Search

The Parkinson Associated Risk Syndrome (PARS) study was designed to evaluate whether screening with olfactory testing and dopamine transporter (DAT) imaging could identify participants at risk for developing Parkinson's disease (PD).Hyposmia on a single test has been associated with increased risk of PD, but, taken alone, lacks specificity. We evaluated whether repeating olfactory testing improves the diagnostic characteristics of this screening approach.Participants completed up to 10 years of clinical and imaging evaluations in the PARS cohort. Olfaction was assessed with the University of Pennsylvania Smell Identification Test at baseline and on average 1.4 years later. Multiple logistic regression and Cox proportional hazards regression were used to estimate the hazard of development of clinical PD or abnormal DAT imaging.Of 186 participants who were initially hyposmic, 28% reverted to normosmia on repeat testing (reverters). No initially normosmic subjects and only 2% of reverters developed DAT imaging progression or clinical PD, compared to 29% of subjects with persistent hyposmia who developed abnormal DAT and 20% who developed clinical PD. The relative risk of clinical conversion to PD was 8.3 (95% CI:0.92-75.2, p = 0.06) and of abnormal DAT scan was 12.5 (2.4-156.2, p = 0.005) for persistent hyposmia, compared to reversion.Persistent hyposmia on serial olfactory testing significantly increases the risk of developing clinical PD and abnormal DAT imaging, compared to hyposmia on a single test. Repeat olfactory testing may be an efficient and cost-effective strategy to improve identification of at-risk patients for early diagnosis and disease modification studies.

BACKGROUND AND OBJECTIVES The PARS (Parkinson Associated Risk Syndrome) study was designed to test whether screening for hyposmia followed by dopamine transporter imaging can identify risk for conversion to clinical PD, and to evaluate progression markers during the prodromal period. METHODS Subjects with hyposmia completed annual clinical evaluations and biennial [123 I]s-CIT single-photon emission computed tomography scans. Subjects were categorized as normal (>80% age-expected tracer uptake; n = 134), indeterminate (>65-80%; n = 30), and dopamine transporter deficit (≤65%; n = 21) by their baseline scan, and survival analysis was used to compare risk of conversion to motor PD. Progressing to a scan with a dopamine transporter deficit was assessed for those subjects with either normal or indeterminate baseline imaging. RESULTS Over a mean of 6.3 [standard deviation: 2.2] years of follow-up, 67% (n = 14) of dopamine transporter deficit subjects, 20% (n = 6) of dopamine transporter indeterminate subjects, and 4% (n = 6) of dopamine transporter normal subjects converted to a PD diagnosis (P

Restoring function to damaged neural pathways, or promoting compensatory strategies to overcome dysfunctional neural pathways have been topics of inquiry within motor rehabilitation. This study considers these topics in Parkinson’s disease (PD), where disruption within the striatal-thalamic-cortical (STC) circuits can cause impairment in internally guided (IG) movements. A related, but separate externally guided (EG) movement network, recruits the intact cerebellar-thalamic-cortical (CTC) loop to facilitate movement in response to sensory cues, and is effective in remediating motor function. Partnered dance with leading and following roles may be used as proxies for training IG and EG strategies respectively, in PD and can test which strategy is more effective in remediating effects of PD. Leaders determine variables associated with IG and communicate step amplitude, timing, and direction to the follower. Followers use an EG strategy to sense and interpret directional pressure cues from the leader and then enact an appropriate movement response. This study examines how IG and EG training strategy affects STC and CTC circuits and their behavioral outcomes to examine whether compensatory or direct entrainment of neural pathways is more effective in PD. Fifty-eight participants were recruited with mild-moderate PD (stages 1-3) and randomly assigned to EG, IG or non-dance education control group and assessed before and after 12 weeks of biweekly interventions. Participants were assessed with standard cognitive and motor behavioral measures and lay in a Magnetic Resonance Imaging (MRI) scanner while they tapped their foot under two conditions: internal (tapping a learned rhythm: IT) and external (participant taps in response to an assistant’s felt tap on the participant’s hand: ET) guidance. The foot-tapping data collected with an accelerometer were evaluated by analyzing the frequency spectrum to calculate amplitude and timing of the foot taps. The functional (fMRI) data were pre-processed (AFNI), registered (MNI), and analyzed for changes in activation using a general linear model in SAS and AFNI. Postintervention, both the EG and the IG groups showed clinically significant changes on disease severity, but the EG group showed improvements on cognitive, motor, and mood variables. The EG group also outperformed the IG group in the in-scanner task performance measured by the foot accelerometer. Imaging data revealed a significant increase in the EG group in the primary motor cortex lower limb region and the parts of the cerebellar circuits, particularly right Cerebellar Lobule VIIIa. The control group showed an increase in activity in the putamen compared to the IG and EG groups that could be due to a different compensatory pathway. All findings were corroborated using a region of interest approach examining the same pathways according to an atlas. Our results indicate that the most effective strategy for the PD participants involved external cues that increased activity in the compensatory CTC pathway, the primary motor region, and significant improvements on almost all behavioral measurements.

Background: Injectable daxibotulinumtoxinA (an investigational botulinum toxin, RT002) may offer a more prolonged duration of response – and therefore less frequent dosing – than onabotulinumtoxinA. Objectives: To perform a phase 2, open-label, dose-escalation study to assess the efficacy and safety of daxibotulinumtoxinA in cervical dystonia. Methods: Subjects with moderate to severe isolated cervical dystonia were enrolled in sequential cohorts to receive a single open-label, intramuscular dose of injectable daxibotulinumtoxinA of up to 200U (n=12), 200–300U (n=12), or 300–450U (n=13) (clinicaltrials.gov identifier NCT02706795). Results: Overall, 33/37 enrollees completed the trial. DaxibotulinumtoxinA was associated with reductions in Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) Total score of 16.8 (38%) at week 4, 21.3 (50%) at week 6, and 12.8 (30%) at week 24. The proportion of subjects who were responders (achieved ≥ 20% reduction in TWSTRS-Total score) was 94% at week 6 and 68% at week 24. The median duration of response (time until > 20% of the improvement in TWSTRS-Total score achieved at week 4 was no longer retained or re-treatment was needed) was 25.3 weeks (95% CI, 20.14–26.14 weeks). There were no serious adverse events and there was no apparent dose-related increase in the incidence of adverse events. The most common treatment-related adverse events were dysphagia (14%) and injection site erythema (8%). Conclusions: Preliminary assessments suggest that injectable daxibotulinumtoxinA at doses up to 450U is well tolerated and may offer prolonged efficacy in the treatment of cervical dystonia. Further studies involving larger numbers of patients are now warranted. This article is protected by copyright. All rights reserved.

