Presentation of Partial (Focal) Seizures

Terminology and Classification

Pathophysiology

• Scar tissue pulling on adjacent neurons
• Tumors compressing cortical areas
• Destroyed brain tissue
• Congenitally disordered local circuitry

• Guyton and Hall Textbook of Medical Physiology

1. Focal Aware Seizures (Simple Partial Seizures)

Motor symptoms

• Jacksonian march: rhythmic clonic jerking that spreads progressively along the motor homunculus (classically starting at the mouth or hand, then marching down the limb). Activity is contralateral to the epileptic hemisphere.
• Focal tonic stiffening of a limb
• Versive head/eye turning (contralateral)

Somatosensory / Special sensory symptoms

• Tingling, numbness, or electric sensations (contralateral body)
• Visual: flashing lights, formed hallucinations (occipital lobe)
• Auditory: buzzing, tones, or complex sounds (lateral temporal/Heschl gyrus)
• Olfactory/gustatory auras (usually mesial temporal; also with tumoral etiology)
• Vertiginous auras (posterior temporal or parietal)

Autonomic symptoms

• Epigastric rising sensation (most common aura in temporal lobe epilepsy)
• Pallor, flushing, piloerection ("gooseflesh"), tachycardia, palpitations

Psychic (cognitive/emotional) symptoms

• Fear or anxiety (amygdala involvement)
• Deja vu or jamais vu (hippocampal/temporal)
• Depersonalization, dream-like states
• Forced thinking, speech arrest (dominant hemisphere)

Auras

• Bradley and Daroff's Neurology in Clinical Practice

2. Focal Impaired Awareness Seizures (Complex Partial Seizures)

Typical features:

• May begin with an aura (as above), followed by loss of awareness
• Behavior arrest: sudden cessation of ongoing activity, staring
• Automatisms: semi-purposeful, stereotyped movements, the patient has no recollection of
  • Oroalimentary: lip smacking, chewing, swallowing (most common)
  • Manual: fumbling, picking, rubbing hands
  • Ambulatory: walking, trying to stand up
• Duration: typically 1-2 minutes (range 30 seconds to 3 minutes)
• Postictal phase: gradual return to consciousness with confusion, fatigue, and possible amnesia (contrast with absence seizures, which terminate abruptly)

Key comparison - Complex Partial vs. Absence Seizures:

• Bradley and Daroff's Neurology in Clinical Practice

3. Focal to Bilateral Tonic-Clonic Seizures (Secondary Generalization)

1. Versive head turning contralateral to the hemisphere of onset
2. Figure-of-four posturing: contralateral arm extended, ipsilateral arm flexed - lateralizes to the hemisphere contralateral to the extended arm
3. Bilateral tonic phase (may be asymmetrical)
4. Clonic phase: decreasing frequency of jerks over time, may end asymmetrically
5. Postictal period: limpness, stertorous (snoring) respiration, gradual recovery

• Bradley and Daroff's Neurology in Clinical Practice

4. Localization-Based Presentations

Temporal Lobe (most common)

• Epigastric rising aura (most common)
• Fear, anxiety, deja/jamais vu
• FIAS with oroalimentary automatisms and contralateral arm dystonic posturing
• Ipsilateral extremity automatisms (contralateral arm is "frozen" in dystonia)
• Postictal aphasia after dominant temporal lobe seizures

• Auditory auras, vertigo, complex visual hallucinations
• Shorter duration, greater tendency to secondarily generalize

Frontal Lobe

• Motor cortex: focal clonic activity +/- Jacksonian march
• Supplementary motor area (SMA): asymmetrical tonic/postural seizures (fencing posture), usually with preserved consciousness despite bilateral motor involvement - this is an important exception to the rule; these are short, often arise from sleep, occur in clusters
• Anterior cingulate/hypermotor: thrashing, kicking, cycling leg movements, may appear bizarre
• Frontal lobe seizures: brief, often nocturnal, may have minimal postictal state

Parietal Lobe

• Contralateral somatosensory symptoms (tingling, numbness, pain)
• May spread to produce motor features

Occipital Lobe

• Contralateral visual phenomena (phosphenes, scotomas, formed hallucinations)

5. EEG Findings

• Interictal: focal spikes, sharp waves, or focal slowing over the epileptogenic zone
• Ictal: focal high-frequency rhythmic discharge evolving in frequency/amplitude over time
• Complex partial seizures: focal epileptic discharges or focal slowing (contrast with 3 Hz spike-and-wave of absence seizures)
• Psychomotor (complex partial) seizures: low-frequency rectangular wave 2-4/sec with superimposed 14/sec waves

Summary

Bulbar Palsy and Pseudobulbar Palsy

Anatomy: What is the "Bulb"?

