I

Tremor : an update

Prof. Kailash Bhatia

Institute of Neurology,

Queen Square,

London

MDJ- 2018

MDS Consensus Criteria for ET (Deuschl et al.1998) • Inclusion:

Bilateral, largely symmetrical postural or

kinetic tremor involving hands and forearms

that is visible and persistent

Additional (or isolated ! ) tremor of the head

may occur but without abnormal posturing

MDS Consensus Criteria for ET

• Exclusion criteria include:

Other signs, especially dystonia

Isolated position-specific

or task-specific tremor

ET has been considered as a pure or

monosymptomatic disorder but….

ET literature (and dystonia)

• Database of 350 pts with “ET”

• 47% of patients had associated dystonia

(Spasmodic Torticollis in 27%, Writers Cramp

in 14%, blepharospasm 7%, Spasmodic

Dysphonia 4%)

20% developed parkinsonism (after ET)

• ‘‘This analysis finds no support for differentiation of ET subtypes and

it suggests that ET, although heterogenous in its clinical presentation,

is a single disease entity.”

Lou & Jankovic,

Other features reported for ET

• Cerebellar dysfunction

• Cognitive changes- Duane et al , 2002, Higginson et al,

2008);- not controlled for depression, anxiety, co-

morbidities, medications, etc

• Olfaction: affected -Louis et al 2002 –however not found

in other studies (Shah et al); may be related to co-

morbidities or specific subgroup

• Hearing loss: Ondo et al, -but age dependent rather then

tremor severity dependent, age related?

Misdiagnosis of ET

What conditions are commonly mistaken

for ET and vice versa?

• Enhanced physiological tremor

• Tremulous dystonia or dystonic tremor

• PD, especially “BTP”

• Misdiagnosis rate of ET in 2 studies 37% (Jain et

al, 2007) and 50% (Schrag et al, 2000)

Dystonia in ET was reported in between 7- 47% in various studies

The definition of tremor has not changed

• An involuntary, rhythmic, oscillatory movement of a body part

• Problem: the only perfectly rhythmic tremor is primary orthostatic tremor

How rhythmic must an

oscillation be?

The concept of “isolated” and

“combined” tremor

Examples of Axis 1 classification

Essential tremor

Combined tremor syndromes

Isolated tremor syndromes

Dystonic tremor

Task-specific tremor

Primary orthostatic tremor

Rest tremor Bradykinesia

Rigidity

Tremor with ataxia

ET is a syndrome with multiple

etiologies.

• There is genetic heterogeneity.

• Many cases appear to be sporadic.

• It is an early phenotype of hereditary dystonia (eg, ANO3), hereditary ataxia (eg, SCA12), and Parkinson disease.

Louis. Arch Neurol 2009; 66: 1202-8

Deuschl et al. Mov Disord 2015; 30: 1327-34

Choudhury et al. Mov Disord Clin Pract 2018; 5: 39-46

Stamelou et al. Mov Disord 2014; 29: 928-934

ET plus “soft signs”

1. Rest tremor or questionable rest tremor

2. Impaired tandem gait

3. Questionable dystonic posturing of the hands, head, etc.

4. Memory impairment

5. Mild sensory neuropathy

6. Markedly asymmetric upper limb tremor

7. Jerky tremor

Strongly

discouraged.

Tremor Investigation Group (TRIG) 1990

Validity of subtle (soft)

signs of dystonia?

Courtesy

Roger Elble

ET plus is more common than

ET? Cohort of patients with lower limb tremor

Rajalingam et al. Parkinsonism Relat Disord 2018; 56: 109-110

A 69 year old man with a 10 year history of worsening tremor – possible

family history in mother late in her life – mild benefit with alcohol

Clinical example

Isolated

bilateral upper

extremity

tremor for 1

yr.

Strong Fam.

Hx

Action tremor

in the head,

voice and

upper limbs

Increased

tremor

Strained voice

Slight head tilt

Increased

tremor

Strained voice

Cervical

dystonia

ANO3

mutation

2 yr 3 yr 1 yr

Indeterminate

tremor ET ET plus

Antecedent

ET Antecedent

ET

ANO3

dystonia

Dystonic

tremor

syndrome

Stamelou et al. Mov Disord 2014; 29: 928-934.

Idiopathic

Familial

Idiopathic

Familial

Idiopathic

Familial

2 yr 3 yr 1 yr

Axis

1

Axis

2

Axis 1 classifications may change.

Clinical syndrome – Possible Essential tremor – but genetic diagnosis

DYT2 (HPCA gene mutations)

Axis 1 subtypes – more etiologic

specificity?

Data from one subtype may not be generalizable to other subtypes.

Management of Essential tremor

syndromes

Drugs :

• Propranolol

• Primidone

• Topirimate

Botulinum toxin injections:

Functional neurosurgery:

- VIM DBS

- Thalamic lesioning

- Focussed ultrasound

NEJM

2016

Orthostatic tremor- may be difficult to

visualise as very fast – but you could listen to

it!

Rubral tremor

70 year old with a 25 year history of postural tremor and more recent gait

disorder, cognitive problems, MRI shows some cerebellar atrophy

MDJ 2020 in press

Concluding remarks • New classification will help with :

• Effect of drugs such as propranolol, primidone

and others in different tremor syndromes

• And whether different targets should be

considered for DBS in ET syndrome versus DT

syndrome for example

• What about anticholinergics in ET plus with

dystonia?

• Outcomes and prognosis may differ