Showing papers by "Kapil D. Sethi published in 2005"

The role of radiotracer imaging in Parkinson disease

Abstract: Radiotracer imaging (RTI) of the nigrostriatal dopaminergic system is a widely used but controversial biomarker in Parkinson disease (PD). Here the authors review the concepts of biomarker development and the evidence to support the use of four radiotracers as biomarkers in PD: [ 18 F]fluorodopa PET, (+)-[ 11 C]dihydrotetrabenazine PET, [ 123 I]β-CIT SPECT, and [ 18 F]fluorodeoxyglucose PET. Biomarkers used to study disease biology and facilitate drug discovery and early human trials rely on evidence that they are measuring relevant biologic processes. The four tracers fulfill this criterion, although they do not measure the number or density of dopaminergic neurons. Biomarkers used as diagnostic tests, prognostic tools, or surrogate endpoints must not only have biologic relevance but also a strong linkage to the clinical outcome of interest. No radiotracers fulfill these criteria, and current evidence does not support the use of imaging as a diagnostic tool in clinical practice or as a surrogate endpoint in clinical trials. Mechanistic information added by RTI to clinical trials may be difficult to interpret because of uncertainty about the interaction between the interventions and the tracer.

Identification of motor and nonmotor wearing-off in Parkinson's disease: comparison of a patient questionnaire versus a clinician assessment.

Abstract: This study compares the sensitivity of a Patient Questionnaire versus information gathered by clinicians at a routine clinic visit in recognizing symptoms of wearing-off in early Parkinson's disease (PD). This Patient Questionnaire, containing 32 items representing a wide spectrum of motor and nonmotor wearing-off symptoms, was administered to subjects attending two PD clinics. The Patient Questionnaire results were compared to the information gathered by the clinician from the Unified Parkinson's Disease Rating Scale (UPDRS) Part IV, Question 36 and from a specific Clinical Assessment Question regarding loss of medication efficacy, wearing-off, sleepiness, dyskinesias, psychiatric complications, morning akinesia, other dopaminergic side effects, or none of the above. Examiners were blinded to study hypothesis and survey contents. Three hundred consecutive subjects with PD of <5 years duration were evaluated; the mean subject age was 72 +/- 9.6 years and 60.2% were men. Subjects reporting wearing-off were significantly younger (69.9 vs. 74.7 years) and differed regarding duration of PD symptoms (3.7 vs. 3.1 years). Wearing-off was found in 181 subjects (62.6%) by one or more of the three measures. The most sensitive tool was the Patient Questionnaire, with 165 subjects (57.1%) indicating symptoms of wearing-off. Question 36 of the UPDRS was positive in 127 subjects (43.9%), and the Clinical Assessment Question identified 85 subjects (29.4%) as experiencing wearing-off. All of these results were found to differ significantly. The mean number of wearing-off symptoms reported by the 165 subjects indicating wearing-off on the clinical survey was 6.25, with tremor being the most common motor feature and tiredness the most common nonmotor feature.

Drug-induced tremors

Abstract: Summary Tremor is a common complaint for many patients. Caffeine and β-adrenergic agonists are well-recognised drugs that cause or exacerbate tremors. Other tremorogenic drugs, such as selective serotonin reuptake inhibitors and tricyclic antidepressants, are less well recognised. Recognition of the drugs that can cause or exacerbate tremors can help prompt diagnosis, avoids unnecessary tests, and allows clinicians to quickly take corrective action (usually by discontinuing the tremor-inducing drugs). The aim of this review is to provide clinicians with current information on drugs that are associated with tremor and the correct treatment of these drug-induced tremors.

Psychogenic paroxysmal dyskinesia following paroxysmal hemidystonia in multiple sclerosis

Abstract: A 27-year-old woman presented because of multiple daily episodes of painful “drawing” in her right arm and leg precipitated by hyperventilation (see video, segment 1). These episodes would typically last between 30 seconds and 2 minutes. Brain MRI and CSF analysis were consistent with multiple sclerosis (MS). MS-related paroxysmal hemidystonia was diagnosed because of a typical pattern of limb …

Progression of dystonia in complex regional pain syndrome [1] (multiple letters)

Abstract: To the Editor: Oaklander’s report1 of a patient with complex regional pain syndrome (CRPS) in addition to a movement disorder is an excellent example of the value of videotape publications. The patient is described as having progressive right lower extremity dystonia and tremor in the contralateral foot. That the movements began abruptly after vein stripping is stated as evidence that neither psychological factors nor disuse could have caused the movements, hence their organic nature as part of CRPS. Psychogenic movement disorders can be difficult to diagnose and neurologists and other physicians are often reluctant to make the diagnosis despite well-established criteria.2-4 In contrast to Oaklander’s claim, the abrupt onset of a movement disorder is a clue about a psychogenic etiology, as is adult-onset dystonia beginning in the lower extremity. Another clue is the presence of more than one movement disorder. Furthermore, there is controversy about the organic etiology of posttraumatic movement disorders, such as following vein stripping. The videotape provides additional evidence: the patient exhibits a fixed dystonic posture of the right foot (another feature suggestive of psychogenic dystonia) with an atypical low amplitude, high frequency tremor of the involved foot (not typical of dystonic tremor) and an equally atypical “bouncy” whole-leg tremor of the contralateral lower extremity. The historical and physical features of this patient support a psychogenic movement disorder. This report should not be used as evidence that movement disorders are an accepted part of the complex regional pain syndrome.

Absorption of orally disintegrating carbidopa-levodopa requires intact small bowel function.

Abstract: Orally disintegrating tablet (ODT) technology is used in multiple pharmaceuticals.1 ODT carbidopa-levodopa (CD-LD) was introduced in 2004, and while this formulation is a more convenient dosing option for some patients, it still requires absorption in the proximal small intestine as does standard CD-LD. We report two patients with PD in whom ODT CD-LD was inappropriately used in the setting of paralytic ileus. ### Case 1. A 63-year-old woman with Parkinson disease (PD) for 8 years treated with standard CD-LD was admitted for cholecystectomy. Her postoperative course was complicated by paralytic ileus and encephalopathy, likely from sedative drugs. She was given ODT CD-LD during this period for her PD. We were consulted for worsening parkinsonism despite the patient taking an equivalent CD-LD preoperative dose in the form of ODT CD-LD. Our examination revealed global bradykinesia, marked cogwheel rigidity, and profound hypomimia. Once the ileus resolved, the patient resumed her preoperative dose of standard CD-LD and within 2 weeks she had returned to …

Throat clicking as the initial symptom of Parkinson's disease.

Abstract: The presenting manifestations of Parkinson's disease (PD) are variable, but a majority of patients note tremor as the initial symptom. Others complain of slowing of movements, loss of dexterity, fatigue, or changes in handwriting as initial symptoms. We describe a patient who developed an unusual clicking sound emanating from his throat as the initial manifestation of PD.