4
Differential Diagnosis
ET Plus
• There are several soft signs that can be seen with ET that are now termed
"ET Plus."
▶ For instance, many people with very long-standing ET may develop gait ataxia and
rest tremor.
▶ Dystonic features (subtle posturing of the hands or head) can be seen in some
people with ET.
▶ At this time, it is not known whether these neurological disorders are distinctly
different from classical ET.
Table 2. Comparing Signs/Symptoms of ET and PD
Essential Tremor Parkinsonian Tremor
Most commonly affects upper limbs, head,
voice
Most commonly affects upper limbs and
less commonly lower limbs and jaw. Voice
and head almost never affected
Typically bilateral Begins unilateral and generally progresses
to bilateral
Tremor primarily postural and kinetic
(action tremor), rarely at rest
Tremor primarily at rest may have postural
tremor (re-emergent), rarely kinetic
4–12 Hz tremor 3–6 Hz tremor
Tremor is primary symptom – slowness,
stiffness, walking and balance problems are
not commonly seen.
Slow movements (bradykinesia, rigidity
(stiffness), and problems with walking or
balance
Family history of tremor reported in the
majority of patients
Rarely a family history (<20%)
Onset most common aer 40 but can
occur at any time in the lifespan
Average onset around 60 years, can be any
time throughout adulthood
Alcohol oen improves tremor Alcohol does not improve tremor
Worsens with stress/emotion Worsens with stress/emotion
About 8× more common than PD Much less common than ET
DaTscan normal DaTscan abnormal
Handwriting oen large and tremulous Handwriting oen micrographic and not
tremulous