• Tongue (XII - hypoglossal)
• Pharynx and larynx (IX, X - glossopharyngeal, vagus)
• Palate (X)
• Sternocleidomastoid and trapezius (XI - accessory)
• Jaw and face (V, VII - technically outside the medulla but included clinically)

1. Bulbar Palsy (LMN)

Definition

Causes

• Motor neurone disease (progressive bulbar palsy - most common current cause)
• Guillain-Barre syndrome (acute)
• Poliomyelitis (historical)
• Diphtheritic neuropathy
• Syringobulbia
• Brainstem tumors, infarcts affecting nuclei directly
• Kennedy disease (bulbospinal muscular atrophy)
• Myasthenia gravis (neuromuscular junction - mimics bulbar palsy)

Clinical Features

• Nasal dysarthria (palatal weakness - air escapes through nose)
• Difficulty with lingual consonants (r, n, l), labial consonants (b, m, p, f), dental (d, t) and palatal (k, g) consonants
• Syllables lose clarity and run together until speech becomes unintelligible
• Voice may be "wet" sounding due to pooled secretions
• Eventually aphonia

• Initial difficulty with fluids (coughing, spluttering)
• Progresses to all consistencies
• Nasal regurgitation of liquids (palatal failure)
• Aspiration - repeated aspiration pneumonia
• Food lodges between cheek and teeth; bolus cannot be propelled into esophagus

• Atrophy (wasting - shriveled, lies on floor of mouth)
• Fasciculations - visible wriggling movements; may also be seen in facial muscles and palpated in masseter
• Weakness of tongue movement

• Weakness of jaw closure and opening
• Jaw jerk: absent or reduced (LMN)

• Absent or reduced movement on phonation
• Absent gag reflex

• Facial muscle weakness and sagging (lower face)
• Chin fasciculations may be visible

• Muscle wasting/atrophy
• Fasciculations
• Hypotonia (flaccid)
• Absent/reduced reflexes (jaw jerk, gag reflex)
• No emotional lability
• Adams and Victor's Principles of Neurology, Scott-Brown's Otorhinolaryngology

2. Pseudobulbar Palsy (UMN)

Definition

Why Bilateral Lesions Are Required

Causes

• Bilateral cerebrovascular disease (bilateral capsular lacunar infarcts - most common; successive strokes)
• Multiple sclerosis (bilateral plaques)
• Motor neurone disease (UMN predominant - primary lateral sclerosis)
• Progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome)
• Bilateral subdural hematomas
• Severe traumatic brain injury

Clinical Features

• Spastic dysarthria - slow, strained, "hot potato" quality (as if food too hot in mouth)
• Harsh, strangled voice
• Slurred, monotonous, effortful speech
• Low pitch, reduced volume

• Dysphagia - present but generally milder than in bulbar palsy
• Aspiration risk still present
• Saliva may accumulate in mouth (pooling)

• Small, spastic - slow movements
• No atrophy
• No fasciculations
• Tongue moves slowly but is not wasted

• Brisk jaw jerk (exaggerated) - pathological
• "Bulldog reflex" - jaw snaps shut involuntarily on mouth opening attempt (rare, severe cases)
• Jaw clonus may be elicited

• Hyperactive gag reflex
• Brisk jaw jerk
• Snout reflex (pursing of lips when tapped)
• Suck reflex (regression of primitive reflexes)
• Forced/pathological yawning

• Involuntary, uncontrollable episodes of crying and laughing that are disproportionate to or incongruent with the patient's emotional state
• Also called: emotional incontinence, pathological laughter and crying (PLAC), involuntary emotional expression disorder
• The patient cannot control these outbursts and is often embarrassed
• In severe cases, laughing and crying are the only available forms of emotional expression - intermediate expressions (smiling, frowning) are lost
• Laughter and crying may merge into each other

1. Corticobulbar pathway (posterior internal capsule limb) - controls volitional facial/vocal movements
2. Anterior pathway (just rostral to genu of internal capsule) - contains facilitatory and inhibitory fibers

• Adams and Victor's Principles of Neurology

• Bilateral limb spasticity and hyperreflexia
• Bilateral extensor plantar responses (Babinski)
• Small, brisk steps (marche à petits pas) if bilateral anterior circulation disease
• Cognitive slowing if severe bilateral white matter disease

3. Comparison Table

4. Mixed Bulbar + Pseudobulbar Palsy

5. Key Points for Clinical Distinction

• Fasciculations + wasting = bulbar palsy (LMN) until proven otherwise
• Emotional lability (crying/laughing) = pseudobulbar palsy (UMN) - this does not occur in pure LMN lesions
• Brisk jaw jerk = UMN (pseudobulbar); absent jaw jerk = LMN (bulbar)
• A single hemisphere stroke rarely causes persistent bulbar palsy - bilateral lesions required for pseudobulbar
• Myasthenia gravis is the most important differential for bulbar palsy (especially in the elderly) - the fatigability and variability should help distinguish, but atypical cases can be confusing

