Alfonso Fasano

Motor and cognitive outcome in patients with Parkinson's disease 8 years after subthalamic implants.

Deep brain stimulation of the subthalamic nucleus represents the most important innovation for treatment of advanced Parkinsons disease. Prospective studies have shown that although the beneficial effects of this procedure are maintained at 5 years, axial motor features and cognitive decline may occur in the long term after the implants. In order to address some unsolved questions raised by previous studies, we evaluated a series of 20 consecutive patients who received continuous stimulation for 8 years. The overall motor improvement reported at 5 years (55.5% at Unified Parkinsons Disease Rating Scale-motor part, P < 0.001 compared with baseline) was only partly retained 3 years later (39%, P < 0.001, compared with baseline; -16.5%, P < 0.01, compared with 5 years), with differential effects on motor features: speech did not improve and postural stability worsened (P < 0.05). The preoperative levodopa equivalent daily dose was reduced by 58.2% at 5 years and by 60.3% at 8 years. In spite of subtle worsening of motor features, a dramatic impairment in functional state (-56.6% at Unified Parkinsons Disease Rating Scale-Activities of Daily Living, P < 0.01) emerged after the fifth year of stimulation. The present study did not reveal a predictive value of preoperative levodopa response, whereas few single features at baseline (such as gait and postural stability motor scores and the preoperative levodopa equivalent daily dose) could predict long-term motor outcome. A decline in verbal fluency (slightly more pronounced than after 5 years) was detected after 8 years. A significant but slight decline in tasks of abstract reasoning, episodic memory and executive function was also found. One patient had developed dementia at 5 years with further progression at 8 years. Executive dysfunction correlated significantly with postural stability, suggesting interplay between axial motor deterioration and cognition. Eight years after surgery, no significant change was observed on scales assessing depression or anxiety when compared with baseline. At 8 years, there was no significant increase of side-effects when compared with 5-year follow-up. In conclusion, deep brain stimulation of the subthalamic nucleus is a safe procedure with regard to cognitive and behavioural morbidity over long-term follow-up. However, the global benefit partly decreases later in the course of the disease, due to progression of Parkinsons disease and the appearance of medication- and stimulation-resistant symptoms.

Treatment of motor and non-motor features of Parkinson's disease with deep brain stimulation

Deep brain stimulation (DBS) is an established procedure for the symptomatic treatment of Parkinsons disease. Several deep brain nuclei have been stimulated, producing a wide range of effects on the motor and non-motor symptoms of Parkinsons disease. Long-term, high-quality evidence is available for stimulation of the subthalamic nucleus and globus pallidus internus, both of which uniformly improve motor features, and for stimulation of the thalamic ventralis intermedius, which improves tremor. Short-term data are available for stimulation of other deep brain targets, such as the pedunculopontine nucleus and the centremedian/parafascicular thalamic complex. Some non-motor symptoms improve after DBS, partly because of motor benefit or reduction of drug treatment, and partly as a direct effect of stimulation. More evidence on the effects of DBS on non-motor symptoms is needed and specifically designed studies are warranted.

Infection-Triggered Familial or Recurrent Cases of Acute Necrotizing Encephalopathy Caused by Mutations in a Component of the Nuclear Pore, RANBP2

Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur in otherwise healthy children after common viral infections such as influenza and parainfluenza. Most ANE is sporadic and nonrecurrent (isolated ANE). However, we identified a 7 Mb interval containing a susceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2). To determine whether this mutation is the susceptibility allele, we screened controls and other patients with ANE who are unrelated to the index family. Patients from 9 of 15 additional kindreds with familial or recurrent ANE had the identical mutation. It arose de novo in two families and independently in several other families. Two other patients with familial ANE had different RANBP2 missense mutations that altered conserved residues. None of the three RANBP2 missense mutations were found in 19 patients with isolated ANE or in unaffected controls. We conclude that missense mutations in RANBP2 are susceptibility alleles for familial and recurrent cases of ANE.

On state freezing of gait in Parkinson disease: a paradoxical levodopa-induced complication.

Objective: To describe the phenotype of levodopa-induced “on” freezing of gait (FOG) in Parkinson disease (PD). Methods: We present a diagnostic approach to separate “on” FOG (deterioration during the “on state”) from other FOG forms. Four patients with PD with suspected “on” FOG were examined in the “off state” (>12 hours after last medication intake), “on state” (peak effect of usual medication), and “supra-on” state (after intake of at least twice the usual dose). Results: Patients showed clear “on” FOG, which worsened in a dose-dependent fashion from the “on” to the “supra-on” state. Two patients also demonstrated FOG during the “off state,” of lesser magnitude than during “on.” In addition, levodopa produced motor blocks in hand and feet movements, while other parkinsonian features improved. None of the patients had cognitive impairment or a predating “off” FOG. Conclusions: True “on” FOG exists as a rare phenotype in PD, unassociated with cognitive impairment or a predating “off” FOG. Distinguishing the different FOG subtypes requires a comprehensive motor assessment in at least 3 medication states.