Background An inverse association between Parkinson disease (PD) and total vitamin D levels has been reported but it is unknown whether vitamin D from different sources, i.e. 25(OH)D2 (from diet and supplements) and 25(OH)D3 (mainly from sunlight exposure), all contribute to the association.

Botulinum toxin (BoNT) is highly effective in the treatment of cervical dystonia (CD), yet a significant proportion of patients report low levels of satisfaction following treatment and fail to follow up for repeated treatments. The goal of this study was to determine the reasons that some patients have unsatisfactory responses. A total of 35 subjects who came to our center requesting alternative treatments due to unsatisfactory responses following BoNT treatment for CD were evaluated. Included were 26 women and 9 men with an average age of 57.1 years (range 25-82 years), and an average duration of illness of 12.5 years (range 1-55 years). Details of unsatisfactory BoNT treatments were methodically collected by a movement specialist using a standardized intake form, including provider subspecialty, product used, the number of satisfactory or unsatisfactory trials, doses given, specific muscles treated, the use of electromyographic guidance, side effects, and tests of resistance. The specialist then provided repeat treatments if indicated, and followed each case until the reasons for unsatisfactory outcomes could be determined. Multiple reasons for unsatisfactory outcomes were found. They included suboptimal BoNT doses, suboptimal muscle targeting, intolerable side effects, complex movement patterns, discordant perceptions, and incorrect diagnoses. Only one patient was functionally resistant to BoNT. Of 32 subjects who received repeat BoNT treatments, 25 (78 %) achieved satisfactory responses after revision of the original treatment plan. These results indicate that the majority of unsatisfactory responses to BoNT treatment of CD were caused by correctible factors and imply a need for improved education regarding optimal treatment methods.

Diet therapy for phenylketonuria (PKU) requires restricted phenylalanine (Phe) intake, with the majority of protein and other nutrients coming from synthetic medical food. The fatty acid docosahexaenoic acid (DHA) is important in brain development and function; however, there are reports of low blood DHA concentrations in people treated for PKU. Although the implications of this low blood DHA are unclear, subtle cognitive deficits have been reported in those treated early and continuously for PKU. For this study, we investigated the relationship between DHA status and cognitive performance in 41 females 12 years and older with PKU. Participants were attending the baseline visit of a research-based camp or a supplementation trial. We assessed the domains of verbal ability, processing speed, and executive function using standardized tests, and the proportions of DHA in plasma and red blood cell (RBC) total lipids using gas chromatography/mass spectrometry. Percent plasma and RBC total lipid DHA were significantly lower in the participants compared with laboratory controls (P < .001), and participants consumed no appreciable DHA according to diet records. Plasma and RBC DHA both negatively correlated with plasma Phe (P < .02), and performance on the verbal ability task positively correlated with RBC DHA controlling for plasma Phe (R = .32, P = .03). The relationship between DHA and domains related to verbal ability, such as learning and memory, should be confirmed in a controlled trial. Domains of processing speed and executive function may require a larger sample size to clarify any association with DHA.

OBJECTIVES/SPECIFIC AIMS: Parkinson’s disease (PD) is a condition that affects over a million Americans, and despite current medical therapies, the progression of the disease results in impaired generation of internally timed or guided (IG) movements. To address this loss of motor function, previous rehabilitation therapies have focused on remediating the affected striatal-thalamic-cortical circuits (STC), primarily thought to be responsible in generating timed motor patterns. However, given the disease leads to the cell death of dopaminergic cells that are essential for proper STC function, we propose a motor therapy aimed at utilizing a compensatory parallel cerebellar-thalamic-cortical (CTC) pathway, recruited to perform externally guided (EG) movements, in which gait initiation is driven from sensory input. Our previous study has shown efficacy in our novel argentine tango therapy and improves behavioral measures above the relevant MCID threshold, but it has not been established that the CTC are in the causal pathway that are responsible for these changes. Using neural measures from task fMRI, we have begun to characterize networks that have changed and quantify any associations with behavioral metrics. METHODS/STUDY POPULATION: Patients were randomly assigned to an IG (n=18), EG (n=18), or education contact control (n=14). Participants were assessed preintervention and postintervention for behavioral motor and cognitive measures and neurophysiologically with task based fMRI. In the task, participants performed a foot tapping task under both IG (tap their foot in previously learned rhythm) or EG (tap immediately after receiving a tactile cue on their hand) conditions. The fMRI data were preprocessed using AFNI and registered to MNI standard space. The brainnetome atlas was applied and the average time series of each region of interest (ROI) was used to increase the signal to noise ratio. The activation of these ROI with respect to the stimulus was modeled using GLM, and we estimated the area under the curve during the task blocks. A 1-way ANOVA analysis on these betas were performed between the pre and the post intervention time points and the ROIs that were above a significance of 0.95 were identified and corrected for multiple comparisons. The change in beta in all ROIs for each individual were calculated and then correlated with the changes in the behavioral data, to see which changes in ROI areas matched the best with the behavioral changes. RESULTS/ANTICIPATED RESULTS: The EG group showed significant changes only in the EG task in 2 areas—inferior frontal gyrus and inferior temporal sulcus. Correlating to the cognitive behavioral measures show reduced error from the Inferior frontal gyrus (corr>0.5) best reflect changes in observed. There were no changes to either the STC or the CTC pathways. The IG group showed no changes behaviorally and showed no changes neurally as well. The control group showed no changes behaviorally, but neuronally certain DMN nodes, such as the precuneus and inferior temporal regions showed a significant change for both tasks. DISCUSSION/SIGNIFICANCE OF IMPACT: Addressing the damaged STC pathway directly through IG therapy may not be effective. The EG therapy may not be able to enhance the STC pathway. However, the therapy appears to utilize new areas in the frontal regions and correlates with positively with changes in spatial memory and balance tasks. Contrary to our hypothesis the CTC circuit was not upregulated for performance of the IG or EG task, but therapy may have enhanced recruitment of other cognitively engaged areas. The educational control group interestingly showed changes in the DMN network, which has been shown to be linked to attention during tasks blocks.

