Limits...
Quantitative analysis of tremors in welders.

Sanchez-Ramos J, Reimer D, Zesiewicz T, Sullivan K, Nausieda PA - Int J Environ Res Public Health (2011)

Bottom Line: Postural tremor intensity was increased in Welders and ET and was associated with visibly greater amplitude of tremor with arms extended.Mean center frequencies (Cf) of welders and patients with ET were significantly higher than the mean Cf of PD subjects.Although both the welders and the ET group exhibited a higher Cf with arms extended, welders could be distinguished from the ET subjects by a significantly lower Cf of the rest tremor than that measured in ET subjects.

View Article: PubMed Central - PubMed

Affiliation: College of Medicine, University of South Florida, Tampa, FL 33612, USA. jsramos@health.usf.edu

ABSTRACT

Background: Workers chronically exposed to manganese in welding fumes may develop an extra-pyramidal syndrome with postural and action tremors.

Objectives: To determine the utility of tremor analysis in distinguishing tremors among workers exposed to welding fumes, patients with Idiopathic Parkinson's Disease (IPD) and Essential Tremor (ET).

Methods: Retrospective study of recorded tremor in subjects from academic Movement Disorders Clinics and Welders. Quantitative tremor analysis was performed and associated with clinical status.

Results: Postural tremor intensity was increased in Welders and ET and was associated with visibly greater amplitude of tremor with arms extended. Mean center frequencies (Cf) of welders and patients with ET were significantly higher than the mean Cf of PD subjects. Although both the welders and the ET group exhibited a higher Cf with arms extended, welders could be distinguished from the ET subjects by a significantly lower Cf of the rest tremor than that measured in ET subjects.

Conclusions: In the context of an appropriate exposure history and neurological examination, tremor analysis may be useful in the diagnosis of manganese-related extra-pyramidal manifestations.

Show MeSH

Related in: MedlinePlus

Center Frequency (Cf) Analysis. The mean Cf for the tremors are significantly higher in Welders compared to PD under all conditions (right vs. left) and (resting vs. postural); paired two-tailed t-test (p = 0.009). The mean Cf of the postural tremors are higher in the welders compared patients with ET, but does not reach statistical significance. However, the Cf of the rest tremors in welders are significantly higher than in patients with ET. 2-way ANOVA of Cf of the ET group showed that rest vs. posture, but not right vs. left, contributed significantly to total variance (p = 0.009). The grey bands indicate the range of the mean Cf for each group of subjects and are intended to facilitate visual comparisons.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3108121&req=5

f2-ijerph-08-01478: Center Frequency (Cf) Analysis. The mean Cf for the tremors are significantly higher in Welders compared to PD under all conditions (right vs. left) and (resting vs. postural); paired two-tailed t-test (p = 0.009). The mean Cf of the postural tremors are higher in the welders compared patients with ET, but does not reach statistical significance. However, the Cf of the rest tremors in welders are significantly higher than in patients with ET. 2-way ANOVA of Cf of the ET group showed that rest vs. posture, but not right vs. left, contributed significantly to total variance (p = 0.009). The grey bands indicate the range of the mean Cf for each group of subjects and are intended to facilitate visual comparisons.

Mentions: The mean Center Frequency (Cf) of the postural tremors was significantly higher in welders and ET group compared to PD subjects (Figure 2). However, the Cf of the rest tremor in the ET group was significantly lower than the Cf of the rest tremor of the welders. The higher Cf in welders and ET compared to PD subjects was confirmed by analysis of energy distribution into two frequency bands, 3–6.5 Hz and 6.6 to 10 Hz. The resting tremor energy distribution in welders revealed a greater relative intensity at the higher frequency band (43% of total energy in both right and left hands) compared to the lower frequency band (27% on the left hand and 35% on the right). (Data not shown). In contrast, analysis of the PD subjects revealed that 53% of the total energy was distributed in the lower frequency band and 25% was in the higher frequency band (6.6 to 10 Hz). Analysis of the postural data revealed the same distribution pattern. In the ET group, a greater percentage of the energy of resting tremor was found in the lower frequency band (3 to 6.5 Hz), but with arms extended, the energy was equally distributed across both high and low frequency bands.


