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Valerie Voon

Publications and source records attributed to Valerie Voon.

13 recordsLinked to original sources
PubMed2007

Punding prevalence in Parkinson's disease.

The purpose of this study was to determine punding prevalence in an ambulatory Parkinson's disease (PD) population. We conducted a patient-and-caregiver-completed punding survey in 373 consecutive patients in an academic ambulatory center. Completion rate was 78%. Only four patients were identified as punding. Patients did not retain insight to their behavior. Forty patients with high-dose levodopa monotherapy or levodopa and dopamine agonist treatment had physician-administered interview. None had punding. Punding incidence was low in this patient group (1.4%) in contrast with previous reports of 14%. Despite the low incidence, this behavior is disruptive and should be carefully elicited by physicians caring for Parkinson's disease patients.

Aged↗
PubMed2006

Deep brain stimulation: preoperative issues.

Numerous factors need to be taken into account in deciding whether a patient with Parkinson's disease (PD) is a candidate for deep brain stimulation. Patient-related personal factors including age and the presence of other comorbid disorders need to be considered. Neuropsychological and neuropsychiatric concerns relate both to the presurgical status of the patient and to the potential for surgery to result in new problems postoperatively. A number of factors related to the underlying PD need to be considered, including the specific parkinsonian motor indications (e.g., tremor, bradykinesia, gait dysfunction), previous medical therapies, including benefit from current therapy and adverse effects, and past surgical treatments. Definable causes of Parkinsonism, particularly atypical Parkinsonisms, should be considered. Finally, methods of evaluating outcomes should be defined and formalized. This is a report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society (MDS). The report has been endorsed by the Scientific Issues Committee of the MDS and the American Society of Stereotactic and Functional Neurosurgery. It outlines answers to a series of questions developed to address all aspects of deep brain stimulation preoperative decision-making.

Brain↗
PubMed2006

Deep brain stimulation: postoperative issues.

Numerous factors need to be taken into account when managing a patient with Parkinson's disease (PD) after deep brain stimulation (DBS). Questions such as when to begin programming, how to conduct a programming screen, how to assess the effects of programming, and how to titrate stimulation and medication for each of the targeted sites need to be addressed. Follow-up care should be determined, including patient adjustments of stimulation, timing of follow-up visits and telephone contact with the patient, and stimulation and medication conditions during the follow-up assessments. A management plan for problems that can arise after DBS such as weight gain, dyskinesia, axial symptoms, speech dysfunction, muscle contractions, paresthesia, eyelid, ocular and visual disturbances, and behavioral and cognitive problems should be developed. Long-term complications such as infection or erosion, loss of effect, intermittent stimulation, tolerance, and pain or discomfort can develop and need to be managed. Other factors that need consideration are social and job-related factors, development of dementia, general medical issues, and lifestyle changes. This report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society, outlines answers to a series of questions developed to address all aspects of DBS postoperative management and decision-making with a systematic overview of the literature (until mid-2004) and by the expert opinion of the authors. The report has been endorsed by the Scientific Issues Committee of the Movement Disorder Society and the American Society of Stereotactic and Functional Neurosurgery.

Bacterial Infections↗
PubMed2006

Deep brain stimulation: neuropsychological and neuropsychiatric issues.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor, cognitive, neuropsychiatric, autonomic, and other nonmotor symptoms. The efficacy of deep brain stimulation (DBS) for the motor symptoms of advanced PD is well established. However, the effects of DBS on the cognitive and neuropsychiatric symptoms are less clear. The neuropsychiatric aspects of DBS for PD have recently been of considerable clinical and pathophysiological interest. As a companion to the preoperative and postoperative sections of the DBS consensus articles, this article reviews the published literature on the cognitive and neuropsychiatric aspects of DBS for PD. The majority of the observed neuropsychiatric symptoms are transient, treatable, and potentially preventable. Outcome studies, methodological issues, pathophysiology, and preoperative and postoperative management of the cognitive and neuropsychiatric aspects and complications of DBS for PD are discussed.

Cognition Disorders↗
PubMed2006

Pharmacological characterization of psychosis-like behavior in the MPTP-lesioned nonhuman primate model of Parkinson's disease.

