.The conclusions of the participants were: (1) Pallidotomy should be performed only at centers that have a team of physicians with substantial expertise and experience in the field. (2) Patients with disabling idiopathic Parkinson disease, without dementia, and who have exhausted medical therapy should be considered for pallidotomy. (3) All patients should be examined by means of standardized rating scales both preoperatively and postoperatively to ensure quality of care at each center. (4) Symptoms that respond best to pallidotomy include medication-induced dyskinesias, rigidity, and tremor, while balance, gait disorders, and hypophonia are generally less responsive to surgery. Benefits of pallidotomy appear to be long lasting. (5) Each institution's complication rate should be discussed before surgery.

Vitek JL, Hashimoto T, Peoples J, DeLong MR, Bakay RA. · Emory University School of Medicine, Atlanta, Georgia, USA. · Mov Disord. · Pubmed #15300655 No free full text.

Abstract: High frequency (>100Hz) electrical stimulation in both the external (GPe) and internal (GPi) segments of the globus pallidus was effective in improving parkinsonian motor signs. Improvement generally occurred at short latency (<5-10 seconds) in both GPe and GPi but was often (50% of the time) delayed in GPi. Dyskinetic movements were observed during stimulation within GPe and GPi but were more frequent in GPe (20% vs. 9%). These findings suggest that electrical stimulation in both GPe and GPi may ameliorate parkinsonian motor signs. The mechanisms responsible for these observations, however, may differ. The tendency for delayed responses with GPi stimulation suggests a more complex spatial-temporal profile of stimulation on the electrical activity of GPi neurons and/or its effect on network activity in pallido-thalamo-cortical circuitry. The rarity of delayed effects with GPe stimulation suggests a more direct role of synaptic inhibition or normalization of neuronal activity of GPi either directly by means of activation of striatopallidal fibers passing through GPe (direct pathway), by means of activation of GPe-->GPi or GPe-->subthalamic nucleus projections (indirect pathway) or indirectly by means of the tonic activation of adjacent fiber pathways. These data provide a rationale for the exploration of electrical stimulation in GPe in patients with medically intractable Parkinson's disease and provide a basis on which to develop further investigations into the use of chronic electrical stimulation for the treatment of Parkinson's disease and other movement disorders.

Vitek JL, Bakay RA, Freeman A, Evatt M, Green J, McDonald W, Haber M, Barnhart H, Wahlay N, Triche S, Mewes K, Chockkan V, Zhang JY, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA. · Ann Neurol. · Pubmed #12730989 No free full text.

Abstract: Thirty-six patients with Parkinson's disease (PD) were randomized to either medical therapy (N = 18) or unilateral GPi pallidotomy (N = 18). The primary outcome variable was the change in total Unified Parkinson's Disease Rating Scale (UPDRS) score at 6 months. Secondary outcome variables included subscores and individual parkinsonian symptoms as determined from the UPDRS. At the six month follow-up, patients receiving pallidotomy had a statistically significant reduction (32% decrease) in the total UPDRS score compared to those randomized to medical therapy (5% increase). Following surgery, patients' showed improvement in all the cardinal motor signs of PD including tremor, rigidity, bradykinesia, gait and balance. Drug-induced dyskinesias were also markedly improved. Although the greatest improvement occurred on the side contralateral to the lesion, significant ipsilateral improvement was also observed for bradykinesia, rigidity and drug-induced dyskinesias. A total of twenty patients have been followed for 2 years to assess the effect of time on clinical outcome. These patients have shown sustained improvement in the total UPDRS (p < 0.0001), "off" motor (p < 0.0001) and complications of therapy subscores (p < 0.0001). Sustained improvement was also seen for tremor, rigidity, bradykinesia, percent on time and drug-induced dyskinesias.

Green J, McDonald WM, Vitek JL, Haber M, Barnhart H, Bakay RA, Evatt M, Freeman A, Wahlay N, Triche S, Sirockman B, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, GA 30329, USA. · Neurology. · Pubmed #11914399 No free full text.