ObjectiveTo explore the association between vitamin B12 (B12)-containing supplement use, low B12 concentrations and biochemically defined B12 deficiency in US adults.DesignA cross-sectional study with adjustment for survey design. Prevalence ratios for two age groups (18–50 and >50 years) were estimated using unconditional logistic models. Outcome measures included prevalence of low serum B12 concentration (12 deficiency (serum B12 < 148 pmol/l with concomitant homocysteine > 10 μmol/l).SettingA population survey of health and nutritional measures.SubjectsSubjects were non-institutionalized adults, aged 18 years and older, who participated in Phase 2 of NHANES III (Third National Health and Nutrition Examination Survey).ResultsLow B12 concentrations were less prevalent among persons consuming B12-containing supplements (P = 0·001) with an adjusted prevalence ratio of 0·6 (95 % CI 0·3, 1·0). Biochemical B12 deficiency showed a similar trend (P = 0·0002), with an adjusted prevalence ratio of 0·3 (95 % CI 0·1, 0·8). Prevalence ratios were similar in adults >50 years of age, although the prevalence of low B12 and biochemical deficiency was proportionally higher.ConclusionsConsumption of B12-containing supplements was associated with at least 50 % lower prevalence of both low serum B12 and biochemical B12 deficiency in a nationally representative sample of US adults, suggesting increased consumption of B12 from supplements or from fortified foods may reduce the prevalence of B12 deficiency. Additionally, the current Recommended Daily Allowance for B12 of 2·4 μg may be insufficient for those aged >50 years.

We report 3 cases of impulse control disorders (ICDs) that developed in patients with Parkinson disease treated with the novel dopamine agonist, rotigotine.Three patients were identified retrospectively who developed symptoms of an ICD while taking rotigotine. The ICD symptoms developed at 4, 5, and 8 years after diagnosis of Parkinson disease in these patients and while they were taking rotigotine and levodopa. Other drugs included entacapone, amantadine, and selegiline. The first patient developed symptoms of hypersexuality while taking rotigotine 18 mg (40-cm2 patch) daily and levodopa 300 mg/d. The second patient developed pathological gambling while taking rotigotine 22.5 mg (50-cm2 patch) daily and levodopa 300 mg/d. The third patient developed symptoms of hypersexuality, punding, and pathological gambling, losing more than $100,000 while taking rotigotine 18 mg (40-cm2 patch) and levodopa 400 mg/d. In the first 2 patients, the development of the ICD was temporally associated with an increase in rotigotine dosage, whereas the third patient experienced a dramatic increase in his gambling with the addition of rotigotine. Both subjects who developed pathological gambling had a history of recreational gambling for many years, and 1 of the 2 subjects who developed hypersexuality had a history of cross-dressing since childhood.The ICDs in these patients were effectively treated with rotigotine reduction or discontinuation.Rotigotine has the potential for causing ICD, similar to other dopamine agonists.

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.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.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.Further controlled trials of rTMS in PD appear worthwhile, and should include a defined "off" state.TMS may be beneficial for depressed PD patients in multiple functional domains.

A significant number of patients with Parkinson's disease (PD) experience sialorrhea. This problem can cause social embarrassment, and because saliva pools in the mouth, may lead to aspiration pneumonia. Sialorrhea in PD is thought to be caused by impaired or infrequent swallowing, rather than hypersecretion. Oral medications, botulinum toxin injections, surgical interventions, radiotherapy, speech therapy, and trials of devices may be used to treat sialorrhea in PD, but few controlled trials have been published. This article reviews current knowledge regarding the frequency, etiology, assessment, and treatment of sialorrhea in PD.

Background Dystonia is a neurological disorder characterized by involuntary twisting movements and postures. The neck is among the most commonly affected regions, and diagnosis can be made readily through a simple clinical evaluation. The goal of this study was to explore how long it took patients to receive a diagnosis of cervical dystonia after symptom onset. Methods A structured questionnaire was administered at outpatient clinics of a tertiary care academic medical center to 146 consecutively evaluated patients. The questionnaire addressed the length of time from symptom onset to diagnosis, the numbers and types of providers seen before reaching a diagnosis, and treatments attempted prior to receiving botulinum toxin. Results A total of 108 patients saw a mean of 3.5 providers over a mean period of 44 months from symptom onset to diagnosis. For patients with symptom onset in the last decade only, patients saw a mean of 3.0 providers over a mean of 14 months. Conclusions Although cervical dystonia is the most common form of dystonia with clinical features readily identifiable by a simple history and examination, patients typically see multiple providers over more than a year before reaching a diagnosis and receiving optimal therapy. Improved awareness of the clinical features will enable patients to obtain appropriate therapy more rapidly.