Investigation of the pathophysiology of psychosis in Parkinson's disease (PD), as well as the assessment of potential novel therapeutics, has been limited by the lack of a well-validated animal model. MPTP-lesioned primates exhibit abnormal behaviors that are distinct from dyskinesia and parkinsonism and may represent behavioral correlates of neural processes related to psychosis in PD. Here we assess four types of behavior--agitation, hallucinatory-like responses to nonapparent stimuli, obsessive grooming, and stereotypies that are termed "psychosis-like"--and define their pharmacology using a psychosis-like behavior rating scale. By assessing the actions of drugs known to enhance or attenuate psychosis in PD patients, we find that the pharmacology of these behaviors recapitulates, in several respects, the pharmacology of psychosis in PD. Thus, levodopa and apomorphine elicited psychosis-like behaviors. Amantadine significantly decreased levodopa-induced dyskinesia but exacerbated psychosis-like behaviors. Haloperidol reduced psychosis-like behaviors but at the expense of increased parkinsonian disability while the atypical neuroleptics clozapine and quetiapine reduced psychosis-like behaviors without significant effect on parkinsonian disability. The response of different components of the psychotomimetic behavior suggested the involvement of both dopaminergic and nondopaminergic mechanisms in their expression.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2006

Pathological gambling in Parkinson's disease improves on chronic subthalamic nucleus stimulation.

Pathological gambling (PG) related to dopaminergic treatment in Parkinson's disease (PD) is part of a spectrum of behavioral disorders called the dopamine dysregulation syndrome (DDS). We describe a series of PD patients with preoperative active PG due to dopaminergic treatment from a total of 598 patients who have undergone surgery for subthalamic nucleus stimulation for disabling motor fluctuations. The patients had systematic open assessment of behavioral symptoms and standardized assessments of motor symptoms, mood, and apathy. Seven patients (6 men, 1 woman; age, 54 +/- 9 years; levodopa equivalent dose, 1,390 +/- 350 mg/day) had preoperative PG over a mean of 7 years, intolerant to reduction in medication. Six had nonmotor fluctuations and four had other behavioral symptoms consistent with a diagnosis of the DDS. After surgery, motor symptoms improved, allowing for 74% reduction of dopaminergic treatment, below the dosage of gambling onset. In all patients, PG resolved postoperatively after 18 months on average (range, 0-48), although transient worsening occurred in two. Improvement paralleled the time course and degree of reduction in dopaminergic treatment. Nonmotor fluctuations, off period dysphoria, and other symptoms of the DDS improved. Two patients developed persistent apathy. In conclusion, PG and other symptoms of the DDS-associated dopaminergic treatment improved in our patients following surgery. Dopaminergic dysregulation commonly attributed to pulsatile overstimulation of the limbic dopaminergic system may be subject to desensitization on chronic subthalamic stimulation, which has a relative motor selectivity and allows for decrease in dopaminergic treatment.

Adult↗
PubMed2005

Deep brain stimulation for treatment-resistant depression.

Treatment-resistant depression is a severely disabling disorder with no proven treatment options once multiple medications, psychotherapy, and electroconvulsive therapy have failed. Based on our preliminary observation that the subgenual cingulate region (Brodmann area 25) is metabolically overactive in treatment-resistant depression, we studied whether the application of chronic deep brain stimulation to modulate BA25 could reduce this elevated activity and produce clinical benefit in six patients with refractory depression. Chronic stimulation of white matter tracts adjacent to the subgenual cingulate gyrus was associated with a striking and sustained remission of depression in four of six patients. Antidepressant effects were associated with a marked reduction in local cerebral blood flow as well as changes in downstream limbic and cortical sites, measured using positron emission tomography. These results suggest that disrupting focal pathological activity in limbic-cortical circuits using electrical stimulation of the subgenual cingulate white matter can effectively reverse symptoms in otherwise treatment-resistant depression.

Adult↗
PubMed2005

Psychiatric symptoms in patients with Parkinson disease presenting for deep brain stimulation surgery.