The role of small intestinal bacterial overgrowth in Parkinson's disease

Parkinsons disease is associated with gastrointestinal motility abnormalities favoring the occurrence of local infections. The aim of this study was to investigate whether small intestinal bacterial overgrowth contributes to the pathophysiology of motor fluctuations. Thirty‐three patients and 30 controls underwent glucose, lactulose, and urea breath tests to detect small intestinal bacterial overgrowth and Helicobacter pylori infection. Patients also underwent ultrasonography to evaluate gastric emptying. The clinical status and plasma concentration of levodopa were assessed after an acute drug challenge with a standard dose of levodopa, and motor complications were assessed by Unified Parkinsons Disease Rating Scale–IV and by 1‐week diaries of motor conditions. Patients with small intestinal bacterial overgrowth were treated with rifaximin and were clinically and instrumentally reevaluated 1 and 6 months later. The prevalence of small intestinal bacterial overgrowth was significantly higher in patients than in controls (54.5% vs. 20.0%; P = .01), whereas the prevalence of Helicobacter pylori infection was not (33.3% vs. 26.7%). Compared with patients without any infection, the prevalence of unpredictable fluctuations was significantly higher in patients with both infections (8.3% vs. 87.5%; P = .008). Gastric half‐emptying time was significantly longer in patients than in healthy controls but did not differ in patients based on their infective status. Compared with patients without isolated small intestinal bacterial overgrowth, patients with isolated small intestinal bacterial overgrowth had longer off time daily and more episodes of delayed‐on and no‐on. The eradication of small intestinal bacterial overgrowth resulted in improvement in motor fluctuations without affecting the pharmacokinetics of levodopa. The relapse rate of small intestinal bacterial overgrowth at 6 months was 43%.

Management of status dystonicus: Our experience and review of the literature

Status dystonicus (SD) is a life threatening disorder that develops in patients with both primary and secondary dystonia, characterized by acute worsening of symptoms with generalized and severe muscle contractions. To date, no information is available on the best way to treat this disorder. We review the previously described cases of SD and two new cases are reported, one of which occurring in a child with static encephalopathy, and the other one in a patient with pantothenate kinase‐associated neurodegeneration. Both patients were admitted to an intensive care unit and treated with midazolam and propofol. This approach proved to be useful in the former while the progressive nature of the dystonia of the second patient required the combination of intrathecal baclofen infusion and bilateral pallidal deep brain stimulation. We believe that a rapid and aggressive approach is justified to avoid the great morbidity and mortality which characterize SD. Our experience, combined with the data available in the literature, might permit to establish the best strategies in managing this rare and severe condition.

Prevalence of Small Intestinal Bacterial Overgrowth in Parkinson's Disease

Parkinsons disease (PD) is associated with gastrointestinal motility abnormalities that could favor the occurrence of small intestinal bacterial overgrowth. The aim of the study was to assess the prevalence of small intestinal bacterial overgrowth in PD patients.

Gait ataxia in essential tremor is differentially modulated by thalamic stimulation

Patients with advanced stages of essential tremor frequently exhibit tandem gait ataxia with impaired balance control and imprecise foot placement, resembling patients with a cerebellar deficit. Thalamic deep brain stimulation, a surgical therapy for otherwise intractable cases, has been shown to improve tremor, but its impact on cerebellar-like gait difficulties remains to be elucidated. Eleven patients affected by essential tremor (five females; age 69.8 ± 3.9 years; disease duration 24.4 ± 11.2 years; follow-up after surgery 24.7 ± 20.3 months) were evaluated during the following conditions: stimulation off, stimulation on and supra-therapeutic stimulation. Ten age-matched healthy controls served as the comparison group. Locomotion by patients and controls was assessed with (i) overground gait and tandem gait; (ii) balance-assisted treadmill tandem gait and (iii) unassisted treadmill gait. The two treadmill paradigms were kinematically analysed using a 3D opto-electronic motion analysis system. Established clinical and kinesiological measures of ataxia were computed. During stimulation off, the patients exhibited ataxia in all assessment paradigms, which improved during stimulation on and worsened again during supra-therapeutic stimulation. During over ground tandem gait, patients had more missteps and slower gait velocities during stimulation off and supra-therapeutic stimulation than during stimulation on. During balance-assisted tandem gait, stimulation on reduced the temporospatial variability in foot trajectories to nearly normal values, while highly variable (ataxic) foot trajectories were observed during stimulation off and supra-therapeutic stimulation. During unassisted treadmill gait, stimulation on improved gait stability compared with stimulation off and supra-therapeutic stimulation, as demonstrated by increased gait velocity and ankle rotation. These improvements in ataxia were not a function of reduced tremor in the lower limbs or torso. In conclusion, we demonstrate the impact of thalamic stimulation on gait ataxia in patients with essential tremor with improvement by stimulation on and deterioration by supra-therapeutic stimulation, despite continued control of tremor. Thus, cerebellar dysfunction in these patients can be differentially modulated with optimal versus supra-therapeutic stimulation. The cerebellar movement disorder of essential tremor is due to a typical cerebellar deficit, not to trembling extremities. We hypothesize that deep brain stimulation affects two major regulating circuits: the cortico-thalamo-cortical loop for tremor reduction and the cerebello-thalamo-cortical pathway for ataxia reduction (stimulation on) and ataxia induction (supra-therapeutic stimulation).