Movement disorders are not particularly common during pregnancy, with a few exceptions. RLS occurs most commonly followed by CG. Currently, with the incidence of rheumatic fever lower than previously, any woman who develops CG should be checked for illness other than rheumatic heart disease. The differential includes systemic lupus erythromatosis and antiphospholipid antibody syndrome. Regarding the use of dopaminergic agents, the dopamine agonist, pergolide, can be maintained during pregnancy for the treatment of PD, Segawa disease, and RLS. The use of levodopa and ropinirole should be limited during pregnancy because of the possible teratogenic effects. Amantadine is contraindicated during pregnancy. The data on selegiline are controversial; animal studies show possible serotonergic effects and teratogenic effects. If treatment is indicated in patients who have Tourette syndrome, the high potency neuroleptics drugs (haloperidol) are preferred to treat associated symptoms. Depression is a common comorbidity in patients who have PD, HD,Tourette syndrome, or other chronic neurologic diseases. Depression treatment during pregnancy is covered by Levy et al elsewhere in this issue. As discussed previously, most of the data on the use of drugs during pregnancy, especially the dopaminergic agents, are limited to animal studies and case reports. Therefore, it is in part left to the neurologist to decide on treatment based on the individual patient, clinical judgment, and inferences from animal studies and limited case reports.

Twenty-nine elderly patients who failed treatment with clozapine, risperidone, or olanzapine entered this 24-week, single-center, open-label trial to assess the efficacy of quetiapine (12.5-400 mg/day) for psychosis in patients with Parkinson's disease (PD). Psychiatric, motor, and cognitive assessments were administered at baseline and at periodic intervals for 24 weeks. These included the Brief Psychiatric Rating Scale (BPRS), Neuropsychiatric Inventory (NPI), Unified Parkinson's Disease Rating Scale (UPDRS) and tests of intellectual functioning, attention, and memory. Repeated measures statistical analysis was used to assess change from baseline. The results revealed significant improvements in the 24-week BPRS total score and NPI psychosis subscale scores, with no decline in UPDRS total or motor subscale scores. There was also significant improvement in recall scores on cognitive measures. These results indicate that quetiapine may treat psychotic symptoms and improve cognition without worsening motor function in patients with PD, suggesting that quetiapine is an effective and well-tolerated antipsychotic in this population.

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.

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.

Objective To evaluate the efficacy of solifenacin succinate in Parkinson's disease (PD) patients suffering from overactive bladder (OAB). Background Urinary dysfunction is a commonly encountered non-motor feature in PD that significantly impacts patient quality of life. Design/methods This was a double-blind, randomized, placebo-controlled, 3-site study with an open label extension phase to determine the efficacy of solifenacin succinate in idiopathic PD patients with OAB. Patients were randomized to receive solifenacin succinate 5–10 mg daily or placebo for 12 weeks followed by an 8-week open label extension. The primary outcome measure was the change in the mean number of micturitions per 24 h period. Secondary outcome measures included the change in the mean number of urinary incontinence episodes and the mean number of nocturia episodes. Results Twenty-three patients were randomized in the study. There was no significant improvement in the primary outcome measure in the double-blind phase, but there was an improvement in the number of micturitions per 24 h period in the solifenacin succinate group compared to placebo at a mean dose of 6 mg/day (p = 0.01). In the open label phase, the mean number of urinary incontinence episodes per 24 h period decreased (p = 0.03), as did the number of nocturia episodes per 24 h period (p = 0.01). Adverse events included constipation and xerostomia, which resolved after treatment was discontinued. Conclusions In this pilot trial, solifenacin succinate treatment led to an improvement in urinary incontinence, despite persistence in other OAB symptoms.

An inverse association between Parkinson disease (PD) and total vitamin D levels has been reported, but whether vitamin D from different sources, that is, 25(OH)D2 (from diet and supplements) and 25(OH)D3 (mainly from sunlight exposure), all contribute to the association is unknown. Plasma total 25(OH)D, 25(OH)D2, and 25(OH)D3 levels were measured by liquid chromatography-tandem mass spectrometry in PD patients (n = 478) and controls (n = 431). Total 25(OH)D was categorized by clinical insufficiency or deficiency; 25(OH)D2 and 25(OH)D3 were analyzed in quartiles. Vitamin D deficiency (total 25[OH]D 20 ng/mL) and vitamin D insufficiency (total 25[OH]D 30 ng/mL) are associated with PD risk (odds ratio [OR] = 2.6 [deficiency] and 2.1 [insufficiency]; P 0.0001), adjusting for age, sex, and sampling season. Both 25(OH)D2 and 25(OH)D3 levels are inversely associated with PD (P(trend) 0.0001). The association between 25(OH)D2 and PD risk is largely confined to individuals with low 25(OH)D3 levels (P(trend) = 0.0008 and 0.12 in individuals with 25[OH]D3 20 ng/mL and 25[OH]D3 ≥ 20 ng/mL, respectively). Our data confirm the association between vitamin D deficiency and PD, and for the first time demonstrate an inverse association of 25(OH)D2 with PD. Given that 25(OH)D2 concentration is independent of sunlight exposure, this new finding suggests that the inverse association between vitamin D levels and PD is not simply attributable to lack of sunlight exposure in PD patients with impaired mobility. The current study, however, cannot exclude the possibility that gastrointestinal dysfunction, a non-motor PD symptom, contributes to the lower vitamin D2 levels in PD patients.

Objective: To evaluate the association between the genetic variants in CACNA1C , which encodes the α1 subunit of the L-type voltage-sensitive calcium channel (LVSCC) and Parkinson disease (PD) while accounting for interactions with vitamin D concentration. Methods: Two independent case-control data sets (478 cases and 431 controls; 482 cases and 412 controls) were used. Joint effects of single nucleotide polymorphisms (SNPs) and SNP-vitamin D interaction were analyzed by comparing models containing vitamin D deficiency, SNP genotypes, SNP-vitamin D interaction, and covariates to a restricted model with only vitamin D deficiency and covariates. Meta-analysis was used to combine the joint effects in the 2 data sets. Analysis was stratified by vitamin D deficiency to demonstrate the pattern of SNP-vitamin D interaction. Results: Vitamin D deficiency was associated with PD in both data sets (odds ratio [OR] = 1.9–2.7, p ≤ 0.009). SNP rs34621387 demonstrated a significant joint effect (meta-analysis, p = 7.5 × 10 −5 ; Bonferroni corrected, p = 0.02). The G allele at rs34621387 is associated with PD in vitamin D-deficient individuals in both data sets (OR = 2.0–2.1, confidence interval = 1.3–3.5, p = 0.002) but is not associated with PD in vitamin D–nondeficient individuals ( p > 0.8 in both data sets). Conclusions: Previous studies suggest that vitamin D deficiency is associated with PD and sustained opening of LVSCC contributes to the selective vulnerability of dopaminergic neurons in PD. Our data demonstrate that the association between genetic variations in CACNA1C and PD depends on vitamin D deficiency, providing one potential mechanism underlying the association between vitamin D deficiency and PD.