OBJECT: Postoperative psychiatric symptoms have been associated with subthalamic deep brain stimulation (DBS) for Parkinson disease (PD), and preoperative psychiatric vulnerability, the effects of surgery, stimulation, medication changes, and psychosocial adjustment have been proposed as causative factors. The variables involved in whether preoperative psychiatric symptoms improve or worsen following surgery are not yet known. In the present study, preoperative psychiatric symptoms were systematically assessed in patients with PD presenting for routine preoperative psychiatric assessment. METHODS: Forty consecutive patients with PD presenting for DBS were interviewed using the Mini International Neuropsychiatric Inventory. Current depressive symptoms were quantified using clinician- and patient-rated depression scales. Seventy-eight percent of patients had at least one lifetime or current Axis I psychiatric diagnosis. The prevalence of depression was 60% (95% confidence interval [CI] 45-85), psychosis 35% (95% CI 25-50), and anxiety 40% (95% CI 25-55). These prevalence rates were comparable to or greater than those in the general population of patients with PD. Twenty-three percent of patients required psychiatric treatment for current symptoms prior to being considered eligible for DBS. CONCLUSIONS: As part of the selection process for surgery, members of the study population were chosen for their lack of overt dementia or other active disabling psychiatric symptomatology. The incidence rates of psychiatric disorders, including those diseases occurring in the general population affected with PD, were greater than expected. Data in the present study lead one to question the reliability of patient-rated depression scales as the sole instrument for assessing depression. The authors highlight the need for evidence-based guidelines in the management of these preoperative symptoms as well as the involvement of psychiatric personnel in the assessment and management of these symptoms.

Aged↗
PubMed2005

Antidepressant treatment outcomes of psychogenic movement disorder.

BACKGROUND: Psychogenic movement disorder (PMD) is a subtype of conversion disorder. We describe the outcomes of a series of PMD patients following antidepressant treatment. METHOD: Twenty-three outpatients with chronic PMD, diagnosed using Fahn and Williams' criteria, underwent psychiatric assessment. The patients were referred for assessment and management from January 2003 to July 2004. Fifteen agreed to be treated with antidepressants. Patients received citalopram or paroxetine; those who did not respond after 4 weeks of taking an optimal dose were switched to venlafaxine. Concurrently, 3 had supportive psychotherapy, and 1 had family intervention. Assessments included the DSM-IV-based Mini-International Neuropsychiatric Interview and scales measuring depression, anxiety, and motor and global severity. RESULTS: Eighteen patients (78%) had at least 1 Axis I diagnosis in addition to the somatoform diagnosis, and 3 (13%) had somatization disorder. Five (22%) had previous psychiatric contact. Nine (39%) had previously been treated with antidepressants, but only 4 (17%) had adequate trials. No significant differences existed in patient characteristics between treated and untreated groups. Among treated patients, Montgomery-Asberg Depression Rating Scale scores improved from baseline (p < .01). Two treated subgroups were identified: 10 patients (67%) had primary conversion disorder, of whom 8 had marked motor and global improvements with 7 complete remissions, and 5 (33%) had primary hypochondriasis, somatization disorder, or probable factitious disorder/malingering, of whom none improved. All of the patients with primary conversion disorder had a current or previous depressive or anxiety disorder compared with 40% (N = 2) of the patients with additional somatoform diagnoses. DISCUSSION: Our preliminary findings suggest that chronic PMD with primary conversion symptoms and with recent or current depression or anxiety may respond to antidepressants. Further well-designed studies, now under way, are required to confirm these findings.

Adult↗
PubMed2005

Psychiatric symptoms following surgery for Parkinson's disease with an emphasis on subthalamic stimulation.

Bilateral subthalamic stimulation is a very effective neurosurgical treatment for advanced Parkinson's disease. Despite the range and frequency of psychiatric symptoms occurring in the postoperative state, most of these symptoms are transient and manageable. In clinical practice, preoperative psychiatric vulnerability, as with that of preoperative cognitive status, takes on an important role. Psychiatric assessment and active preoperative and postoperative intervention can potentially modify psychiatric outcomes. These psychiatric and psychological issues will take on greater importance, particularly with the rapid expansion of the number of neurosurgical sites and the need for adequate assessment and optimal management of patients. The paucity of the literature underscores the need for well-designed studies on psychiatric issues investigating both pathophysiology and clinical outcomes.

Anxiety↗
PubMedDate not supplied

Antidepressants in the treatment of psychosis with comorbid depression in Parkinson disease.

Psychotic symptoms are commonly associated with Parkinson disease and can be a source of significant morbidity. Depression has been reported as a comorbidity in patients with psychosis. We describe a patient with Parkinson disease with psychotic symptoms and comorbid depression whose treatment refractory delusions and hallucinations improved markedly only after antidepressant monotherapy was initiated. The phenomenology of the delusions was atypical for those found in Parkinson or in depression. Psychotic symptoms refractory or only partially responsive to conventional treatment should prompt a search for potential underlying psychiatric comorbidities. Given case reports of exacerbation of psychotic symptoms with antidepressants, we emphasize careful identification and active follow up of the comorbid depressive disorders in PD patients with psychosis. Potential mechanisms implicated in the response of psychosis to antidepressants are discussed.

Antidepressive Agents, Second-Generation↗