Abstract: OBJECTIVE: To evaluate the neuropsychological and psychiatric sequelae of unilateral posterior pallidotomy for treatment of PD. METHODS: Patients with idiopathic PD completed baseline and 3- and 6-month assessments after random assignment to an immediate surgery (n = 17) or medical management (n = 16) group. RESULTS: Compared with the medical management group, the immediate surgery group with single lesions centered on the posterior internal pallidum showed superior naming and response inhibition, better verbal recall at 6 months, but greater distractibility, a tendency toward lower phonemic fluency, and a transient (3 months' only) semantic fluency deficit. The group with left lesions had more neuropsychological deficits than the group with right lesions or the medical management group, although these occurred mainly at 3 (but not 6) months. At 6 months, the patients with left lesions showed better verbal memory retention than the patients with right lesions. On most measures, the pattern of individual clinical change did not differ as a function of surgery or lesion laterality, with the exception of a higher frequency of decline in phonemic fluency in the patients with left lesions at 6 months. Although psychiatric status did not change overall, a history of depression tended to increase the risk of a depressive episode following surgery. CONCLUSIONS: Well-targeted, uncomplicated, unilateral pallidotomy does not produce overall neuropsychological or psychiatric change, although there are subtle changes on specific measures sensitive to frontal lobe function.

Alvarez L, Macias R, Guridi J, Lopez G, Alvarez E, Maragoto C, Teijeiro J, Torres A, Pavon N, Rodriguez-Oroz MC, Ochoa L, Hetherington H, Juncos J, DeLong MR, Obeso JA. · Movement Disorders Clinic and Functional Neurosurgery Service, Centro Internacional de Restauracion Neurologica, La Habana, Cuba. · Mov Disord. · Pubmed #11215596 No free full text.

Abstract: We report our experience of unilateral subthalamotomy in patients with Parkinson's disease (PD). Eleven patients were included in a pilot, open-labeled study to assess the effect of unilateral lesion of the subthalamic nucleus (STN) with a minimum of 12 months of follow-up. The guidelines of CAPIT (Core Assessment Program for Intracerebral Transplantation) were followed for recruitment into the study and follow-up assessment. Levodopa equivalents daily intake (mean 967 mg) were unchanged during the first 12 months in all but one patient who stopped medication. The sensorimotor region of the STN was defined by semimicrorecording and stimulation and a thermolytic lesion was placed accordingly. There was a significant reduction in both UPDRS parts II and III in the "off" state at 1-, 6-, and 12-month follow-up. This effect was maintained in four patients up to 24 months. The dyskinesia score did not change postoperatively. Lesion-induced dyskinesias were not a management problem except in one patient who developed a large infarction several days postsurgery. This initial study indicates that a lesion of the STN is not generally associated with hemiballismus in PD. Subthalamotomy may induce considerable motor benefit and could become another surgical option under specific circumstances.

Epstein CM, Evatt ML, Funk A, Girard-Siqueira L, Lupei N, Slaughter L, Athar S, Green J, McDonald W, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA. · Clin Neurophysiol. · Pubmed #17714987 links to  free full text

Abstract: OBJECTIVE: Major depression is a common concomitant of chronic central nervous system disorders, notably Parkinson's disease (PD). Repetitive transcranial magnetic stimulation (rTMS) has been investigated as a potential treatment for depression in PD and for the movement disorder of PD, but comprehensive testing in multiple areas of performance has seldom been carried out within a single study. We studied the effect of left dorsolateral prefrontal rTMS on several different functional domains. METHODS: Fourteen PD patients with treatment-resistant depression entered an open, 10-day inpatient study of 10-Hz rTMS, undergoing extensive psychiatric, neuropsychological, and motor testing from baseline to 6 weeks after treatment. Motor testing included a defined "off" state. RESULTS: rTMS was well tolerated. Highly significant improvement in depression scores was seen 3 days and 3-6 weeks after treatment. Improvement was also found in anxiety, movement scores (especially in the off state), and some neuropsychological measures. We found no evidence of increased risk from rTMS in this population. CONCLUSIONS: Further controlled trials of rTMS in PD appear worthwhile, and should include a defined "off" state. SIGNIFICANCE: TMS may be beneficial for depressed PD patients in multiple functional domains.

