SEIZURE SEMIOLOGY TWEETORIAL
#Epilepsy #Neurotwitter #Seizure #Semiology

🧵1/ What is a visual aura?
Visual auras consist of brief, stereotypical, visual hallucinations of static, flashing or moving lights in different shapes and colors, complex hallucinations and illusions. ImageImage
2/ Visual auras can be classified into many types- simple visual hallucinations, complex visual hallucinations, visual illusions and ictal amaurosis. #Seizure #Semiology #Neurotwitter ImageImage
3/ Simple visual hallucinations are typically described as flashing lights of different shapes-circles, stars, halo, lines, spots etc. These may or may not be colored. They may or may not move. These always lateralize to the contralateral hemisphere. #Neurotwitter ImageImage
4/ Simple visual hallucinations have a very high localizing value to the occipital lobe. In Penfield & Kristiansen, 11 patients had visual sensation as the initial seizure manifestation. In all patients, the epileptogenic lesion was in the occipital lobe. ImageImage
5/ The symptomatogenic zone of simple visual hallucinations includes primary and secondary visual areas in the occipital lobe- BA 17, 18 and 19. Functional areas of the visual cortex are classified as V1-V5 and don't necessarily agree with Brodmann areas.
6/ It is generally agreed that static simple visual hallucinations originate from V1 (which is mostly located on the mesial occipital surface; pericalcarine cortex; BA 17) whereas moving simple hallucinations localize to V2 and V3. ImageImageImageImage
7/ First reports of visual hallucinations secondary to cortical stimulation came from Krause in 1924 and Foerster in 1936. This was followed by the pioneering work of W. Penfield & H. Jasper. They only found simple visual auras in occipital lobe stimulations. Image
8/ Complex visual hallucinations consist of formed images, which may appear as animals, people or scenes. These are believed to reflect activation of a wide visual association cortex. They can be elicited from mesial parietal, lateral and basal occipitotemporal regions. ImageImage
9/ Visual illusionary auras (micropsia, macropsia, metamorphopsia, teleopsia, pelopsia, palinopsia) reflect misperceptions of real external visual stimuli. They are often clubbed under 'psychic auras' & don't have a discrete localization, but are seen with temporal lobe seizures. Stimulation at points anter...Image
10/ Ictal amaurosis is a negative manifestation of a seizure discharge affecting the visual cortex. The temporary blindness can be bilateral or restricted to one hemifield or one quadrant.
11/ The first case of occipital lobe epilepsy with visual aura was reported by Gowers in 1879. His patient described a brilliant image of a "gold serpent" with his seizures. This was further elaborated by Gordon Holmes and Penfield with his colleagues.
12/ Multiple studies of patients with occipital lobe epilepsies has shown that majority of the patients have a visual hallucination as the initial manifestation of the seizure. ImageImage
13/ In a series of 42 patients with refractory occipital lobe epilepsy from @TheNeuro_MNI between 1930 and 1991, 73% had visual auras, majority of which were simple hallucinations, whereas 12 patients had ictal blindness. Image
14/ Conclusion- The simple visual hallucinations have a very high localizing value to the occipital lobe. When these are lateralized, the seizure onset zone is contralateral. Identification of visual auras can significantly aid in localizing the EZ to the occipital lobe.

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Case Western Reserve Univ/UH Epilepsy Program

Case Western Reserve Univ/UH Epilepsy Program Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @CwruEpilepsy

May 21
SEIZURE SEMIOLOGY #TWEETORIAL
#Epilepsy #Seizure #NeuroX

🧵1/ What is abdominal (or epigastric) aura?
Abdominal aura is characterized by an uncomfortable sensation in the abdominal region w/wo nausea and w/wo a characteristic 'rising' quality. Image
2/ In majority of cases, this feeling is localized to the epigastric area, hence the other term 'epigastric aura'. #AurasInEpilepsy #SeizureSemiology
Image
Image
3/ The subjective descriptions of the abdominal aura are quite variable such as 'pain', 'nausea', 'sinking feeling', 'butterflies', 'fluttering', 'fullness', etc. Hence, this aura is mainly defined by the location of the body region affected, rather than type of sensation.
Image
Image
Read 19 tweets
Jan 22
SEIZURE SEMIOLOGY TWEETORIAL (UPDATE)
#Epilepsy #NeuroX #Seizure

