The objective of the study was to compare ET with tremor dominant PD in domains of cognition, associated depression and quality of life.

People more than 18years age who met Criteria for ET and Tremor Dominant PD were studied in   one-year period. Essential Tremor Rating  Scale (TETRAS), UPDRS-III, Hamilton Depression Rating Scale, Montreal cognitive assessment (MOCA), QUEST (Quality of life in Essential Tremor Questionnaire) were assessed.

71 cases (30 ET and 41 tremor dominant PD) were studied. Mean duration of symptoms was 10 years for ET and 4 years for PD-TD respectively with significant p-value. ET and PD-TD had both showed mild depression on HDRS. ET had higher mean MOCA suggesting better cognition in ET than PD-TD. QUEST shown no significant difference in any variables except finance where PD patients had significant issues. QOL rating showed no difference suggesting both had equal QOL impairment contrary to the popular belief that ET has better QOL than PD-TD. There was negative correlation between TETRAS and QUEST. UPDRS-III with MOCA and QUEST showed negative correlation suggesting as disease worsens QOL worsens in both groups. But, patients with  ET had better scores on MOCA when  compared to PD.

Conclusion: ET and Tremor Dominant PD show similar changes in QOL and HDRS suggesting ET was more  than just a benign, mono-symptomatic disease. ET patients had better scores than PD-TD on MOCA suggesting minor abnormalities in cognition in PD-TD.