Glabellar reflex (Myerson's sign)!!!

"the preliminary note on a new cranial reflex"

British doctor Walker Overend (1858–1926)

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials

1/ Image
Glossary

Glabellar reflex
Habituation
Myerson’s sign
Primitive reflex

2/ Image
History

1896, Dr. Walker Overend
- first report

1901, Dr. Daniel J. McCarthy
- published a 2nd report without acknowledging Overend

1944, Dr. Abraham Myerson
- observed, mainly, in PD

1954, Dr. Doshay
- called Myerson’s sign

3/ Image
Pathophysiology

poorly understood, probably partially related to the blink reflex

Afferent: V CN (supraorbital nerve)
Efferent: VII CN (orbicularis oculi muscle)

moderated by
- cortical areas, especially the frontal lobe
- subcortical areas, especially basal ganglia

4/ Image
Clinical use

a)may present healthy pts & infants

b)inc prevalence w/ age

c) disease severity

d)differentiate PD from ET (Nuuttila 2021)
- sensitivity 78.3% & specificity 36.2%

e)reverse after levodopa in PD (Klawans 1969)
- 50%
- no reverse: dementia & severe PD

5/
Definition

“unable to resist blinking when tapped repetitively on the glabella”

How many times to tap till be abnormal?

The magic number is “five” based in pediatric studies
(Zametkin et al 1979)

6/
Glabellar reflex – features

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

7/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Neurology Made Interesting

8/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Neurology Made Interesting

9/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Dr. Sourya Acharya

10/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

youtube.com/shorts/GRqAgon… via: Neurozone videos

11/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Osama SM Amin

12/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Neurolibrary

13/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

youtube.com/shorts/UFokLDz… via: Dr Hamza Khan Malezai

14/
Glabellar reflex

“unable to resist blinking when tapped repetitively on the glabella”

- primitive reflex
- aka Myerson's sign
- PD and dementia, severity?

via: Dr. Ravi Ranjan Kindo

15/
Other frontal release signs

Palmar grasp, palmomental, rooting & sucking, snout, corneomandibular reflex, and head retraction reflex


16/

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More from @theneurolander

Dec 1
Milkmaid’s grip!!!

“motor impersistence of the hand”

Philippus Aureolus Theophrastus Paracelsus Bombastus von Hohenheim (1493–1541)
(Paracelsus)
first coined the term Chorea Sancti Viti

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1/ Image
Pathophysiology

“combination of chorea & motor impersistence”

Motor impersistence
- inability to maintain tetanic muscle contraction
- positioning & compensatory repositioning
- independent of chorea
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- frontal lobe

2/ Image
Examples of motor impersistence

- Milkmaid’s grip
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Wing-beating tremor!!!

“pseudosclerotic, parkinsonism, and dystonic/choreic forms of Wilson’s disease”

American-born British neurologist Samuel Alexander Kinnier Wilson (1878–1937)

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1/
Pathophysiology

“lesion in the dentatorubrothalamic pathway”

- cerebellar outflow pathway

Complex phenomenology
- dystonic, myoclonic, rhythmic tremor?


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Definition

“low-frequency, high-amplitude, posture-induced proximal arm tremor, elicited by sustained abduction of the arms, with flexed elbows and palms facing downward”

- postural tremor
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Nystagmus series – Part VII
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“Maddox rod, double prism Maddox, red glass Maddox, Maddox cross, and Maddox wing”

British ophthalmologist Ernest Edmund Maddox (1863–1933)
(first report)

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials

1/ Image
Definition

“one half-cycle of elevation&intorsion of one eye
and
synchronous depression&extorsion of the other eye.
Next half-cycle,
vertical&torsional components are reversed”

- waveform: pendular (seesaw) & jerk (hemi-seesaw)
- hemi-seesaw: only one half-cycle

2/ Image
Pathophysiology

Jerk (hemi-seesaw)
- lesion in the interstitial nucleus of Cajal

Pendular (seesaw)
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- calibration lesion

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Nov 25
Head retraction reflex!!!

“the great neurologist and neurosurgeon from Breslau (Wrocław)”

German neurologist and neurosurgeon Otfrid Foerster (1873–1941)

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials

1/ Image
History

Head retraction reflex is a “triphasic cutaneomuscular reflex” related to the trigeminal system with some pyramidal control.

2/ Image
Features

“reflex hammer tap below nose with head bent forward cause backward jerk of the head”

- considered a frontal release sign
- hyperreflexia
- triphasic cutaneomuscular reflex

3/ Image
Read 13 tweets
Nov 23
Corneomandibular reflex!!!

“there is hardly a more valuable test than this to uncover a supranuclear lesion of the trigeminal nerve”

Russian neurologist Robert Wartenberg (1887–1956)

#MedTwitter #neurotwitter #EndNeurophobia #tweetorials

1/
History

1902 by German doctor Von Sölder
- first description, normal patients

1918 by German neurologist Ernst Trömner
- rediscovered the reflex

1948 by Russian neurologist Robert Wartenberg
- complete description
- ‘jaw wincking phenomenon’

2/
Pathophysiology

Mesencephalic trigeminal nucleus
- there is an inhibitory interneuron ipsilateral motor nucleus of V CN

Lesions in cortico-pontine boundaries lesions
- inhibitory influence disappear
- massive activation of trigeminal motor neuron

doi.org/10.4103%2F0976…

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Read 9 tweets
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Movement disorders specialists, I would appreciate your opinion.
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I found the movements too quick and too high amplitude to be polyminimyoclonus.
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@AlbertoEspay @SanjayP30043502 @AbhiLenka11 @JackyGanguly
MYBPC1 mutation are associated with myogenic tremor and mild myopathy

doi.org/10.1002/ana.25…
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doi.org/10.1002/ana.25…
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