Overview of essential tremor

Essential tremor (ET) is one of the most common movement disorders in the world. Despite this, only one medication (propranolol) is approved by the Food and Drug Administration (FDA) to treat it. Fortunately, recent studies have identified some additional medications as treatment of ET. Surgical procedures, such as deep brain stimulation of the ventral intermediate nucleus of the thalamus, offer treatment for refractory tremor. The epidemiology, pathogenesis, and medical and surgical treatment of ET will be discussed in this paper.

Reduction of circulating endothelial cells in peripheral blood of ALS patients

Background

Amyotrophic Lateral Sclerosis (ALS) treatment is complicated by the various mechanisms underlying motor neuron degeneration. Recent studies showed that the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB) are compromised in an animal model of ALS due to endothelial cell degeneration. A later study demonstrated a loss of endothelium integrity in the spinal cords of ALS patients. Since circulating endothelial cells (CECs) in the peripheral blood are associated with endothelium damage, being detached dysfunctional endothelial cells, we hypothesized that CEC levels may reflect endothelium condition in ALS patients.

Methodology/Principal Findings

CEC levels were estimated in whole blood smears from ALS patients with moderate stage (_MALS), severe stage (_SALS), and healthy controls by CD146 expression using immunocytochemistry. A significant reduction of CECs was detected in _MALS and _SALS patients.

Conclusions/Significance

CECs did not predict endothelium state in ALS patients; however, endothelial damage and/or impaired endothelium repair may occur in ALS leading to BBB/BSCB dysfunction. Reduced CECs in peripheral blood of ALS patients may indicate different mechanisms of endothelial damage and repair, rather than only detachment of dysfunctional endothelial cells. Although a potential mechanism of CEC reduction is discussed, establishing a reliable indicator of endothelial dysfunction/damage is important for evaluation of BBB/BSCB status in ALS patients during disease progression.

Practice Parameter: treatment of nonmotor symptoms of Parkinson disease: report of the Quality Standards Subcommittee of the American Academy of Neurology

OBJECTIVE

Nonmotor symptoms (sleep dysfunction, sensory symptoms, autonomic dysfunction, mood disorders, and cognitive abnormalities) in Parkinson disease (PD) are a major cause of morbidity, yet are often underrecognized. This evidence-based practice parameter evaluates treatment options for the nonmotor symptoms of PD. Articles pertaining to cognitive and mood dysfunction in PD, as well as treatment of sialorrhea with botulinum toxin, were previously reviewed as part of American Academy of Neurology practice parameters and were not included here.

METHODS

A literature search of MEDLINE, EMBASE, and Science Citation Index was performed to identify clinical trials in patients with nonmotor symptoms of PD published between 1966 and August 2008. Articles were classified according to a 4-tiered level of evidence scheme and recommendations were based on the level of evidence.

RESULTS AND RECOMMENDATIONS

Sildenafil citrate (50 mg) may be considered to treat erectile dysfunction in patients with Parkinson disease (PD) (Level C). Macrogol (polyethylene glycol) may be considered to treat constipation in patients with PD (Level C). The use of levodopa/carbidopa probably decreases the frequency of spontaneous nighttime leg movements, and should be considered to treat periodic limb movements of sleep in patients with PD (Level B). There is insufficient evidence to support or refute specific treatments for urinary incontinence, orthostatic hypotension, and anxiety (Level U). Future research should include concerted and interdisciplinary efforts toward finding treatments for nonmotor symptoms of PD.

Potential influences of complementary therapy on motor and non-motor complications in Parkinson's disease

Nearly two-thirds of patients with Parkinson's disease (PD) use vitamins or nutritional supplements, and many more may use other complementary therapies, yet <50% of patients have discussed the use of these complementary therapies with a healthcare professional. Physicians should be aware of the complementary therapies their patients with PD are using, and the possible effects of these therapies on motor and non-motor symptoms. Complementary therapies, such as altered diet, dietary supplements, vitamin therapy, herbal supplements, caffeine, nicotine, exercise, physical therapy, massage therapy, melatonin, bright-light therapy and acupuncture, may all influence the symptoms of PD and/or the effectiveness of dopaminergic therapy. Preliminary evidence suggests complementary therapy also may influence non-motor symptoms of PD, such as respiratory disorders, gastrointestinal disorders, mood disorders, sleep and orthostatic hypotension. Whenever possible, clinicians should ensure that complementary therapy is used appropriately in PD patients without reducing the benefits of dopaminergic therapy.

Subjective improvement in proprioception in 2 patients with atypical Friedreich ataxia treated with varenicline (Chantix)

Two patients with atypical Friedreich ataxia (heterozygotes for a GAA expansion and a G130V point mutation) experienced modest proprioceptive improvements in their extremities within a month of taking varenicline (Chantix), a drug approved for smoking cessation.

