Essential tremor 10, 20, 30, 40: clinical snapshots of the disease by decade of duration.

BACKGROUND AND PURPOSE: Essential tremor (ET) is a chronic, progressive neurological disorder in which disease burden may slowly accrue. There are few long-term studies, and the clinical and functional status of patients, with each decade of disease duration, has not been documented in detail. We used cross-sectional data on 335 patients with ET (disease duration 1-81 years) to produce clinical snapshots of the disease at each 10-year milestone (i.e. < 10, 10-19, 20-29, 30-39, ≥ 40 years). We hope these data will be of value in clinical-prognostic settings both to patients and their treating physicians. METHODS: In this cross-sectional, clinical-epidemiological study at Columbia-University Medical Center, each patient underwent a single evaluation, including self-reported measures of tremor-related disability, performance-based measures of function, and neurologist-assessments of tremor type, location and severity. RESULTS: A variety of metrics of tremor severity increased across the 10-year time intervals. By ≥ 40 years duration, one-third of patients had tremor in at least two cranial locations (neck, voice, jaw), and the proportion with high-amplitude tremor reached 20.3% (while drawing spirals), 33.8% (spilling while drinking) and 60.8% (spilling while using a spoon). Yet even in the longest tremor duration group, very few (< 10%) were incapacitated (i.e. completely unable to perform the above-mentioned tasks), and one-third continued to exhibit no cranial tremor. CONCLUSIONS: These data paint a picture of progressive decade-by-decade decline in ET. Yet patients with long disease duration did not relentlessly converge at the same end-stage of severe, functionally incapacitating, diffuse tremor. In this respect, long-duration ET patients presented a heterogeneous picture.

Depressive traits in essential tremor: impact on disability, quality of life, and medication adherence.

BACKGROUND: There is growing study of the psychiatric features of essential tremor. Depressive symptoms occur in a considerable number of patients. Yet their impact, as a primary factor, has received almost no attention. We assessed whether, independent of tremor severity, patients with more depressive symptoms have more perceived tremor-related disability, lower tremor-related quality of life, and poorer compliance with tremor medication. METHODS: On the basis of their Center for Epidemiological Studies Depression Scale score, we stratified 70 essential tremor patients into three groups: 41 with minimal depressive symptoms, 24 with moderate depressive symptoms, and five with severe depressive symptoms. Importantly, the three groups had similar tremor severity on neurological examination. We assessed self-reported tremor-related disability, tremor-related quality of life (Quality of Life in Essential Tremor) (QUEST) score, and medication compliance. RESULTS: Cases with minimal depressive symptoms had the lowest QUEST scores (i.e., highest quality of life), cases with moderate depressive symptoms had intermediate scores, and those with severe depressive symptoms had the highest QUEST scores (i.e., lowest quality of life) (P < 0.001). Depressive symptoms were a stronger predictor of tremor-related quality of life than was the main motor feature of essential tremor (ET) itself (tremor). Self-reported medication compliance was lowest in cases with severe depressive symptoms and highest in cases with minimal depressive symptoms. CONCLUSIONS: The physical disability caused by the tremor of ET has traditionally been regarded as the most important feature of the disease that causes distress, and it has received the most attention in the management of patients with this disease. Our data indicate that this may not be the case.

Color vision: a study of essential tremor cases versus normal controls.

BACKGROUND AND PURPOSE: Patients with essential tremor (ET) and Parkinson's disease (PD) may exhibit overlapping clinical features. Also, a growing number of non-motor features are being documented in ET. Color vision abnormalities, although well known to occur in PD, have not been studied extensively in ET. We assessed color vision in ET cases and controls. We furthermore assessed subgroups of ET cases with clinical features that might link them to PD (i.e., ET cases with a family history of PD, and ET cases with rest tremor) to determine whether these cases had greater color vision abnormalities than ET cases without those features. METHODS: Participants were enrolled in a case-control study at Columbia University Medical Center. Color discrimination testing was performed using the Farnsworth-Munsell 100 Hue test. The total error score (TES) for the hue test was determined. RESULTS: The TES was similar in 55 ET cases and 55 controls (144.6 ± 91.8 vs. 145.6 ± 96.6, P = 0.96). ET cases with rest tremor (n = 8) were similar to ET cases without rest tremor (n = 47) with respect to the TES (117.0 ± 73.4 vs. 149.3 ± 94.4, P = 0.36), as were ET cases with a family history of PD (n = 9) versus without (n = 46) (144.4 ± 57.0 vs. 144.6 ± 97.6, P = 0.996). CONCLUSIONS: Although a number of links exist between ET and PD, and non-motor features have been described in both, a color vision abnormality does not seem to be a feature of ET.