Alvarez L, Macias R, Lopez G, Alvarez E, Pavon N, Rodriguez-Oroz MC, Juncos JL, Maragoto C, Guridi J, Litvan I, Tolosa ES, Koller W, Vitek J, DeLong MR, Obeso JA. · Movement Disorders and Neurophysiology Units, Centro Internacional de Restauracion Neurologica (CIREN), La Habana, Cuba. · Brain. · Pubmed #15689366 links to  free full text

Abstract: We conducted an open label pilot study of the effect of bilateral subthalamotomy in 18 patients with advanced Parkinson's disease. In seven patients, the first subthalamotomy pre-dated the second by 12-24 months ('staged surgery'). Subsequently, a second group of 11 patients received bilateral subthalamotomy on the same day ('simultaneous surgery'). Patients were assessed according to the CAPIT (Core Assessment Program for Intracerebral Transplantation) protocol, a battery of timed motor tests and neuropsychological tests. Evaluations were performed in the 'off' and 'on' drug states before surgery and at 1 and 6 months and every year thereafter for a minimum of 3 years after bilateral subthalamotomy. Compared with baseline, bilateral subthalamotomy induced a significant (P < 0.001) reduction in the 'off' (49.5%) and 'on' (35.5%) Unified Parkinson's Disease Rating Scale (UPDRS) motor scores at the last assessment. A blind rating of videotape motor exams in the 'off' and 'on' medication states preoperatively and at 2 years postoperatively also revealed a significant improvement. All of the cardinal features of Parkinson's disease as well as activities of daily living (ADL) scores significantly improved (P < 0.01). Levodopa-induced dyskinesias were reduced by 50% (P < 0.01), and the mean daily levodopa dose was reduced by 47% at the time of the last evaluation compared with baseline (P < 0.0001). Dyskinesias occurred intraoperatively or in the immediate postoperative hours in 13 patients, but were generally mild and short lasting. Three patients developed severe generalized chorea that gradually resolved within the next 3-6 months. Three patients experienced severe and persistent postoperative dysarthria. In two, this coincided with the patients exhibiting large bilateral lesions also suffering from severe dyskinesias. No patient exhibited permanent cognitive impairment. The motor benefit has persisted for a follow-up of 3-6 years. This study indicates that bilateral subthalamotomy may induce a significant and long-lasting improvement of advanced Parkinson's disease, but the clinical outcome was variable. This variability may depend in large part on the precise location and volume of the lesions. Further refinement of the surgical procedure is mandatory.

Okun MS, Raju DV, Walter BL, Juncos JL, DeLong MR, Heilman K, McDonald WM, Vitek JL. · Department of Neurology, University of Florida McKnight Brain Institute, Gainesville, FL 32610, USA. · J Neurol Neurosurg Psychiatry. · Pubmed #15146017 links to  free full text

Abstract: We describe a case of pseudobulbar crying associated with deep brain stimulation (DBS) in the region of the subthalamic nucleus (STN). Patients with pseudobulbar crying show no other evidence of subjective feelings of depression such as dysphoria, anhedonia, or vegetative signs. This may be accompanied by other symptoms of pseudobulbar palsy and has been reported to occur with ischaemic or structural lesions in both cortical and subcortical regions of the brain. Although depression has been observed to result from DBS in the region of the STN, pseudobulbar crying has not been reported. A single patient who reported the symptoms of pseudobulbar crying after placement of an STN DBS was tested in the off DBS and on DBS conditions. The patient was tested using all four DBS lead contacts and the observations and results of the examiners were recorded. The Geriatric Depression Scale was used to evaluate for depression in all of the conditions. The patient exhibited pseudobulbar crying when on monopolar stimulation at all four lead contacts. The pseudobulbar crying resolved off stimulation. This case describes another type of affective change that may be associated with stimulation in the region of or within the STN. Clinicians should be aware of this potential complication, the importance of differentiating it from stimulation induced depression, and its response to a serotonin reuptake inhibitor, such as sertraline.

