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Biomedical subjects

C M Tanner

Publications and source records attributed to C M Tanner.

At least 19 recordsLinked to original sources
PubMed2001

An impairment in sniffing contributes to the olfactory impairment in Parkinson's disease.

Although the presence of an olfactory impairment in Parkinson's disease (PD) has been recognized for 25 years, its cause remains unclear. Here we suggest a contributing factor to this impairment, namely, that PD impairs active sniffing of odorants. We tested 10 men and 10 women with clinically typical PD, and 20 age- and gender-matched healthy controls, in four olfactory tasks: (i) the University of Pennsylvania smell identification test; (ii and iii) detection threshold tests for the odorants vanillin and propionic acid; and (iv) a two-alternative forced-choice detection paradigm during which sniff parameters (airflow peak rate, mean rate, volume, and duration) were recorded with a pneomatotachograph-coupled spirometer. An additional experiment tested the effect of intentionally increasing sniff vigor on olfactory performance in 20 additional patients. PD patients were significantly impaired in olfactory identification (P < 0.0001) and detection (P < 0.007). As predicted, PD patients were also significantly impaired at sniffing, demonstrating significantly reduced sniff airflow rate (P < 0.01) and volume (P < 0.002). Furthermore, a patient's ability to sniff predicted his or her performance on olfactory tasks, i.e., the more poorly patients sniffed, the worse their performance on olfaction tests (P < 0.009). Finally, increasing sniff vigor improved olfactory performance in those patients whose baseline performance had been poorest (P < 0.05). These findings implicate a sniffing impairment as a component of the olfactory impairment in PD and further depict sniffing as an important component of human olfaction.

Adult↗
PubMed2000

Provocative discography in patients after limited lumbar discectomy: A controlled, randomized study of pain response in symptomatic and asymptomatic subjects.

STUDY DESIGN: This was a prospective observational study of patients with low back pain and those without after laminotomy and discectomy. OBJECTIVES: To determine, using a strict experimental design, the relative pain intensity response to provocative discography in symptomatic and asymptomatic subjects after lumbar discectomy for intervertebral disc herniation. BACKGROUND: Provocative discography frequently is used to evaluate persistent or recurrent low back pain syndromes in patients who have undergone posterior discectomy. The validity of interpreting painful injections during this procedure has not been critically assessed. The prevalence of significantly painful disc injections in a group with good outcomes after surgery is not known. Knowing the rates of significantly painful injections in asymptomatic patients after lumbar discectomy may clarify the meaning of painful injections in symptomatic patients. METHODS: From a cohort of 240 patients who had undergone single-level limited discectomy for sciatica, 20 asymptomatic volunteers were recruited for experimental three-level lumbar discography. Inclusion criteria required nearly perfect scores on standardized back pain rating instruments, no other spinal pathology, and normal psychometric screening. A control group of 27 symptomatic patients, after single-level discectomy with intractable low back pain syndrome, and without other spinal pathology, underwent discography. Seven patients in the control group had normal psychometric tests. Experienced raters who were blinded to control versus experimental status of the subjects scored the magnetic resonance imaging, discogram, psychometric tests, and discography videotapes of the subjects' pain behavior. RESULTS: There were 8 of 20 (40%) positive injections of discs that had previous surgery in the asymptomatic group and 17 of 27 (63%) positive injections in the symptomatic group. Specifically with regard to the symptomatic group, there were 3 of 7 (43%) positive injections (all concordant) in patients with normal psychometric scores, as compared with 14 of 20 (70%) positive injections (12 concordant) in patients with abnormal psychometric scores. Injections of discs that had previous surgery resulted in a mean pain score of 2.1 of 5 in the asymptomatic group, 2.1 in the symptomatic group with normal psychometric scores, and 3.4 in the symptomatic group with abnormal psychometric scores. Of the discs not treated with surgery, 2 were positive in the asymptomatic group (10%), 3 in 2 symptomatic subjects with normal psychological testing (29), and 18 in 13 symptomatic subjects with abnormal psychometric testing (76%). CONCLUSIONS: A high percentage of asymptomatic patients with normal psychometric testing who previously have undergone lumbar discectomy will have significant pain on injection of their discs that had previous surgery (40%). This is not significantly different from the experience of symptomatic patients with normal psychometric testing undergoing discography on discs that had previous surgery. Patients with abnormal psychological profiles have significantly higher rates of positive disc injections than either asymptomatic volunteers or symptomatic subjects with normal psychological screening.

