The Essential Tremor Rating Assessment Scale (TETRAS)
A two-subscale tremor rating instrument developed by the Tremor Research Group.
By Claire White
- ADL subscale: self-reported, 12 items, 0 to 48.
- Performance subscale: clinician-administered, 9 items, 0 to 36. Tasks include upper limb tremor, head tremor, voice tremor, and gait.
- Lower scores indicate less tremor.
- Used in essential tremor and Parkinson's tremor research.
What it measures
The TETRAS ADL subscale asks the patient about how tremor affects daily tasks such as writing, drinking, eating, and dressing. The Performance subscale has the clinician rate tremor during standardised tasks: upper limb posture and action tremor (arms outstretched and wing position), head tremor, voice, and gait. Each is rated 0 to 4 on severity.
What the result tells you
Lower scores on both subscales indicate less tremor. The subscales can be used separately or together. The Performance subscale is the standard research outcome for trials of tremor-suppressing interventions. The ADL subscale captures functional impact from the patient’s perspective.
Used for
Evidence, psychometrics and provenance
Psychometrics
Reliability on a 0 to 1 scale. Higher is better.
References
This assessment uses a validated instrument and is reference information, not a diagnosis.