Why the Jaw Jerk Is Exaggerated in UMN Lesions

The Jaw Jerk Reflex Arc

• Stretch is detected by muscle spindle Ia proprioceptive fibers in the masseter
• These Ia fibers travel in the mandibular division (V3) of the trigeminal nerve
• Uniquely, their cell bodies lie inside the CNS in the mesencephalic nucleus of the trigeminal nerve in the midbrain - the only case where primary sensory neurons reside within the CNS rather than in a peripheral ganglion
• Their central processes descend a short distance within the brainstem to synapse directly in the motor nucleus of CN V in the mid-pons

• Motor neurons of the trigeminal motor nucleus (mid-pons)
• Axons exit via the mandibular nerve (V3)
• Innervate the masseter and temporalis → jaw closes

• Neuroanatomy Through Clinical Cases; Adams and Victor's Principles of Neurology

Why It Is Normally Minimal or Absent

Why It Becomes Exaggerated with a UMN Lesion

1. The descending inhibitory control is removed - the trigeminal motor nucleus is released from supraspinal suppression
2. The motor neurons of CN V become hyperexcitable (disinhibited)
3. Even a small jaw stretch now triggers a brisk, exaggerated contraction of the masseters - jaw snaps shut

"Lesions anywhere along this reflex arc result in depression of the ipsilateral jaw reflex, whereas bilateral supranuclear lesions result in an accentuated response."

• Localization in Clinical Neurology, 8e

Why Bilateral Lesions Are Required

Summary Diagram

Normal:
Motor cortex (bilateral)
       |
Corticobulbar tracts  ──► Trigeminal motor nucleus (INHIBITED)
                                    ↑
Mesencephalic nucleus ──► (weak reflex response)

UMN Lesion (bilateral corticobulbar damage):
Motor cortex  ✗
       |
Corticobulbar tracts  ──✗──► Trigeminal motor nucleus (DISINHIBITED / hyperexcitable)
                                    ↑
Mesencephalic nucleus ──► BRISK jaw jerk (masseter snaps shut)

UMN vs. LMN Lesion: Complete Comparison

Anatomy First

Core Comparison Table

• Harrison's Principles of Internal Medicine 22e; Neuroanatomy Through Clinical Cases

1. Tone

• Velocity-dependent increase in tone (resistance increases with faster passive stretch)
• "Clasp-knife" phenomenon - initial resistance suddenly gives way
• Affects antigravity muscles predominantly: flexors in the arm, extensors in the leg
• Due to loss of descending inhibitory control on the stretch reflex arc

• Muscle tone is reduced or absent
• Limb is floppy, soft
• Due to loss of gamma motor neuron input that maintains spindle tension

2. Reflexes

• Deep tendon reflexes (DTRs) are exaggerated - disinhibited stretch reflex arcs
• Clonus - rhythmic oscillations on sustained stretch (e.g., ankle clonus)
• Pathological reflexes present:
  • Babinski sign (extensor plantar - great toe dorsiflexes, toes fan out)
  • Hoffmann sign (finger flexion on flicking middle fingernail)
  • Snout, suck, grasp reflexes (frontal release signs)
• Superficial reflexes lost: abdominal reflexes, cremasteric reflex

• DTRs are reduced or absent - the reflex arc itself is broken
• No pathological reflexes
• Plantar response may be absent or flexor (normal direction)

Important exception: Immediately after an acute UMN lesion (e.g., cord transection, acute stroke), there is a period of spinal shock - flaccidity, hyporeflexia, and absent Babinski. Spasticity and hyperreflexia develop gradually over hours to weeks as the spinal cord adapts.

3. Wasting and Fasciculations

• The trophic influence of the motor neuron on the muscle fiber is lost
• Denervated muscle fibers atrophy

4. Distribution of Weakness

• Distal muscles affected more than proximal
• Upper limb: extensors weaker than flexors (extensors are "anti-gravity" in the arm - so they bear the pyramidal tract distribution)
• Lower limb: flexors weaker than extensors (e.g., foot drop)
• This is the pyramidal distribution of weakness
• Axial (trunk) movements are relatively spared unless bilateral or severe
• Corticobulbar lesions preferentially affect: lower face, tongue; spares upper face, extraocular muscles, jaw

• Distribution matches the anatomical territory of the affected nerve, root, or anterior horn segment
• Nerve lesion: follows peripheral nerve territory
• Root lesion: dermatomal/myotomal distribution
• Anterior horn: segmental pattern

5. UMN Syndrome: Positive vs. Negative Features

6. Common Causes

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