Phenomenology and treatment of tremor disorders

Tremor is classified according to anatomic distribution among body parts, and by frequency and amplitude during rest, postural maintenance, movement, intention, and the performance of specific tasks. Key historical features include age at onset, progression over time, family history, exacerbating and remitting factors and behaviors, response to alcohol and medications, and additional neurological signs and symptoms. Accurate diagnosis is a critical factor in predicting the natural history and response to treatment.

Pramipexole-induced somnolence and episodes of daytime sleep

Pramipexole is a non-ergot dopamine agonist used to treat Parkinson's disease (PD). Because of concern regarding driving safety, we evaluated the incidence and nature of somnolence experienced by patients receiving pramipexole in clinical trials at our center. A retrospective chart review was performed and structured interviews were conducted with patients who had reported moderate or severe somnolence. In addition, two patients underwent polysomnography (PSG) and multiple sleep latency tests (MSLT) while on and 2 weeks after discontinuation of pramipexole. Forty patients with PD participating in pramipexole clinical trials were identified. In the double-blind phases of the studies, 22 patients were randomized to pramipexole and 18 were randomized to placebo. Six patients assigned to pramipexole reported somnolence as an adverse event (1 moderate, 5 mild) compared with two patients assigned to placebo (1 severe, 1 moderate; p = 0.19, one-tailed Fisher's exact test). Thirty-seven patients participated in open-label extension studies. Twenty-one (57%) reported somnolence as an adverse event. Eleven (30%) patients reported moderate somnolence and three (8%) patients reported severe somnolence. For patients with moderate or severe somnolence, the onset of worst-reported somnolence occurred at a mean (+/- standard error) pramipexole dose of 4.0 +/- 0.4 mg (range, 0.75-4.5 mg) per day. Patients had been taking pramipexole for a total of 10.0 +/- 1.5 months (range, .03-22 mos) and at their maximal dose for 6.7 +/- 1.5 months (range, .03-20 mos). During structured interviews with 12 of the 14 patients reporting moderate or severe somnolence, seven reported falling asleep while driving and two reported minor motor vehicle accidents caused by falling asleep. Most patients reported relatively continuous drowsiness that led to falling asleep without acute warning during periods of inactivity. Three patients reported discreet waves of irresistible sleepiness heralded by prodromal symptoms occurring against a background of normal wakefulness. MSLT in two of these patients revealed decreased latency to sleep without early onset of rapid eye movements. Sleep latency normalized after withdrawal of pramipexole. Intensive patient education is necessary to prevent motor vehicle accidents in patients taking pramipexole. We recommend that patients who are experiencing generalized drowsiness and falling asleep during periods of inactivity be instructed not to drive because these patients do fall asleep without acute warning. Somnolence usually resolves with pramipexole dose reduction or discontinuation. Patients should also be alerted to pull over and stop driving immediately if they feel a wave of sleepiness coming on. Patient education and compliance are critical to maximize safety.

Current issues in depression in Parkinson's disease

Depression affects 40%-50% of Parkinson's disease (PD) patients. The authors, by use of a Mednet and manual search of pertinent literature, summarize current issues in the treatment of depression in PD. Open-label studies suggest that antidepressants may be effective for treating depression in PD. Although case reports indicate that selective serotonin reuptake inhibitors (SSRIs) can potentially worsen the motor symptoms of PD, this effect has not been confirmed in the small number of open-label studies that have been performed to date. The occurrence of the serotonin syndrome resulting from a combination of selegiline and an SSRI appears to be rare. Double-blind prospective studies are needed to evaluate the safety and efficacy of antidepressants in PD and their effect on motor function.