Adult↗
PubMed2000

Can discography cause long-term back symptoms in previously asymptomatic subjects?

STUDY DESIGN: A prospective controlled study of patients without low back pain observed after experimental lumbar discography. OBJECTIVES: To determine whether discography may cause long-term low back symptoms in selected patients. BACKGROUND: Lumbar discography is generally considered safe, although controversial, with few complications. There is little information on long-term follow-up of asymptomatic patients after experimental discography. METHODS: Twenty-six patients without pre-existing low back pain were observed for 1 year after lumbar discography to determine the effects of lumbar discography in three experimental groups: 10 patients who had remote cervical spine surgery with excellent results (pain-free group); 10 patients who had the same surgery with poor results (chronic pain group); and 6 patients who had primary somatization disorders. Two control groups were also observed: a group of patients with somatization disorder who were similarly evaluated but without discography, a group of patients with low back pain observed for 1 year after discography without surgery. RESULTS: In the three experimental groups (no back pain before discography) no subject with normal psychometric testing had persistent pain after discography (0/11), whereas 6 (40%) of 15 with abnormal psychometric test results reported significant new low back pain. None of the pain-free group (0/10), 20% of the chronic neck pain group (2/10), and 66% of the somatization group (4/6) continued to have significant back pain 1 year after injection. Psychological testing and occupational disability strongly predicted continued pain after discography. The control groups had no significant change in low back symptomatology during the year of observation. CONCLUSION: Discography in a subject group without low back pain but with significant emotional and chronic pain problems may result in reports of significant back pain for at least 1 year after injection. Subjects with normal psychometric test results had no reports of significant long-term back pain after discography.

Adult↗
PubMed2000

The rates of false-positive lumbar discography in select patients without low back symptoms.

STUDY DESIGN: Experimental disc injections in subjects with no history of low back symptoms. OBJECTIVE: To determine in an experimental setting the relative pain response and pain-related behavior in selected subjects without a history of low back pain undergoing lumbar discography. This study aimed to select a study population that more closely represented patients undergoing discography in clinical practice. SUMMARY OF BACKGROUND DATA: Previous work has shown that in young, healthy men with little degenerative disc disease and no history of low back problems, discographic injections usually did not cause significant pain. This group differed from the patients who usually undergo discographic evaluation in clinical practice. Most clinical patients are older, have significant degenerative disc disease, have behavioral changes associated with chronic pain, and often have confounding psychosocial troubles. The authors undertook to study discography in subjects without low back pain but with clinical profiles similar to patients undergoing discography in clinical practice. METHODS: Twenty-six individuals, mean age 43 years, with no history of low back pain had lumber discography according to the strict protocol of Walsh et al. Of these, 10 were pain-free; 10 had chronic neck and arm pain, but no low back symptoms; and 6 had primary somatization disorders without low back symptoms.- RESULTS: Significant positive pain response and pain-related behavior with discography were found in 10% of the pain-free group, in 40% of the chronic cervical pain group, and in 83% of the somatization disorder group completing the injections. Twenty-four subjects had negative control discs. Discs with annular disruption were more likely to be painful on injection, particularly in those individuals with ongoing compensation issues, chronic pain, or abnormal psychological testing.- CONCLUSION: If strict criteria are applied, the rate of false-positive discography may be low in subjects with normal psychometric profiles and without chronic pain. Significantly painful injections were very common in subjects with annular disruption and chronic pain or abnormal psychometric testing.

Adult↗
PubMed2000

Epidemiology of Parkinson's disease and akinetic syndromes.

New reports of the incidence, prevalence and mortality of Parkinson's disease and parkinsonism are reviewed. Evidence for occupational and lifestyle risk factors and protective factors is updated. Recent genetic epidemiology studies of parkinsonism in twins and families, and studies that investigated imaging and physiologic markers of dopaminergic function in members without parkinsonism are presented.

Genetic Predisposition to Disease↗
PubMed1999

False-positive findings on lumbar discography. Reliability of subjective concordance assessment during provocative disc injection.