To test the association between impaired olfaction and other prodromal features of PD in the Parkinson At-Risk Syndrome Study. The onset of olfactory dysfunction in PD typically precedes motor features, suggesting that olfactory testing could be used as a screening test. A combined strategy that uses other prodromal nonmotor features, along with olfactory testing, may be more efficient than hyposmia alone for detecting the risk of PD. Individuals with no neurological diagnosis completed a mail survey, including the 40-item University of Pennsylvania Smell Identification Test, and questions on prodromal features of PD. The frequency of reported nonmotor features was compared across individuals with and without hyposmia. A total of 4,999 subjects completed and returned the survey and smell test. Of these, 669 were at or below the 15th percentile based on age and gender, indicating hyposmia. Hyposmics were significantly more likely to endorse nonmotor features, including anxiety and depression, constipation, and rapid eye movement sleep behavior disorder symptoms, and to report changes in motor function. Twenty-six percent of subjects with combinations of four or more nonmotor features were hyposmic, compared to 12% for those reporting three or fewer nonmotor features (P < 0.0001). Hyposmia is associated with other nonmotor features of PD in undiagnosed individuals. Further assessment of hyposmic subjects using more specific markers for degeneration, such as dopamine transporter imaging, will evaluate whether combining hyposmia and other nonmotor features is useful in assessing the risk of future neurodegeneration.

Low blood docosahexaenoic acid (DHA) is reported in patients with phenylketonuria (PKU); however, the functional implications in adolescents and adults are unknown. This pilot study investigated the effect of supplemental DHA on cognitive performance in 33 females with PKU ages 12–47 years. Participants were randomly assigned to receive DHA (10 mg/kg/day) or placebo for 4.5 months. Performance on cognitive processing speed and executive functioning tasks was evaluated at baseline and follow up. Intention-to-treat and per protocol analyses were performed. At follow up, biomarkers of DHA status were significantly higher in the DHA-supplemented group. Performance on the cognitive tasks and reported treatment-related adverse events did not differ. While no evidence of cognitive effect was seen, a larger sample size is needed to be conclusive, which may not be feasible in this population. Supplementation was a safe and effective way to increase biomarkers of DHA status (www.clinicaltrials.gov; Identifier: NCT00892554).

Dystonia is defined as involuntary sustained muscle contractions producing twisting or squeezing movements and abnormal postures. The movements can be stereotyped and repetitive and they may vary in speed from rapid to slow; sustained contractions can result in fixed postures. Dystonic disorders are classified into primary and secondary forms. Several types of adult-onset primary dystonia have been identified but all share the characteristic that dystonia (including tremor) is the sole neurologic feature. The forms most commonly seen in neurological practice include cranial dystonia (blepharospasm, oromandibular and lingual dystonia and spasmodic dysphonia), cervical dystonia (also known as spasmodic torticollis) and writer's cramp. These are the disorders that benefit most from botulinum toxin injections. A general characteristic of dystonia is that the movements or postures may occur in relation to specific voluntary actions by the involved muscle groups (such as in writer's cramp). Dystonic contractions may occur in one body segment with movement of another (overflow dystonia). With progression, dystonia often becomes present at rest. Dystonic movements typically worsen with anxiety, heightened emotions, and fatigue, decrease with relaxation, and disappear during sleep. There may be diurnal fluctuations in the dystonia, which manifest as little or no involuntary movement in the morning followed by severe disabling dystonia in the afternoon and evening. Morning improvement (or honeymoon) is seen with several types of dystonia. Patients often discover maneuvers that reduce the dystonia and which involve sensory stimuli such as touching the chin lightly in cervical dystonia. These maneuvers are known as sensory tricks, or gestes antagonistes. This chapter focuses on adult-onset focal dystonias including cranial dystonia, cervical dystonia, and writer's cramp. The chapter begins with a review of the epidemiology of focal dystonias, followed by discussions of each major type of focal dystonia, covering clinical phenomenology, differential genetics, and diagnosis. The chapter concludes with discussions of the pathophysiology, the few pathological cases published of adult-onset focal dystonia and management options, and a a brief look at the future.

Vitamin D insufficiency has been reported to be more common in patients with Parkinson disease (PD) than in healthy control subjects, but it is not clear whether having a chronic disease causing reduced mobility contributes to this relatively high prevalence.To examine the prevalence of vitamin D insufficiency in a cohort of untreated patients with early PD (diagnosed within 5 years of study entry). DESIGN, SETTING, AND PATIENTS The Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) cohort is a well-characterized cohort of subjects with early, nondisabling PD. The cohort is well suited for examining the prevalence of vitamin D insufficiency early in the course of the disease. We conducted a survey study of vitamin D status in stored blood samples from patients with PD enrolled in the placebo group of the DATATOP trial. Samples from baseline visits and end point/final visits (mean [SD], 18.9 [13.1] months) were analyzed for 25-hydroxyvitamin D (25[OH]D) concentration in blinded fashion.The mean vitamin D concentration and the prevalence of vitamin D insufficiency at baseline and end point/final visits.Among 199 subjects, 170 (85.4%) had samples from the baseline and end point visits available for analysis; 13 were excluded (10 with low probability of having PD and 3 with 25[OH]D concentrations3 SDs above the mean). In the remaining 157 subjects, the mean (SD) 25(OH)D concentrations at the baseline and end point visits were 26.3 (8.6) ng/mL and 31.3 (9.0) ng/mL, respectively (to convert to nanomoles per liter, multiply by 2.496). The prevalence of vitamin D insufficiency (25[OH]D concentration30.0 ng/mL) was 69.4% at baseline and 51.6% at the end point.The prevalence of vitamin D insufficiency in patients with early PD was similar to or higher than those reported in previous studies. Vitamin D concentrations did not decline during progression of PD. Further studies are needed to elucidate the natural history and significance of vitamin D insufficiency in PD.