Okun MS, DeLong MR, Hanfelt J, Gearing M, Levey A. · Department of Neurology, University of Florida, McKnight Brain Institute, Gainesville 32610, USA. · Neurology. · Pubmed #14872022 No free full text.

Abstract: BACKGROUND: Testosterone deficiency, a treatable condition commonly seen in aging men, has been linked to Parkinson disease (PD) and Alzheimer disease (AD). In normal subjects, low testosterone levels are associated with cognitive and neuropsychiatric symptoms, yet the relationship between testosterone levels and cognitive function in PD and AD remains unclear. OBJECTIVE: To examine the relationship of testosterone levels to age and cognitive function in PD and AD. METHODS: Plasma testosterone levels were determined in men enrolled in a clinical registry of subjects with PD and AD, and neuropsychological testing was performed on subjects who consented. Testosterone levels in men with PD were compared with those in men with AD. In both groups, the relationship between testosterone levels and neuropsychological test scores was analyzed, adjusting for age and education. RESULTS: Linear regression analysis revealed that testosterone levels decreased with age in male PD patients (p < 0.03) and male AD patients (p < 0.07). The rate of decline was similar for the two groups. In PD patients, lower testosterone levels were associated with poorer performance on Trails B Seconds (p < 0.02). CONCLUSIONS: There is a similar age-related decline in plasma testosterone levels in men with either PD or AD. Previously described associations between low testosterone levels and frontal lobe dysfunction in normal aged men, together with these results, suggest that the hormonal deficiency may act as a "second hit" to impair cognitive function in neurodegenerative disease.

Okun MS, Bakay RA, DeLong MR, Vitek JL. · Department of Neurology, University of Florida, Gainesville, FL, USA. · Brain Cogn. · Pubmed #12821111 No free full text.

Abstract: We report two cases of transient hypomanic behavior following pallidotomy. Both of the reported patients had lesions involving non-motor portions of the globus pallidus. Patient 1 had a lesion in the left anteromedial portion of GPi, while patient 2 had one lesion involving the anteromedial portion of GPi on the right and a second lesion involving the postero-ventral most portion of the putamen on the left. These cases emphasize the importance of placing lesions within the sensori-motor portion of GPi without infringing on adjacent non-motor portions. Cases involving transient manic behavior after pallidotomy have not been previously reported. Centers performing pallidotomy or DBS should be aware that lesions or stimulation too anterior in the GPi might lead to manic behavior.

Turner RS, Grafton ST, McIntosh AR, DeLong MR, Hoffman JM. · Department of Neurology, Emory University School of Medicine, WMRB 6000, Atlanta, GA 30322, USA. · Neuroimage. · Pubmed #12781736 No free full text.

Abstract: To investigate the difficulty that patients with Parkinson's disease (PD) have in performing fast movements, we used H(2)(15)O PET to study regional cerebral blood flow (rCBF) associated with performance of a simple predictive visuomanual tracking task at three different velocities. Tracking movements in PD patients (versus tracking with the eyes alone) were associated with a general underactivation of the areas normally activated by the task (sensorimotor cortex contralateral to the moving arm, bilateral dorsal premotor cortices, and ipsilateral cerebellum). Presupplementary motor cortex (pre-SMA) ipsilateral to the moving arm had greater than normal movement-related activations. Increasing movement velocity led to increased rCBF in multiple premotor and parietal cortical areas and basal ganglia in the patients as opposed to the few cerebral locations that are normally velocity-related. The functional correlates of PD bradykinesia are: (1) impaired recruitment of cortical and subcortical systems that normally regulate kinematic parameters of movement such as velocity; and (2) increased recruitment of multiple premotor areas including both regions specialized for visuomotor control (ventral premotor and parietal cortices) and some that are not (pre-SMA). The overactivation of cortical regions observed in patients may be functional correlates of compensatory mechanisms and/or impaired suppression as a facet of the primary pathophysiology of PD.

