Radiosurgical Thalamotomy for Essential Tremor: A Prospective Study with Blinded Assessment by a Movement Disorder Neurologist

PURPOSE/OBJECTIVE(S)

To prospectively evaluate the effectiveness and safety of radiosurgical thalamotomy in patients with Essential Tremor (ET).

MATERIALS/METHODS

Patients underwent stereotactic radiation VIM thalamotomy by a dedicated Cobalt 60 intracranial radiosurgery platform in a fixed headframe. 130 Gy was prescribed to the 100% isodose point with single 4mm collimator. Effectiveness was evaluated using validated tremor rating scale: upper limb CRST Part B ratings (CRST) in comparison to baseline. To be eligible minimal CRST score of 2 in writing or drawing was required. Writing and drawing score assessments were conducted by a single movement disorder neurologist in a blinded fashion. Mean writing and drawing scores were statistically compared with paired t-test.

RESULTS

A total of 213 cases (203 patients) were enrolled in the study, 7 cases (and individual patients) withdrew prior to treatment. The total number of thalamotomies performed was 206. Ten patients had right and left thalamotomies on study. Eleven patients underwent a contralateral thalamotomy but their initial thalamotomy was not a case in this study. 30 patients withdrew or were lost to follow-up, 2 patients were withdrawn due to not meeting medication criteria after treatment, 12 patients were withdrawn not meeting CRST rating criteria. Two patients were lost to follow-up immediately following the procedure (one of whom was a patient who underwent right and left staged procedures - no follow-up was obtained after the second procedure). 177 cases completed 6-month follow-up; 169 cases completed 1 year follow-up; 113 cases completed 2-year follow-up. For 189 total evaluable cases pre-treatment, drawing score mean was 2.86 +/- 0.84, pre-treatment writing score mean was 2.96 +/- 0.86. WRITING At one year: 143 cases (writing side targeted) mean writing score 1.28 +/-1.11 P<.01. 77% of cases improved by 1 point or greater. At two years: 102 cases 1.48+/-1.11, P<.01. 78% of cases improved by 1 point or greater. DRAWING At one year: 169 cases mean drawing score 1.42 +/-0.97, P<.01. 71% of cases improved by 1 point or greater. At two years: 113 cases mean drawing score 1.49+/-0.98, P<.01. 71% of cases improved by 1 point or greater. Cumulative side effects at 6 months and 1 year were seen in 17 of 175 of patients. 12 mild, 3 moderate and 2 severe. Mild side effects included numbness of the fingers, lip or hand and mild dysarthria. Severe side effects were 1 thalamic hemorrhage resulting in contralateral weakness. 1 patient developed foot drop and slurring of speech. Cumulative 2-year side effects were 15 mild, 3 moderate and 3 severe (1 additional thalamic hemorrhage).

CONCLUSION

Stereotactic radiosurgical thalamotomy provided a significant reduction in tremor at 1 and 2 years. The treatment is an effective noninvasive treatment option worthy of consideration in many patients. The treatment has a low but non-zero risk of significant SEs.

Cross-validation of the factor structure of the Toronto Alexithymia Scale

The Toronto Alexithymia Scale (TAS) is a self-report measure of the alexithymia construct. In previous studies with college students, the TAS demonstrated excellent psychometric properties including a 4-factor structure theoretically congruent with the alexithymia construct. The present study attempted to cross-validate the factor structure of the TAS with samples of normal adults, psychiatric outpatients and college students. Congruence coefficients comparing the similarity of the factor structures for these three samples indicated good congruence for all four factors. The results provide further support for the validity of both the TAS and the alexithymia construct. In addition, the results provide evidence of the applicability of the scale to normal adult and clinical samples.

Yes--occupational therapy can be dynamic in a chronic care setting

This article described the Occupational Therapy programs at Bloorview Children's Hospital. The Hospital itself and the structure within which Occupational Therapy operates are outlined. The numerous group programs are detailed, including objectives, target populations, activities and approach used.