Treatment of imbalance with varenicline Chantix(R): report of a patient with fragile X tremor/ataxia syndrome

We describe the case of a man with Fragile X tremor/ataxia syndrome, whose ataxia and imbalance improved with the use of varenicline (Chantix) and reverted to baseline 10 days after varenicline was discontinued. Varenicline was started as part of a smoking cessation program.

Sleep disorders in Parkinson's disease

Sleep disorders occur commonly in Parkinson's disease (PD), and reduce quality of life. Sleep-related problems in PD include insomnia, restless legs syndrome, rapid eye movement sleep behavior disorder, sleep apnea, parasomnias, excessive daytime sleepiness, and sleep attacks. This article reviews sleep disorders and their treatment in PD.

A pilot, double-blind, placebo-controlled trial of pregabalin (Lyrica) in the treatment of essential tremor

We performed a pilot, double-blind, placebo-controlled, randomized trial to evaluate the efficacy and tolerability of pregabalin (PGB, Lyrica), an antiepileptic agent, in treating essential tremor (ET). Twenty two patients with ET were randomly assigned to receive PGB or placebo. PGB was initiated at 50 mg/day and was escalated by 75 mg/day every 4 days to a maximum dose of 600 mg/day. Patients were evaluated by accelerometry and the Fahn-Tolosa-Marin (FTM) rating scale. There was a significant reduction in tremor amplitude in the PGB group compared with the placebo group, as measured by accelerometry, at a mean dose of 286.76+/-100.05 mg/day. Action tremor limb scores on the FTM also improved in the PGB group compared with the placebo group (P-value for multilevel modeling=0.04). PGB was fairly well tolerated, with about one-third of patients dropping out of the study because of adverse events. PGB provided significant improvements in accelerometry and in action tremor limb scores on the FTM. However, larger studies are needed to further evaluate the potential effect of PGB on ET.

Levodopa-induced Dyskinesia in Parkinson’s disease: Epidemiology, etiology, and treatment

Although levodopa is the gold standard for treating motor symptoms of Parkinson's disease (PD), long-term therapy leads to levodopa-induced dyskinesia (LID). Dyskinesia refers to involuntary movements other than tremor and most commonly consists of chorea that occurs when levodopa-derived dopamine is peaking in the brain ("peak-dose dyskinesia"). However, dyskinesia can also consist of dystonia or myoclonus and occur during other parts of the levodopa dosing cycle. New validated rating scales and home diaries can better help the health care provider assess the timing and severity of dyskinesia. The exact etiology of LID is unknown, but there is evidence that abnormal pulsatile stimulation of dopamine receptors may be contributory. Treatment of LID includes adjustment of PD medications to maximize "on" time without troublesome dyskinesia. Amantadine is the only medication available with demonstrated ability to reduce the expression of established LID without reducing antiparkinsonian benefit. Other medications that are currently being studied to treat established LID include antiepileptics and serotonergic medications. Deep brain stimulation of the subthalamic nucleus is now the most commonly used surgical procedure for PD patients, and it is very effective in treating LID.

Social Security Disability Insurance (SSDI) in Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) causes significant economic burden for patients and caregivers. Social Security Disability Insurance (SSDI) provides insurance to workers in the United States who have been gainfully employed, but who are no longer able to work due to a medical condition. We performed a descriptive pilot study that examined PD patients' experience with SSDI.

METHODS

PD patients who were diagnosed with PD prior to age 60 and were followed at an academic movement disorders center were consecutively invited to participate in a survey concerning their employment history and experience with SSDI.

RESULTS

All 68 invited patients participated in the study (mean age 58 years, mean disease duration 9.5 years). Eighty-two percent of patients felt that they were too disabled to work full time at a mean of 3.4 years after PD diagnosis. Patients applied for SSDI at a mean of 5 years after diagnosis, and two-thirds of PD patients who applied for SSDI obtained it on their first attempt. The primary debilitating symptom that subjectively contributed to work disability was fatigue (49% of patients). Patients who successfully acquired SSDI had extensive documentation of physician visits, and the aid of a disability lawyer.

CONCLUSIONS

Patients felt they were too disabled to work full time at a mean of 3.4 years after diagnosis. Those who applied for SSDI did so at a mean of 5 years after diagnosis. Patients who obtained SSDI awards had extensive documentation of medical records or the help of a disability lawyer.

Advances in the Pharmacologic Management of Early Parkinson Disease

BACKGROUND

Levodopa, in combination with a dopa decarboxylase inhibitor, provides the greatest symptomatic benefit with the fewest short-term side effects in the treatment of Parkinson disease (PD). However, the disease continues to progress, and the long-term use of levodopa is associated with the development of motor fluctuations and dyskinesias.

