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Biomedical subjects

Ali Samii

Publications and source records attributed to Ali Samii.

30 records · Page 2Linked to original sources

Complex regional pain syndrome as a stress response.

A man in his 50's with a prior traumatic brain injury and multiple psychiatric disorders developed acute pain and swelling in his left leg distal to the mid shin. These symptoms arose during an exacerbation of his post-traumatic stress disorder (PTSD). Among his traumatic memories, he reported having witnessed the combat injury and death of a friend who had lost his left leg distal to the mid shin. A diagnosis of conversion disorder was technically excluded because the findings met criteria for Complex Regional Pain Syndrome (CRPS) type I. Based on recent research into the neurobiology of CRPS, PTSD and conversion disorder, we propose a supraspinal mechanism which could explain how emotional stress can produce both symptoms and signs.

Antidepressive Agents↗

Mechanical failure of the electrode wire in deep brain stimulation.

The feasibility and efficacy of deep brain stimulation (DBS) has offered new possibilities for treatment of movement disorders. Mechanical failure of the DBS system is a potential complication. Here we report five patients who presented with mechanical failure of the DBS system. Radiographs of the skull and cervical spine were analyzed for disruptions. Seven instances of lead breakage near the connection of the DBS electrode with the extension wire were identified. In one patient this was in the paramastoid area over the skull, while in all others were in the supraclavicular location. The patients consisted of three men and two women ranging in age from 24 to 78 (at the time of first operation), one person suffering three breakages. The length of spanned time from implantation to presentation ranged from 8 to 32 months. Palpation of the electrode lead wire in the neck for breakage proved unreliable. Radiography localized the site of breakage in all but one patient who required intraoperative exploration, which revealed that although the lead wire was disrupted, the two ends remained in contact. The fact that all breakages occurred near the connection wire suggests that to-and-fro motion of the DBS electrode with repeated head turning leads to fatigue and eventual disruption.

Adult↗

Delayed onset of ataxia in a patient with short bowel syndrome: a case of vitamin E deficiency.

Chronic gastrointestinal disease can result in nutritional deficiencies that can have a direct effect on the neurologic system. Although acute abnormalities can be corrected, symptoms are rarely reversible. Recognizing the appropriate abnormality is a crucial part of long-term treatment strategies in this population. Because motor and cerebellar symptoms can contribute to poor feeding, aggressive supplementation should begin as soon as symptoms are recognized. We present a patient with delayed onset and progressive hypovitaminosis E and briefly review diagnostic and therapeutic options.

Ataxia↗

Pharmacoepidemiology I: a review of pharmacoepidemiologic study designs.

This article is the first of two parts on pharmacoepidemiology, a relatively new science that explores drug efficacy or toxicity using large observational study designs. The number of pharmacoepidemiologic studies published in medical journals has increased, as these studies have explored drug-related questions that at times cannot be answered in randomized clinical trials. Four pharmacoepidemiologic study designs will be discussed that explore the association between a specific pharmacologic agent and a disease of interest: cohort studies, case-control studies, case-crossover studies, and case-time-control studies.

Case-Control Studies↗

Effect of non-steroidal anti-inflammatory drugs on risk of Alzheimer's disease: systematic review and meta-analysis of observational studies.

OBJECTIVES: To quantify the risk of Alzheimer's disease in users of all non-steroidal anti-inflammatory drugs (NSAIDs) and users of aspirin and to determine any influence of duration of use. DESIGN: Systematic review and meta-analysis of observational studies published between 1966 and October 2002 that examined the role of NSAID use in preventing Alzheimer's disease. Studies identified through Medline, Embase, International Pharmaceutical Abstracts, and the Cochrane Library. RESULTS: Nine studies looked at all NSAIDs in adults aged > 55 years. Six were cohort studies (total of 13 211 participants), and three were case-control studies (1443 participants). The pooled relative risk of Alzheimer's disease among users of NSAIDs was 0.72 (95% confidence interval 0.56 to 0.94). The risk was 0.95 (0.70 to 1.29) among short term users (< 1 month) and 0.83 (0.65 to 1.06) and 0.27 (0.13 to 0.58) among intermediate term (mostly < 24 months) and long term (mostly > 24 months) users, respectively. The pooled relative risk in the eight studies of aspirin users was 0.87 (0.70 to 1.07). CONCLUSIONS: NSAIDs offer some protection against the development of Alzheimer's disease. The appropriate dosage and duration of drug use and the ratios of risk to benefit are still unclear.

Aged↗

Bilateral subthalamic nucleus stimulation after bilateral pallidotomies in a patient with advanced Parkinson's disease.

A 54-year-old man with advanced Parkinson's disease (PD) presented to our institution in early 2000. He had undergone a right pallidotomy in 1994, a left pallidotomy in 1996, and bilateral subthalamic nucleus (STN) electrode implants in 1999. The patient had cervical myelopathy for which he had undergone neck surgery in 1998. We used the Unified Parkinson's Disease Rating Scale (UPDRS) to evaluate motor performance in four states: combinations of stimulation OFF or ON and medication OFF or ON. There was no significant change in motor UPDRS scores with STN stimulation or with medications. Multiple attempts to optimize stimulation parameters and medication dosages did not result in significant and sustained improvement in activities of daily living or motor performance. To our knowledge, this is the first reported case of bilateral STN stimulation after bilateral pallidotomies. The presence of cervical myelopathy and the limited response to anti-Parkinson medications in this patient underscores the importance of patient selection for functional neurosurgery in PD.

Electric Stimulation Therapy↗

The youngest reported case of corticobasal degeneration.