Okun MS, Walter BL, McDonald WM, Tenover JL, Green J, Juncos JL, DeLong MR. · Department of Neurology, Emory University, Atlanta, Ga., USA. · Arch Neurol. · Pubmed #12433262 links to  free full text

Abstract: OBJECTIVE: To investigate whether a single daily dose of testosterone replacement gel has beneficial effects on testosterone deficiency symptoms, cognitive function, nonmotor symptoms of Parkinson disease (PD), and motor symptoms of PD. BACKGROUND: Recently it has been observed that testosterone replacement therapy improves refractory nonmotor symptoms in testosterone-deficient men with PD. Many of the symptoms of testosterone deficiency are nonspecific and overlap with the nonmotor symptoms of PD, such as decreased enjoyment of life, lack of energy, sexual dysfunction, and depression. Replacement therapy for men with PD and comorbid testosterone deficiency may be an important addition to antiparkinsonian management strategies. METHODS: A prospective open-labeled pilot study of testosterone topical gel (5 g of AndroGel; Unimed Pharmaceutical Inc, Deerfield, Ill) administered daily to testosterone-deficient (free testosterone <80 pg/mL) men with PD. All 10 patients were followed up for 1 month and 6 patients were followed up for a total of 3 months. Patients were administered a battery of testosterone deficiency questionnaires, cognitive studies, and scales of PD nonmotor and motor function at baseline, 1, and 3 months. RESULTS: With the daily transdermal testosterone gel, patients had an average increase in levels of free testosterone from baseline (53 pg/mL) to a 1-month follow-up visit (131 pg/mL; P =.06) and to a 3-month follow-up visit (98 pg/mL; P =.04). Testosterone deficiency symptoms improved in these patients (St Louis Testosterone Deficiency Questionnaire) from baseline (7.9 deficiency symptoms) to 1 month (5.6 deficiency symptoms, P =.04) and 3 months (5.8 deficiency symptoms, P =.08). The Unified Parkinson's Disease Rating Scale IV showed improvement at 1 month (P =.008). Additionally, there were trends toward improvement in the following scales: Unified Parkinson's Disease Rating Scale I at the 3-month follow-up (P =.09), Letter Fluency at the 3-month follow-up (P =.08), and the Hamilton Anxiety Scale at the 1-month follow-up (P =.09). CONCLUSIONS: A daily dose of transdermal testosterone gel improved testosterone deficiency symptoms in men with PD. Although there were trends in improvement in other nonmotor and motor symptoms of PD, future placebo control studies will need to be powered to answer these important questions. Whether testosterone deficiency is simply a comorbidity in PD or whether it plays a role in the pathogenesis of disease also remains for future study.

Green J, McDonald WM, Vitek JL, Evatt M, Freeman A, Haber M, Bakay RA, Triche S, Sirockman B, DeLong MR. · Department of Neurology, Emory University School of Medicine, Emory University, Atlanta, GA, USA. · Neurology. · Pubmed #12427877 No free full text.