Dystonia is defined as involuntary sustained muscle contractions producing twisting or squeezing movements and abnormal postures. The movements can be stereotyped and repetitive and they may vary in speed from rapid to slow; sustained contractions can result in fixed postures. Dystonic disorders are classified into primary and secondary forms. Several types of adult-onset primary dystonia have been identified but all share the characteristic that dystonia (including tremor) is the sole neurologic feature. The forms most commonly seen in neurological practice include cranial dystonia (blepharospasm, oromandibular and lingual dystonia and spasmodic dysphonia), cervical dystonia (also known as spasmodic torticollis) and writer's cramp. These are the disorders that benefit most from botulinum toxin injections. A general characteristic of dystonia is that the movements or postures may occur in relation to specific voluntary actions by the involved muscle groups (such as in writer's cramp). Dystonic contractions may occur in one body segment with movement of another (overflow dystonia). With progression, dystonia often becomes present at rest. Dystonic movements typically worsen with anxiety, heightened emotions, and fatigue, decrease with relaxation, and disappear during sleep. There may be diurnal fluctuations in the dystonia, which manifest as little or no involuntary movement in the morning followed by severe disabling dystonia in the afternoon and evening. Morning improvement (or honeymoon) is seen with several types of dystonia. Patients often discover maneuvers that reduce the dystonia and which involve sensory stimuli such as touching the chin lightly in cervical dystonia. These maneuvers are known as sensory tricks, or gestes antagonistes. This chapter focuses on adult-onset focal dystonias including cranial dystonia, cervical dystonia, and writer's cramp. The chapter begins with a review of the epidemiology of focal dystonias, followed by discussions of each major type of focal dystonia, covering clinical phenomenology, differential genetics, and diagnosis. The chapter concludes with discussions of the pathophysiology, the few pathological cases published of adult-onset focal dystonia and management options, and a a brief look at the future.

Evaluate the safety and efficacy of a sequential dose escalation of rimabotulinumtoxinB (BoNT-B) in cervical dystonia (CD) subjects.This multicenter, open-label, within-subject, sequential dose-escalation study (BoNT-B dosed at 10,000, 12,500, and 15,000 Units) evaluated subjects over each phase of treatment at preinjection and at periodic intervals postinjection. Adverse events, vital signs, and laboratory results were recorded. Efficacy measures included the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and three visual analog scales (VASs).119 out of 145 CD subjects received all three doses in sequence. Dry mouth and dysphagia were the most common adverse events, and both decreased in frequency by the final injection, despite the increasing doses of the escalation. TWSTRS-Total and subscale scores demonstrated significant improvements following all doses at the week 2, 4, 8, and 12 assessments, with the exception of disability and pain at week 12 with the lowest dose. All VAS scores demonstrated similar improvements following all doses. The mean number of weeks in each phase of the study was 12.1 weeks (10,000 Units), 12.9 weeks (12,500 Units), and 13.9 weeks (15,000 Units).BoNT-B was well tolerated and efficacious at 10,000, 12,500, and 15,000 Units in this within-subject, sequential dose-escalation study in CD subjects.

Nearly two-thirds of patients with Parkinson's disease (PD) use vitamins or nutritional supplements, and many more may use other complementary therapies, yet

Upper and lower gastrointestinal dysautonomia symptoms (GIDS)--sialorrhea, dysphagia, and constipation are common in Parkinson's disease (PD) and often socially as well as physically disabling for patients. Available invasive quantitative measures for assessing these symptoms and their response to therapy are time-consuming, require specialized equipment, can cause patient discomfort and present patients with risk. The Movement Disorders Society commissioned a task force to assess available clinical rating scales, critique their clinimetric properties, and make recommendations regarding their clinical utility. Six clinical researchers and a biostatistician systematically searched the literature for scales of sialorrhea, dysphagia, and constipation, evaluated the scales' previous use, performance parameters, and quality of validation data (if available). A scale was designated "Recommended" if the scale was used in clinical studies beyond the group that developed it, has been specifically used in PD reports, and clinimetric studies have established that it is a valid, reliable, and sensitive. "Suggested" scales met at least part of the above criteria, but fell short of meeting all. Based on the systematic review, scales for individual symptoms of sialorrhea, dysphagia, and constipation were identified along with three global scales that include these symptoms in the context of assessing dysautonomia or nonmotor symptoms. Three sialorrhea scales met criteria for Suggested: Drooling Severity and Frequency Scale (DSFS), Drooling Rating Scale, and Sialorrhea Clinical Scale for PD (SCS-PD). Two dysphagia scales, the Swallowing Disturbance Questionnaire (SDQ) and Dysphagia-Specific Quality of Life (SWAL-QOL), met criteria for Suggested. Although Rome III constipation module is widely accepted in the gastroenterology community, and the earlier version from the Rome II criteria has been used in a single study of PD patients, neither met criteria for Suggested or Recommended. Among the global scales, the Scales for Outcomes in PD-Autonomic (SCOPA-AUT) and Nonmotor Symptoms Questionnaire for PD (NMSQuest) both met criteria for Recommended, and the Nonmotor Symptoms Scale (NMSS) met criteria for Suggested; however, none specifically focuses on the target gastrointestinal symptoms (sialorrhea, dysphagia, and constipation) of this report. A very small number of rating scales have been applied to studies of gastrointestinal-related dysautonomia in PD. Only two scales met "Recommended" criteria and neither focuses specifically on the symptoms of sialorrhea, dysphagia, and constipation. Further scale testing in PD among the scales that focus on these symptoms is warranted, and no new scales are needed until the available scales are fully tested clinimetrically.