What more have we learnt about clonic seizures?
neurology.org/doi/full/10.12…

Image
🧵1/ Definition: These are seizures characterized by "twitching" movements of a body part. "Clonus" is simply considered a repetitive form of "Myoclonus"
2/ The "twitch" is produced by a SYNCHRONIZED brief tetanic contraction of both agonist and antagonist muscle groups, followed by SYNCHRONIZED silent periods. This phenomenon is what causes the twitching or the jerking appearance. sEMG channels covering a pair of forearm flexor muscles (pink) and extensor muscles (blue). Red double-head arrows show the brief synchronized tetanic contraction, followed by synchronized silent periods
Read 17 tweets
Jan 10
SEIZURE SEMIOLOGY #TWEETORIAL
#Epilepsy #Seizure #NeuroX

🧵1. What is the M2e sign?
The M2e sign is a strong lateralizing sign characterized by an ictal arm movement w/ initial elbow flexion, f/b shoulder abduction & external rotation, with contralateral arm being uninvolved.
M2e is also referred to as 'fencing posture'
Image
2. This peculiar posturing or arm movement may or may not occur with a versive head/eye movement. If it does occur with version, it appears as if the patient is looking at their hand. Position 1-4 are sequential representations of the arm movement. Position 3 shows a full M2e. In this case, the version occurred before the M2e. All through 1-3, the right arm is uninvolved.  From: "Epilepsy and Cerebral Localization. A study of the mechanism, treatment and prevention of epileptic seizures: by W. Penfield and T. Erickson, CC Thomas, Springfield, IL 1941
3. The phrase "M2e" was coined by C. Ajmone Marsan and B. Ralston in 1957. They used "M2e" as a key formulation to refer to above-defined ictal arm movement in Metrazol-induced seizures. Image
Read 14 tweets
Dec 7, 2023
EPILEPSY SURGERY #TWEETORIAL

🧵 What are the cortical zones of epilepsy?
The cortical zone theory of epilepsy postulates the following zones- epileptogenic zone, seizure onset zone, early spread zone, irritative zone, symptomatogenic zone & functional deficit zone. #NeuroTwitter Hypothetical organizational schematic representing the cortical zones related to epilepsy
1/ The epileptogenic zone (EZ) is defined as the minimum area of cortex indispensable for seizure production, which when removed (or disconnected) leads to seizure freedom.
Image
Image
2/ The origins of this concept can be traced back to the 19th century when Sir V. Horsley & JH Jackson planned surgeries for epilepsy patients to remove the so-called "discharging lesion". They only used seizure semiology and macroscopic appearance of lesion to guide resection.
Read 18 tweets
Oct 24, 2023
SEIZURE SEMIOLOGY TWEETORIAL

🧵1/ What is a complex motor seizure?

A complex motor sz is a type of motor seizure which is characterized by natural-appearing movements mimicking normal daily life activities e.g. swallowing, lip smacking, gestural etc.
#Neurotwitter #Epilepsy Image
2/ There are two main subtypes- automotor seizures and hypermotor seizures. Some other rarer forms include gelastic, dacrystic, kissing, spitting, verbalization seizures.
Image
Image
3/ Automotor seizure- This is a type of seizure characterized by mainly distal, natural-appearing organized movements- Oroalimentary, gesticulatory, genital & sexual automatisms.
Image
Image
Read 17 tweets
Jul 6, 2023
SEIZURE SEMIOLOGY #TWEETORIAL

🧵1/ What is a dialeptic seizure?

Dialeptic seizure is defined by a peculiar alteration of consciousness in epilepsy, characterized by complete or partial unresponsiveness w/ motor/behavioral arrest AND amnesia.
#Epilepsy #EEG #SeizureSemiology
2/ The term "dialepsis" was proposed in 1998 to identify and classify this peculiar seizure only by semiology. The term "absence" refers to a subtype of dialeptic seizures which has a characteristic EEG pattern of generalized 3Hz spike and wave (Gen epilepsy).



3/ The term is derived from a Greek verb "διαλειπειν" which means "to interrupt", "stand still" or "pass out".

Read 12 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(