Sildenafil citrate (Viagra) for the treatment of erectile dysfunction in men with Parkinson's disease

Sildenafil citrate (Viagra) is a phosphodiesterase type V inhibitor used to treat erectile dysfunction. Ten men with idiopathic Parkinson's disease (PD) and erectile dysfunction were prescribed 50-100 mg sildenafil citrate to use in eight sexual encounters over a 2-month period. Patients underwent Unified Parkinson's Disease Rating Scale (UPDRS) evaluations and completed a Beck's Depression Inventory (BDI) and a Sexual Health Inventory-M version (SHI-M) at baseline and after 8 weeks. There was statistically significant improvement in total SHI-M scores (23.8 +/- 2.0 vs 16.6 +/- 2.8; p = 0.01), overall sexual satisfaction (p = 0.03), satisfaction with sexual desire (p = 0.04), ability to achieve erection (p = 0.02), ability to maintain erection (p = 0.03), and ability to reach orgasm (p = 0.04) with use of sildenafil citrate. UPDRS and BDI scores were not significantly changed. Side effects included headache in one patient during three sexual encounters. In this open-label study, sildenafil citrate significantly improved sexual function in men with PD and erectile dysfunction.

A home diary to assess functional status in patients with Parkinson's disease with motor fluctuations and dyskinesia

In clinical trials for patients with Parkinson's disease (PD) with motor fluctuations, efficacy is generally ascribed to an intervention if motor function is significantly improved or if "off" time is significantly reduced. However, we have argued that patients might not be improved if off time is reduced only to the extent that unwanted dyskinesia is increased. Therefore, a home diary should include an assessment of dyskinesia to provide an accurate reflection of clinical status over a period of time. We undertook two studies to develop a home diary to assess functional status in patients with PD with motor fluctuations and dyskinesia. In both studies, patients concurrently completed a test and a reference diary. In Study I, we evaluated the impact of different severities of dyskinesia on patient-defined functional status. There were 1,149 evaluable half-hour time periods from 24 patients; 94.3% of off time was considered "bad" time and 90.2% of "on" time without dyskinesia, 72.6% of on time with mild dyskinesia, 43.0% of on time with moderate dyskinesia, and 15.2% of on time with severe dyskinesia was considered "good" time. In Study II, we evaluated a new home diary designed to separate dyskinesia that had a negative impact on patient-defined functional status from dyskinesia that did not. There were 816 evaluable time periods from 17 patients; 84.9% of off time and 89.9% of on time with troublesome dyskinesia was considered bad time while 85.5% of on time without dyskinesia and 93.8% of on time with nontroublesome dyskinesia was considered good time. With this diary (Diary II), the effect of an intervention can be expressed as the change in off time and the change in on time with troublesome dyskinesia (bad time). The sum can be used as an outcome variable and compared to baseline or across groups. In evaluating the efficacy of an intervention, assessment of change in off time and change in on time with troublesome dyskinesia provides a more accurate reflection of clinical response than change in off time alone.

Management of early Parkinson's disease

The two major questions in the treatment of early PD are (1) Does selegiline slow neuronal loss and delay the progression of clinical disability? and (2) Should dopamine agonists be used as initial symptomatic therapy in early disease rather than levodopa/PDI to reduce long-term disability and delay the onset of motor fluctuations and dyskinesia? Selegiline affords neuroprotection for dopamine neurons in cell culture systems and the results of several clinical trials are consistent with the hypothesis that it is neuroprotective in Parkinson's disease. Several clinical trials have found that initial symptomatic therapy with dopamine agonist to which levodopa/carbidopa is later added when needed leads to a lower incidence of long-term motor complications. These strategies are now being tested in prospective, randomized, blinded trials, many of which include PET or SPECT scans to assess the rate of dopamine neuron loss. These trials will provide more definitive answers to guide the early medial management of Parkinson's disease in the future.