Background A role for vitamin D deficiency in Parkinson disease (PD) has recently been proposed. Objective To compare the prevalence of vitamin D deficiency in a research database cohort of patients with PD with the prevalence in age-matched healthy controls and patients with Alzheimer disease (AD). Design Survey study and blinded comparison of plasma 25-hydroxyvitamin D (25[OH]D) concentrations of stored samples in a clinical research database at Emory University School of Medicine. Setting Referral center (PD and AD patients), primary care clinics, and community setting (controls). Participants Participants were recruited into the study between May 1992 and March 2007. Every fifth consecutively enrolled PD patient was selected from the clinical research database. Unrelated AD (n = 97) and control (n = 99) participants were randomly selected from the database after matching for age, sex, race, APOE genotype, and geographic location. Main Outcome Measures Prevalence of suboptimal vitamin D and mean 25(OH)D concentrations. Results Significantly more patients with PD (55%) had insufficient vitamin D than did controls (36%) or patients with AD (41%; P = .02, χ 2 test). The mean (SD) 25(OH)D concentration in the PD cohort was significantly lower than in the AD and control cohorts (31.9 [13.6] ng/mL vs 34.8 [15.4] ng/mL and 37.0 [14.5] ng/mL, respectively; P = .03). Conclusions This report of 25(OH)D concentrations in a predominantly white PD cohort demonstrates a significantly higher prevalence of hypovitaminosis in PD vs both healthy controls and patients with AD. These data support a possible role of vitamin D insufficiency in PD. Further studies are needed to determine the factors contributing to these differences and elucidate the potential role of vitamin D in pathogenesis and clinical course of PD.

Advise patients with Parkinson's disease (PD) to consume a balanced diet, with special attention to adequate intake of dietary fiber, fluids, and macro- and micronutrients. Regularly reassess patients' nutritional history and anthropomorphic measures (height and weight), particularly in patients with advanced disease. PD-related psychosocial as well as physical and cognitive limitations increase susceptibility to subacute and chronic malnutrition. Nutritional requirements may change with PD progression or after surgical therapy for PD. Patients and caregivers may benefit from counseling by a dietician who is knowledgeable about the nutritional risks and needs of PD. Regularly inquire about dysphagia symptoms, and consider speech therapy consultation for clinical and modified barium-swallowing evaluations and management recommendations. Although non-oral delivery options of dopaminergic therapy are increasing, severe dysphagia may warrant percutaneous endoscopic gastrostomy tube placement for nutritional support and more reliable PD medication dosing. Analyze vitamin B(12) and D concentrations at regular intervals. Both vitamins are frequently deficient in elderly persons but may not be routinely checked by primary care physicians. Record over-the-counter and nutritional supplement medications at each visit, and assist patients in periodically re-evaluating their potential benefits, side effects, drug interactions, and costs. To date, clinical trials of antioxidant vitamins and nutritional supplements have provided insufficient evidence to support routine use for PD in the clinic. Data from several clinical trials of antioxidant vitamins/nutritional supplements are expected in the near future. Consider altering medication dosing in relation to meals to help with mild to moderate motor fluctuations. Patients with severe motor fluctuations may benefit from adapting the 5:1 carbohydrate-to-protein ratio in their daily meals and snacks. Following a "protein redistribution" diet is logistically more difficult and less palatable, and therefore less frequently recommended. To ensure adequate protein intake, a registered dietician should supervise patients who follow either of these diets.

Little is known regarding the effects of antiparkinsonian drugs in US racial or ethnic minorities.: To evaluate the safety, tolerability, and efficacy of adjunctive pramipexole in Parkinson disease (PD) patients of African, Asian, or Hispanic heritage stably treated with levodopa.Multicenter, parallel-group, double-blind, randomized, placebo-controlled trial.: Seventeen Parkinson Study Group sites in the United States and Puerto Rico.One hundred forty-four PD patients of African, Asian, or Hispanic heritage enrolled from January 1997 to August 1998 and observed until October 1998.Subjects received pramipexole or placebo (3:1 ratio), 0.375 mg/d to a maximum tolerated dose (or=4.5 mg/d) over a 6-week period, achieving optimum levels (0.375, 1.5, 3.0, or 4.5 mg/d) in the 4-week maintenance period.Change in the sum of the Unified Parkinson's Disease Rating Scale parts 2 (activities of daily living) and 3 (motor) from baseline to week 10.Parkinsonism improved (mean [SD] reduction in Unified Parkinson's Disease Rating Scale activities of daily living + motor score at 10 weeks, 10.27 [11.96] pramipexole vs 6.54 [13.58] placebo, P = 0.012) and was similar in each group. Adverse events occurred in 85.3% on pramipexole and 68.6% on placebo. Hallucinations and insomnia were more common on pramipexole than placebo (18 vs 0, P = 0.023, and 15 vs 0, P = 0.045, respectively).Pramipexole is an effective adjunctive antiparkinsonian therapy in PD patients of African, Asian, and Hispanic heritage. Tolerability and safety overall were similar among the groups, but differences in profiles of adverse effects and tolerability were suggested.