STUDY DESIGN: Experimental disc injections in subjects with no history of low back symptoms. OBJECTIVE: To determine in an experimental model the reliability of patients' subjective interpretation of pain concordancy during provocative disc injection. BACKGROUND: Discography in the evaluation of low back pain relies on a patient's subjective assessment of pain magnitude and quality during disc injection. Reproduction of significant pain on disc injection, which is similar to patients' usual pain, is believed to prove that the disc injected is the source of the patient's low back pain. In the current study, this hypothesis was tested in a controlled setting on patients with known nonspinal pain in a common referral area of discogenic pain. METHODS: Patients with no history of low back pain were recruited to participate in a study of discography. Patients scheduled to undergo posterior iliac crest bone graft harvesting for nonthoracolumbar procedures were evaluated with lumbar radiography, magnetic resonance imaging, and psychometric testing. Two to 4 months after bone graft harvesting, patients underwent lumbar discography by strict blinded protocol. Patients were asked to compare the sensations elicited at discography to their usual back/buttock pain since bone graft harvesting. Pain was rated as 0-5 on a pain thermometer and concordancy was rated as none, dissimilar, similar, or exact. RESULTS: Eight subjects completed the study, and 24 discs were injected. Of the 14 disc injections causing some pain response, 5 were believed to be "different" (nonconcordant) pains (35.7%); 7 were "similar" (50.0%), and 2 were "exact" pain reproductions (14.3%). The presence of anular disruption predicted concordant pain reproduction (P < 0.05). Of 10 discs with anular tears, injection of 5 elicited pain that was similar to or an exact reproduction of pain at the iliac crest bone graft harvest sites. By the usual criteria for positive discography, 4 of the 8 patients (50%) would have been classified as positive. In these patients, the pain on a single disc injection was very painful, and the pain quality was noted to be exact or similar to the usual discomfort. All subjects had a negative control disc. CONCLUSIONS: The findings of this study demonstrate that patients with no history of low back pain who had undergone posterior iliac bone graft harvesting for nonlumbar procedures often experienced a concordant painful sensation on lumbar discography with their usual gluteal area pain. Thus, the ability of a patient to separate spinal from nonspinal sources of pain on discography is questioned, and a response of concordant pain on discography may be less meaningful than often assumed.

Adult↗
PubMed1999

Parkinson disease in twins: an etiologic study.

CONTEXT: The cause of Parkinson disease (PD) is unknown. Genetic linkages have been identified in families with PD, but whether most PD is inherited has not been determined. OBJECTIVE: To assess genetic inheritance of PD by studying monozygotic (MZ) and dizygotic (DZ) twin pairs. DESIGN: Twin study comparing concordance rates of PD in MZ and DZ twin pairs. SETTING AND PARTICIPANTS: A total of 19842 white male twins enrolled in the National Academy of Sciences/National Research Council World War II Veteran Twins Registry were screened for PD and standard diagnostic criteria for PD were applied. Zygosity was determined by polymerase chain reaction or questionnaire. MAIN OUTCOME MEASURE: Parkinson disease concordance in twin pairs, stratified by zygosity and age at diagnosis. RESULTS: Of 268 twins with suspected parkinsonism and 250 presumed unaffected twin brothers, 193 twins with PD were identified (concordance-adjusted prevalence, 8.67/1000). In 71 MZ and 90 DZ pairs with complete diagnoses, pairwise concordance was similar (0.129 overall, 0.155 MZ, 0.111 DZ; relative risk, 1.39; 95% confidence interval, 0.63-3.1). In 16 pairs with diagnosis at or before age 50 years in at least 1 twin, MZ concordance was 1.0 (4 pairs), and DZ was 0.167 (relative risk, 6.0; 95% confidence interval, 1.69-21.26). CONCLUSIONS: The similarity in concordance overall indicates that genetic factors do not play a major role in causing typical PD. No genetic component is evident when the disease begins after age 50 years. However, genetic factors appear to be important when disease begins at or before age 50 years.

Adult↗
PubMed1998

Failure to find the alpha-synuclein gene missense mutation (G209A) in 100 patients with younger onset Parkinson's disease.

The missense G209A mutation at exon 4 of the alpha-synuclein gene was recently found to be responsible for familial Parkinson's disease (PD) in a large kindred of Italian descent. We studied 100 typical PD patients with onset before age 51, both with and without a family history of PD. We did not find this alpha-synuclein missense mutation in any patient, but it was present in a symptomatic member of the Contursi family.

Adult↗
PubMed1998

Absence of mutations in the coding region of the alpha-synuclein gene in pathologically proven Parkinson's disease.

A missense mutation of the alpha-synuclein gene has been associated with parkinsonism in a large Italian kindred. Recently, alpha-synuclein was also identified in Lewy bodies. Using reverse transcribed-polymerase chain reaction (RT-PCR) technique, we sequenced the entire coding region of the alpha-synuclein gene using brain tissue from 24 pathologically proven Parkinson's disease cases. No mutations were found in any of the patients, suggesting that a mutation at the coding region of the alpha-synuclein gene is unlikely to be responsible for nigrostriatal degeneration in typical sporadic Parkinson's disease.