Abstract: OBJECTIVE: To determine the nature and frequency of cognitive impairments in nondemented patients with advanced PD and their relationship to other variables potentially predictive of neuropsychological performance. METHODS: The neuropsychological performance of nondemented, nondepressed patients with idiopathic PD (n = 61) was quantified with respect to clinically available normative data. The relationship of neuropsychological measures to motor symptoms, age, years of education, disease duration, age at disease onset, disease deterioration rate, and dopaminergic therapy was assessed. RESULTS: Impairment was most frequent on measures sensitive to frontal lobe function (67% on Wisconsin Card Sorting Test number of categories, 30% on letter fluency, 30% on verbal learning). Poorer performance on multiple neuropsychological measures was related to greater overall motor abnormality (total Unified Parkinson's Disease Rating Scale score), increased bradykinesia on medication, older age, longer disease duration, and reduced education. CONCLUSIONS: Even in the absence of dementia or depression, patients with advanced PD are likely to show clinically significant impairments on neuropsychological measures sensitive to changes in dorsolateral prefrontal regions participating in cognitive basal ganglia-thalamocortical circuits.

Baron MS, Wichmann T, Ma D, DeLong MR. · Department of Neurology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. · J Neurosci. · Pubmed #11784807 links to  free full text

Abstract: Ablative and chronic stimulation procedures targeting the internal pallidum (GPi) and the subthalamic nucleus (STN) have led to major advancements in the treatment of Parkinson's disease and other movement disorders. Although these procedures have evolved to primarily target the posterior ventrolateral sensorimotor portion of GPi and to less selectively target STN, centrally, the ideal targets within these structures remain to be fully established. In this study, we sought to identify the optimal targeting sites in GPi and STN for reversal of parkinsonian signs through a series of reversible injections of the GABA(A) agonist muscimol in these nuclei in parkinsonian primates. Akinesia and bradykinesia were strongly ameliorated by discrete inactivation within the centromedial extent of the sensorimotor territory in GPi and the lateral portion of the sensorimotor territory in STN. This suggests that akinesia and bradykinesia might, in fact, originate from abnormalities in the same, or at least overlapping, motor circuits in the parkinsonian state. Inactivation of areas outside of the motor territories did not improve parkinsonism but induced circling and behavioral abnormalities. The segregation of basal ganglia-thalamocortical circuits appears to be therefore maintained, at least to a large extent, in the parkinsonian state. These results underscore that inactivation of discrete regions in the central territory of GPi and the lateral portion of STN are sufficient to ameliorate parkinsonian motor signs and that extension of lesions into nonmotor territories may be deleterious. Surgical outcomes might therefore be optimized by placing more discrete lesions and by restricting the extent of chronic stimulation.

Okun MS, Stover NP, Subramanian T, Gearing M, Wainer BH, Holder CA, Watts RL, Juncos JL, Freeman A, Evatt ML, Schuele SU, Vitek JL, DeLong MR. · Emory University, Wesley Wood Health Center Building, Third Floor Neurology, 1841 Clifton Rd NE, Atlanta, GA 30329, USA. · Arch Neurol. · Pubmed #11735773 links to  free full text

Abstract: BACKGROUND: Many medical centers throughout the world offer radiosurgery with the gamma knife (GK) for pallidotomy and thalamotomy as a safe and effective alternative to radiofrequency ablative surgery and deep brain stimulation for Parkinson disease (PD). The reported incidence of significant complications varies considerably, and the long-term complication rate remains unknown. DESIGN: We describe 8 patients seen during an 8-month period referred for complications of GK surgery for PD. RESULTS: Of the 8 patients, 1 died as a result of complications, including dysphagia and aspiration pneumonia. Other complications included hemiplegia, homonymous visual field deficit, hand weakness, dysarthria, hypophonia, aphasia, arm and face numbness, and pseudobulbar laughter. In all patients, lesions were significantly off target. CONCLUSIONS: The 8 patients with PD seen in referral at our center for complications of GK surgery highlight a spectrum of potential problems associated with this procedure. These include lesion accuracy and size and the delayed development of neurological complications secondary to radiation necrosis. Gamma knife surgery may have a higher complication rate than has been previously appreciated due to delayed onset and underreporting. We believe that the risk-benefit ratio of the GK will require further scrutiny when considering pallidotomy or thalamotomy in patients with PD. Physicians using this technique should carefully follow up patients postoperatively for delayed complications, and fully inform patients of these potential risks.