Sertraline for the treatment of depression in Parkinson's disease

Although antidepressant medications are commonly used to treat depression in Parkinson's disease (PD), little information is available regarding their safety and efficacy in this condition. Sertraline is a relatively selective serotonin reuptake inhibitor with some dopamine reuptake inhibitor activity. It has a favorable tolerability profile, especially in the elderly. We undertook an open-label pilot evaluation of the safety and efficacy of sertraline to treat depression in PD. A total of 15 patients with PD and depression participated in the study. Sertraline was introduced at a daily dose of 25 mg for 1 week and then increased to 50 mg/day. Patients underwent evaluation at baseline and at a final visit approximately 7 weeks later. Sertraline was generally well tolerated, but five patients experienced side effects, and two discontinued medication. Patients taking selegiline experienced more adverse effects. Beck Depression Inventory scores improved significantly (mean +/- SE = 16.0 +/- 2.0 vs 11.7 +/- 1.9, p = 0.03), and Unified Parkinson's Disease Rating Scale and energy-level scores were unchanged. These results suggest that sertraline may be a useful treatment for depression in PD. As substantial placebo effects can occur in studies of PD and depression, placebo-controlled, double-blind studies are warranted.

Blood manganese correlates with brain magnetic resonance imaging changes in patients with liver disease

BACKGROUND

Chronic liver failure is associated with high signal abnormalities in the basal ganglia on T1-weighted magnetic resonance imaging of the brain. These abnormalities are strikingly similar to those seen following manganese intoxication. As dietary manganese is normally cleared by the liver, we hypothesize that hepatic dysfunction could lead to manganese overload and account for the MRI abnormalities seen in patients with chronic liver disease.

METHODS

We measured blood manganese concentrations in eleven patients with biopsy-proven hepatic cirrhosis and eleven healthy age and sex-matched controls. We also performed semi-quantitative measures of T1 signal abnormalities on MRI in the patients with chronic liver disease.

RESULTS

Patients with cirrhosis had significantly higher blood manganese concentrations (20.6 +/- 10.2 mcg/L) than controls (7.2 +/- 2.7, p = .0013). In addition, semi-quantitative scores of T1-weighted signal hyperintensity on MRI correlated with blood manganese concentration in patients with cirrhosis (r = .65, p = .029).

CONCLUSIONS

These findings demonstrate that chronic liver disease is associated with manganese overload and suggest that manganese is responsible for the T1-weighted signal hyperintensity seen on MRI of patients with liver disease. As manganese intoxication is known to cause parkinsonism and an encephalopathy similar to those which occur with chronic liver disease, it is possible that manganese toxicity contributes to the development of these symptoms in liver damaged patients and that therapies which prevent or reduce manganese overload may have clinical benefit.

Manganese intoxication and chronic liver failure

Manganese intoxication and chronic liver failure are associated with strikingly similar clinical, imaging, and pathological abnormalities. As manganese is primarily cleared by the liver, inadequate elimination of manganese absorbed from the normal diet may lead to manganese overload in patients with liver disease. We report a significant elevation of blood manganese concentration in 3 patients with biopsy-proved hepatic cirrhosis who exhibited neurological dysfunction and characteristic abnormal signal hyperintensity in the globi pallidi and substantia nigra on T1-weighted magnetic resonance imaging. We speculate that manganese accumulation in the brain accounts for the magnetic resonance imaging abnormalities and contributes to neurological dysfunction in patients with liver disease.

Clinical predictors of abnormality disclosed by computed tomography after mild head trauma

We prospectively studied 712 consecutive patients during a 1-year period who presented with amnesia or loss of consciousness after nonpenetrating head trauma and who had a perfect Glasgow Coma Scale score of 15. Of the 67 (9.4%) patients with acute traumatic lesions disclosed by computed tomography (CT) of the head, 2 required neurosurgical intervention and 1 died. Four factors were statistically correlated (P < 0.05) with abnormal CT findings: Older age, white race, signs of basilar skull fracture, and being either a pedestrian hit by a motor vehicle or a victim of an assault. Sex, length of antero- or retrograde amnesia, forward and reverse digit spans, object recall, focal abnormality on the general neurological exam, and subjective complaints were not statistically correlated with CT abnormality. Using step-wise discriminant function analysis, no single item or combination of items could be used to classify 95% of the patients into either the normal or abnormal CT group. Therefore, regardless of age, mechanism of injury, or clinical findings, intracranial lesions cannot be completely excluded clinically on head-trauma patients who have loss of consciousness or amnesia, even if the Glasgow Coma Scale score is 15. However, only two patients (0.3%) required neurosurgical intervention.