Corticobasal degeneration (CBD) is a movement disorder characterized by early apraxia and asymmetric parkinsonism that responds poorly to anti-Parkinson medications. There are clinical manifestations reflecting dysfunction in both the cerebral cortex and the basal ganglia. Patients typically present between the sixth and seventh decades. Previously, the youngest clinically diagnosed individual was 40 years old. Here we describe a 34-year-old woman who meets the clinical diagnostic criteria for CBD with onset of symptoms at age 28. In this patient, the first symptom was an 'uncooperative' right hand. This was soon followed by right hand dystonia. Symptoms progressed rapidly, and she developed generalized bradykinesia, rigidity, and corticospinal tract signs with preservation of the initial asymmetry. Her symptoms did not respond to a daily dose of 1200 mg of immediate release levodopa. Extensive laboratory workup and brain imaging were normal. Neuropsychological evaluation revealed mild deficits consistent with frontal-subcortical dysfunction. The chronic, progressive course, asymmetric limb rigidity, apraxia, focal dystonia, and lack of response to levodopa suggest CBD. To our knowledge, this is the youngest reported case of clinically probable CBD.

Adult↗

The role of lipid-lowering drugs in cognitive function: a meta-analysis of observational studies.

STUDY OBJECTIVE: To quantify the risk of cognitive impairment with use of lipid-lowering drugs. DESIGN AND DATA SOURCES: Literature search through MEDLINE and EMBASE databases; data from seven observational studies were analyzed. MEASUREMENTS AND MAIN RESULTS: We quantified the risk of cognitive impairment first with the use of any lipid-lowering drug, and then specifically with the statins, using the random effects model. We tested for heterogeneity using the Q statistic as well as quantitatively using the Ri statistic. All seven studies provided data for statin users, and five provided data only on use of lipid-lowering drugs. Compared with patients not receiving lipid-lowering drugs, the relative risk of cognitive impairment with any lipid-lowering drug was 0.62 but was not statistically significant (95% confidence interval [CI] 0.28-1.38), and the relative risk with statins was 0.43 and was statistically significant (95% CI 0.31-0.62). CONCLUSION: Lipid-lowering drugs--in particular, the statins--seem to lower the odds of developing cognitive impairment. Randomized, controlled trials are needed to address the efficacy of these agents specifically in different types of dementia.

Cognition↗

Comparison of the risk of adverse events with pramipexole and ropinirole in patients with Parkinson's disease: a meta-analysis.

BACKGROUND: Pramipexole and ropinirole are relatively new dopamine agonists, both of which have proven efficacy in the treatment of Parkinson's disease. There is, however, uncertainty regarding differences in the adverse event profiles associated with each drug. OBJECTIVE: To compare the adverse events of pramipexole and ropinirole as reported in the peer-reviewed medical literature. METHODS: We systematically reviewed the medical literature to identify randomised controlled trials of pramipexole and ropinirole used in the management of Parkinson's disease. Computerised databases (including Medline, Embase, the Cochrane Library, and the International Pharmaceutical Abstracts) were used to identify pertinent articles for inclusion in this study. Trials that compared the dopamine agonists to either levodopa or placebo were included. ANALYSIS: Adverse events with these drugs included dizziness, nausea, hypotension, hallucinations, and somnolence. We made two separate analyses. In the first analysis, we estimated the pooled relative risk (RR) of adverse events with either pramipexole or ropinirole as compared with levodopa. In the second analysis, the pooled RRs of adverse events with pramipexole and ropinirole were compared with placebo. We used the random-effects model of DerSimonian and Laird to estimate the RRs and their corresponding 95% CIs. We tested for study heterogeneity using Q statistics. RESULTS: There was no significant difference in the risk of dizziness, nausea, or hypotension with either drug individually or in combination when compared with levodopa. The risk of hypotension was approximately four times higher with ropinirole than pramipexole when each drug was individually compared with placebo (6.46 [95% CI 1.47-28.28] for ropinirole, and 1.65 [0.88-3.08] for pramipexole). The pooled RR (for pramipexole and ropinirole combined) of hallucinations was 1.92 (95% CI 1.08-3.43) when compared with levodopa. Relative to placebo, pramipexole had a significantly higher risk of hallucinations than ropinirole (pramipexole 5.2 [95% CI 1.97-13.72] vs ropinirole 2.75 [95% CI 0.55-13.73]). There was no significant difference in the risk of somnolence between the two drugs when each was individually compared with levodopa. When compared with placebo, the pooled RR (pramipexole and ropinirole combined) of somnolence was 3.16 (95% CI 1.62-6.13). Relative to placebo, the risk of somnolence was 2.01 (95% CI 2.17-3.16) with pramipexole and 5.73 (95% CI 2.34-14.01) with ropinirole. CONCLUSIONS: Use of ropinirole seems to be associated with a higher risk of hypotension and somnolence than use of pramipexole when compared with placebo. Use of pramipexole seems to be associated with a higher risk of hallucinations than use of ropinirole when compared with placebo.

Adverse Drug Reaction Reporting Systems↗

[18F]-Dopa positron emission tomography imaging in early-stage, non-parkin juvenile parkinsonism.

There are few reports of positron emission tomography (PET) in juvenile parkinsonism (JP). We report on the results of (18)F-6-fluoro-L-dopa (FD) PET in a 14-year-old patient with JP of 5 years duration associated with atypical features. This is the youngest subject to be investigated to date. There was a severe asymmetric reduction in striatal FD uptake, with a rostrocaudal gradient in the putamen similar to that seen in adult-onset idiopathic parkinsonism. Extensive DNA analysis in this patient did not show mutations in the parkin gene.

Adolescent↗