Adult↗
PubMed1998

Early dopaminergic drug-induced hallucinations in parkinsonian patients.

OBJECTIVE: To characterize patients who develop hallucinations early in the course of dopaminergic therapy for Parkinson's disease (PD) and contrast them with patients developing hallucinations after chronic drug treatment. METHODS: Parkinsonian patients who met diagnostic criteria for PD, experienced hallucinations, had a detailed hallucination interview at the onset time of their first hallucination, and had a 5-year clinical follow-up or an autopsy in those 5 years were identified and divided into two groups for comparison: 12 patients who developed early hallucinations within 3 months of starting levodopa therapy and 58 PD patients who developed hallucinations after 1 year of dopaminergic therapy. We contrasted the quality, content, diurnal nature, and emotional elements of the hallucinations, as well as the 5-year follow-up data on diagnosis, disease course, community home or nursing home outcome, and mortality. RESULTS: Both groups experienced a predominance of visual hallucinations, visions of people and animals, and vivid colors and definition. Features distinctive to the early onset hallucinating patients included visions that persisted in daytime as well as nighttime, frightening content with paranoia, and accompanying nonvisual hallucinations, either auditory, olfactory, tactile, or combinations thereof. At the 5-year follow-up, none of the early onset hallucinators had PD as their sole disorder. Four of the 12 had an underlying psychiatric illness that included hallucinations or psychosis preceding their parkinsonism by several years. In the other eight patients at the 5-year follow-up, their parkinsonism evolved to include additional signs that were no longer consistent with PD. The primary diagnoses were diffuse Lewy body disease and Alzheimer's disease (AD) with extrapyramidal signs. Patients with early drug-induced hallucinations had significantly greater placement to nursing homes and greater mortality. CONCLUSIONS: Early onset drug-related hallucinations are not typical of PD. Their presence should signal an investigation of two alternative diagnoses, either a comorbid psychotic illness (often unrevealed by the patient initially) or an evolving parkinsonism-plus syndrome.

Aged↗
PubMed1997

Epidemiology of Tourette syndrome.

The epidemiology of Tourette syndrome is difficult to characterize because there is no definitive diagnosis. Symptom intensity and frequency decrease with age and in social situations, and affected individuals are often unaware of their tics. This chapter reviews and summarizes current data on the prevalence, distribution, and risk factors for Tourette syndrome.

Humans↗
PubMed1996

Early intervention in Parkinson's disease: epidemiologic considerations.

This article examines the different forms of movement disorders, with a particular focus on Parkinson's disease. Screening strategies for Parkinson's disease are reviewed; these include biochemical measures, physiologic testing, positron-emission tomography, and early identification of symptoms by interview. Problems posed by the epidemiologic investigation of Parkinson's disease are considered.

Epidemiologic Methods↗
PubMed1996

CYP2D6 allelic frequencies in young-onset Parkinson's disease.

Parkinson's disease (PD) is thought to develop as a result of interactions between genetic susceptibility factors and environmental exposures. One candidate gene is CYP2D6, which codes for the debrisoquine 4-hydroxylase cytochrome P450. Impairment of debrisoquine 4-hydroxylase activity has been associated with an increased risk of PD in patients with younger age at disease onset. Genotyping studies in patients with an older age at onset have reported modest increases in risk associated with the CYP2D6 B and A alleles; however, the risk for young-onset PD has not been adequately evaluated. We designed a case-control study to investigate the role of nonfunctional CYP2D6 allelic risk factors for young-onset PD in a sizable patient population and compared the distributions of CYP2D6 genotypes between young-onset ( < or = 51 years) PD patients (n = 108) and controls (n = 236). In contrast with the results from genotyping studies conducted among patients with an older age at onset, there were no significant differences in CYP2D6 allelic frequencies between young-onset PD cases and controls. The frequency of the B allele was slightly lower in the young-onset PD cases than in the controls (0.14 versus 0.20) (X2 = 2.66, p = 0.10). The presence of one or more B alleles was not associated with an increased risk of young-onset PD (odds ratio 0.58; 95% CI 0.33 to 1.00), nor was the presence of one or more nonfunctional alleles (i.e., A, B, D, and D2) (odds ratio 0.68; 95% CI 0.41 to 1.13). This study suggests that the young-onset PD population may differ from the older-onset population with respect to risk factors.

Age of Onset↗