REVIEW SUMMARY

Alternatives to the use of levodopa in early PD include monoamine oxidase B (MAO-B) inhibitors, dopamine agonists, and amantadine. Although no medication has been proven to slow the progression of Parkinson disease, preclinical studies have demonstrated neuroprotective effects of MAO-B inhibitors, and a recent study of rasagiline found that PD patients treated with rasagiline for 12 months experienced less progression of symptoms than patients treated with placebo for 6 months followed by rasagiline for 6 months. Several clinical trials have demonstrated that the initial use of a dopamine agonist to which levodopa can be added is associated with fewer motor complications than treatment with levodopa alone. In addition, preclinical studies suggest that adjunctive use of the catechol-O-methyltransferase (COMT) inhibitor entacapone when levodopa is first introduced may be associated with fewer motor complications than treatment with levodopa alone.

CONCLUSION

Treatment of early PD with an MAO-B inhibitor, dopamine agonist, or amantadine, may provide useful alternatives to treatment with levodopa. Adding entacapone at the initiation of levodopa therapy may reduce the development of motor complications. Long-term studies are required to evaluate the potential long-term benefits of these treatment strategies.

A double-blind placebo-controlled trial of zonisamide (zonegran) in the treatment of essential tremor

Medical therapy for essential tremor (ET), a common movement disorder, is often inadequate. We performed a double-blind placebo-controlled randomized trial to evaluate the efficacy and tolerability of zonisamide (ZNS), an antiepileptic agent, in treating ET. Twenty patients (mean age, 60 +/- 15 years) with ET were randomized to receive ZNS or placebo. ZNS was initiated at a dosage of 100 mg/day and escalated to 200 mg/day at day 14. Patients were evaluated by accelerometry and the Fahn-Tolosa-Marin (FTM) rating scale at baseline and days 14 and 28, as well as the Clinical Global Impression (CGI-C) scale at day 28. At endpoint, subjects assigned to ZNS were taking a mean dosage of 160 +/- 50 mg/day. There were no significant improvements in the FTM total score or its subsections. Tremor amplitude as assessed by accelerometry significantly improved in the ZNS group compared to the placebo group at endpoint relative to baseline (-0.50 +/- 0.72 vs. 0.30 +/- 0.79 m/s(2); P = 0.03). On the CGI-C, 60% (n = 6) of patients in the ZNS group felt that their tremor was unchanged, while the remaining patients felt that their tremor was "minimally improved." Thirty percent (n = 3) of patients taking ZNS discontinued the study due to side effects (fatigue, headache, paresthesias) while taking 100 mg per day. ZNS did not provide significant improvements in clinical rating scales at study endpoint compared to placebo and was only modestly well tolerated. ZNS was effective in reducing tremor amplitude as measured by accelerometry.

Pregabalin (Lyrica) in the treatment of essential tremor

We report on 2 essential tremor patients who experienced marked improvement in upper extremity tremor with the use of pregabalin (Lyrica, PGB). On PGB 200 mg/day, tremor amplitude was reduced by at least 40% in the worst affected hand in both patients as measured by accelerometry. Both patients also reported moderate reduction in tremor on the Clinical Global Impression Scale, and Fahn-Tolosa-Marin Part I scores were markedly improved.

Topiramate-induced psychosis in patients with essential tremor: report of 2 cases

Two patients with essential tremor who had no psychiatric history developed symptoms of psychosis (visual hallucinations, paranoia, and vivid dreams) 3 days after starting topiramate (25 mg BID) for tremor control. All adverse symptoms resolved several days after topiramate was discontinued.

Tegaserod (Zelnorm) for the treatment of constipation in Parkinson's disease

We performed a double-blind randomized placebo-controlled pilot study to determine the efficacy of tegaserod (Zelnorm) in treating constipation in 15 patients with Parkinson's disease (PD). There was a trend for improvement in the Subject's Global Assessment (SGA) of satisfaction with bowel habits (NS) and the total SGA (including abdominal discomfort, bothersome constipation, and satisfaction; NS).

Clinical trials aimed at detecting neuroprotection in Parkinson's disease

Potential neuroprotective therapies for Parkinson's disease (PD) are being identified in the laboratory and evaluated in the clinic in an effort to improve long-term outcomes for patients. Several clinical trial designs and methodologies have been used in an attempt to identify neuroprotective effects of medications. Such studies have evaluated (a) time to onset of a clinical milestone of disease progression, (b) progression of clinical symptoms from untreated baseline to an untreated endpoint obtained after wash-out of study intervention, (c) progression of clinical symptoms in early PD, (d) change in imaging markers over time, and (e) a combination of clinical (wash-out) and imaging markers. None of these approaches has yet provided a definitive means to evaluate neuroprotection. Clinical outcomes can be confounded by symptomatic effects of treatments, and imaging markers can be affected by pharmacologic or pharmodynamic changes resulting from treatment. Better methods of assessing putative neuroprotection in PD are needed.