Background The preferred surgical target for the treatment of Parkinson disease (PD) is either the internal globus pallidus or the subthalamic nucleus (STN); the target for treatment of essential tremor (ET) is the thalamic subnucleus ventralis intermedius (Vim). Some patients with PD have coexistent ET, and the identification of a single surgical target to treat both parkinsonian motor symptoms and ET would be of practical importance. Objective To describe the use of the STN target in deep brain stimulator (DBS) surgery to treat PD motor symptoms and the action-postural tremor of ET. Design Case report. Patient A 62-year-old man had a greater than 30-year history of action-postural tremor in both hands, well controlled with β-blockers for more than 20 years. He developed resting tremor, bradykinesia, and rigidity on his right side that progressed to his left side during the past 10 years. Dopaminergic medication improved his rigid-ity and bradykinesia, with only mild improvement of his resting tremor and no effect on his action-postural tremor. Interventions Left pallidotomy followed by placement of a left DBS in the Vim and subsequent placement of a right STN DBS. Main Outcome Measures Control of symptoms of PD and ET. Results The left pallidotomy controlled the patient’s parkinsonian motor symptoms on the right side of his body, but did not affect the action-postural component of his tremor. The symptoms on the left side of the body, including both an action-postural and a resting tremor (as well as the rigidity and bradykinesia), improved after placement of a single right STN DBS. Conclusion Placement of an STN DBS should be considered as the procedure of choice for surgical treatment of patients with a combination of PD and ET.

Increasing evidence suggests that Parkinson disease (PD) should be included on the growing list of diseases associated with vitamin D insufficiency. A recent study reconfirms this association and supports the monitoring of vitamin D concentrations in patients with PD. The conundrum of causality regarding this association, however, remains unanswered.

Twenty-nine elderly patients who failed treatment with clozapine, risperidone, or olanzapine entered this 24-week, single-center, open-label trial to assess the efficacy of quetiapine (12.5-400 mg/day) for psychosis in patients with Parkinson's disease (PD). Psychiatric, motor, and cognitive assessments were administered at baseline and at periodic intervals for 24 weeks. These included the Brief Psychiatric Rating Scale (BPRS), Neuropsychiatric Inventory (NPI), Unified Parkinson's Disease Rating Scale (UPDRS) and tests of intellectual functioning, attention, and memory. Repeated measures statistical analysis was used to assess change from baseline. The results revealed significant improvements in the 24-week BPRS total score and NPI psychosis subscale scores, with no decline in UPDRS total or motor subscale scores. There was also significant improvement in recall scores on cognitive measures. These results indicate that quetiapine may treat psychotic symptoms and improve cognition without worsening motor function in patients with PD, suggesting that quetiapine is an effective and well-tolerated antipsychotic in this population.

Importance Coenzyme Q10 (CoQ10), an antioxidant that supports mitochondrial function, has been shown in preclinical Parkinson disease (PD) models to reduce the loss of dopamine neurons, and was safe and well tolerated in early-phase human studies. A previous phase II study suggested possible clinical benefit. Objective To examine whether CoQ10 could slow disease progression in early PD. Design, Setting, and Participants A phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites consisting of participants 30 years of age or older who received a diagnosis of PD within 5 years and who had the following inclusion criteria: the presence of a rest tremor, bradykinesia, and rigidity; a modified Hoehn and Yahr stage of 2.5 or less; and no anticipated need for dopaminergic therapy within 3 months. Exclusion criteria included the use of any PD medication within 60 days, the use of any symptomatic PD medication for more than 90 days, atypical or drug-induced parkinsonism, a Unified Parkinson’s Disease Rating Scale (UPDRS) rest tremor score of 3 or greater for any limb, a Mini-Mental State Examination score of 25 or less, a history of stroke, the use of certain supplements, and substantial recent exposure to CoQ10. Of 696 participants screened, 78 were found to be ineligible, and 18 declined participation. Interventions The remaining 600 participants were randomly assigned to receive placebo, 1200 mg/d of CoQ10, or 2400 mg/d of CoQ10; all participants received 1200 IU/d of vitamin E. Main Outcomes and Measures Participants were observed for 16 months or until a disability requiring dopaminergic treatment. The prospectively defined primary outcome measure was the change in total UPDRS score (Parts I-III) from baseline to final visit. The study was powered to detect a 3-point difference between an active treatment and placebo. Results The baseline characteristics of the participants were well balanced, the mean age was 62.5 years, 66% of participants were male, and the mean baseline total UPDRS score was 22.7. A total of 267 participants required treatment (94 received placebo, 87 received 1200 mg/d of CoQ10, and 86 received 2400 mg/d of CoQ10), and 65 participants (29 who received placebo, 19 who received 1200 mg/d of CoQ10, and 17 who received 2400 mg/d of CoQ10) withdrew prematurely. Treatments were well tolerated with no safety concerns. The study was terminated after a prespecified futility criterion was reached. At study termination, both active treatment groups showed slight adverse trends relative to placebo. Adjusted mean changes (worsening) in total UPDRS scores from baseline to final visit were 6.9 points (placebo), 7.5 points (1200 mg/d of CoQ10; P = .49 relative to placebo), and 8.0 points (2400 mg/d of CoQ10; P = .21 relative to placebo). Conclusions and Relevance Coenzyme Q10 was safe and well tolerated in this population, but showed no evidence of clinical benefit. Trial Registration clinicaltrials.gov Identifier:NCT00740714

Recent clinical evidence supports a link between 25-hydroxyvitamin D insufficiency (serum 25-hydroxyvitamin D [25(OH)D] levels

We find the report by Bromley et al.1 of an increased incidence of autism spectrum disorders in the offspring of mothers taking antiepileptic drugs (AEDs) during pregnancy intriguing and suggest low vitamin D as a possible mechanism deserving further investigation. Several AEDs are known to bind to the pregnane X receptor to increase the catabolism of vitamin D by upregulating the mitochondrial enzyme CYP24. AEDs, including valproic acid, are known to decrease 25-hydroxyvitamin D levels.2 It has been reported that babies born to women taking AEDs during pregnancy had significantly lower 25-hydroxyvitamin D concentrations compared to healthy control newborns.3 Vitamin …

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.

Modulation of the human spinal stretch reflex (SSR) may be important in treating hyperactive reflexes or may be a tool to enhance normal performance. Eight of 9 subjects given feedback of biceps brachii SSR amplitude and instructed to increase (uptrain) or decrease (downtrain) this response were able to do so in the appropriate direction. These results imply that, as in non-human primates, SSR amplitude can be modified.