Long-term outcome of subthalamic nucleus DBS in Parkinson's disease: from the advanced phase towards the late stage of the disease?

BACKGROUND Deep Brain Stimulation of the Subthalamic Nucleus (STN-DBS) is an effective treatment for Parkinsons disease (PD), but only few studies investigated its long-term efficacy. Furthermore, little is known about the role of PD-subtype on STN-DBS long-term outcome. OBJECTIVE To report the results of a long-term follow-up (mean 11 years, range 10-13) on 26 patients bilaterally implanted in two centres. METHODS Patients were assessed preoperatively and 1, 5 and 11 years after the implant by the Unified Parkinsons Disease Rating Scale (UPDRS) and a battery of neuropsychological tests. Stimulation parameters, drugs dosages, non-motor symptoms and adverse events were also recorded. RESULTS At 11 years, stimulation significantly improved the motor symptoms by 35.8%, as compared to the preoperative off-state. Motor complications were well controlled, with a 84.6% improvement of dyskinesias and a 65.8% improvement of motor fluctuations. Despite this, the UPDRS-II-on score worsened by 88.5%, mainly for the worsening of poorly levodopa-responsive symptoms. More than 70% of the patients performed in the normal range in most of the neuropsychological tests, despite the development of dementia in 22.7%. Age at disease onset, axial subscore in off-condition and presence of REM behaviour disorder at baseline were found to be associated with a higher risk of developing disability over time. CONCLUSIONS Our study confirms the long-term safety and efficacy of STN-DBS in PD. Nevertheless, the functionality of patients worsens over time, mainly for the onset and progression of levodopa-resistant and non-motor symptoms. The role of PD-subtype seems to be relevant in the long-term outcome.

Botulinum toxin A versus B in sialorrhea: A prospective, randomized, double-blind, crossover pilot study in patients with amyotrophic lateral sclerosis or Parkinson's disease†

Background: Either botulinum toxins (BoNTs) A and B have been used for improving drooling in different neurological conditions. Methods: Consecutive patients affected by Amyotrophic Lateral Sclerosis (ALS) or Parkinsons Disease (PD) accompanied by severe drooling were randomized to receive botulinum neurotoxin type A (BoNT‐A) or B (BoNT‐B) injections into the salivary glands. Following the first treatment, when sialorrhea returned to baseline (at least three months after the first injection), subjects were re‐treated with the other serotype. Ultrasound‐guided injections into parotid and submandibular glands were bilaterally performed: total doses were 250 U BoNT‐A (Dysport) and 2500 U BoNT‐B (Neurobloc). Objective (cotton roll weight) and subjective (ad hoc clinical scales) evaluations were performed at baseline, after 1 and 4 weeks, and every 4 weeks until drooling returned to baseline. Results: Twenty‐seven patients (15 ALS and 12 PD) were enrolled, fourteen completed the study. BoNT‐A and BoNT‐B treatments gave both subjective and objective improvements in all patients. The latency was significantly shorter after BoNT‐B treatments (3.2 ± 3.7 days) compared to BoNT‐A (6.6 ± 4.1 days; P = 0.002). The mean benefit duration was similar at 75 and 90 days for BoNT‐A and BoNT‐B, respectively (P = NS). The only toxin‐related side effect was a change to saliva thickness. Conclusions: Either 250 U Dysport or 2500 U Neurobloc have similar effectiveness and safety in controlling sialorrhea. BoNT‐B has a shorter latency and comparable duration. Cost analysis, considering the doses used in this study protocol favored BoNT‐B treatment.