Quantitative analysis of tremors in welders.

Sanchez-Ramos J, Reimer D, Zesiewicz T, Sullivan K, Nausieda PA - Int J Environ Res Public Health (2011)

Center Frequency (Cf) Analysis. The mean Cf for the tremors are significantly higher in Welders compared to PD under all conditions (right vs. left) and (resting vs. postural); paired two-tailed t-test (p = 0.009). The mean Cf of the postural tremors are higher in the welders compared patients with ET, but does not reach statistical significance. However, the Cf of the rest tremors in welders are significantly higher than in patients with ET. 2-way ANOVA of Cf of the ET group showed that rest vs. posture, but not right vs. left, contributed significantly to total variance (p = 0.009). The grey bands indicate the range of the mean Cf for each group of subjects and are intended to facilitate visual comparisons.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3108121&req=5

f2-ijerph-08-01478: Center Frequency (Cf) Analysis. The mean Cf for the tremors are significantly higher in Welders compared to PD under all conditions (right vs. left) and (resting vs. postural); paired two-tailed t-test (p = 0.009). The mean Cf of the postural tremors are higher in the welders compared patients with ET, but does not reach statistical significance. However, the Cf of the rest tremors in welders are significantly higher than in patients with ET. 2-way ANOVA of Cf of the ET group showed that rest vs. posture, but not right vs. left, contributed significantly to total variance (p = 0.009). The grey bands indicate the range of the mean Cf for each group of subjects and are intended to facilitate visual comparisons.
Mentions: The mean Center Frequency (Cf) of the postural tremors was significantly higher in welders and ET group compared to PD subjects (Figure 2). However, the Cf of the rest tremor in the ET group was significantly lower than the Cf of the rest tremor of the welders. The higher Cf in welders and ET compared to PD subjects was confirmed by analysis of energy distribution into two frequency bands, 3–6.5 Hz and 6.6 to 10 Hz. The resting tremor energy distribution in welders revealed a greater relative intensity at the higher frequency band (43% of total energy in both right and left hands) compared to the lower frequency band (27% on the left hand and 35% on the right). (Data not shown). In contrast, analysis of the PD subjects revealed that 53% of the total energy was distributed in the lower frequency band and 25% was in the higher frequency band (6.6 to 10 Hz). Analysis of the postural data revealed the same distribution pattern. In the ET group, a greater percentage of the energy of resting tremor was found in the lower frequency band (3 to 6.5 Hz), but with arms extended, the energy was equally distributed across both high and low frequency bands.

Bottom Line: Postural tremor intensity was increased in Welders and ET and was associated with visibly greater amplitude of tremor with arms extended.Mean center frequencies (Cf) of welders and patients with ET were significantly higher than the mean Cf of PD subjects.Although both the welders and the ET group exhibited a higher Cf with arms extended, welders could be distinguished from the ET subjects by a significantly lower Cf of the rest tremor than that measured in ET subjects.

View Article: PubMed Central - PubMed

Affiliation: College of Medicine, University of South Florida, Tampa, FL 33612, USA. jsramos@health.usf.edu

ABSTRACT

Background: Workers chronically exposed to manganese in welding fumes may develop an extra-pyramidal syndrome with postural and action tremors.

Objectives: To determine the utility of tremor analysis in distinguishing tremors among workers exposed to welding fumes, patients with Idiopathic Parkinson's Disease (IPD) and Essential Tremor (ET).

Methods: Retrospective study of recorded tremor in subjects from academic Movement Disorders Clinics and Welders. Quantitative tremor analysis was performed and associated with clinical status.

Results: Postural tremor intensity was increased in Welders and ET and was associated with visibly greater amplitude of tremor with arms extended. Mean center frequencies (Cf) of welders and patients with ET were significantly higher than the mean Cf of PD subjects. Although both the welders and the ET group exhibited a higher Cf with arms extended, welders could be distinguished from the ET subjects by a significantly lower Cf of the rest tremor than that measured in ET subjects.

Conclusions: In the context of an appropriate exposure history and neurological examination, tremor analysis may be useful in the diagnosis of manganese-related extra-pyramidal manifestations.

Show MeSH
Related in: MedlinePlus