3.4 Event Button Workflow, Clinical Testing & Ictal Observation
Key Takeaways
- The event push-button creates a precise time-synchronized digital annotation across EEG recording channels and synchronized digital video streams, enabling rapid re-montaging and targeted post-event analysis.
- Patient and family education must emphasize activating the event marker at the very first subjective warning (aura), rather than waiting for motor convulsions or loss of consciousness.
- Standardized in-room clinical testing during an event must follow an immediate, structured sequence: ensure safety, clear visual obstruction (remove blankets, turn on lights), test verbal responsiveness, give a memory phrase, test language/naming, evaluate motor tone, and check visual fields.
- Testing anterograde memory encoding requires stating an explicit test word/phrase during the ictus (e.g., 'velvet chair') and testing immediate repetition as well as delayed recall at 1, 3, and 5 minutes post-ictally.
- Technologists must utilize structured SBAR (Situation, Background, Assessment, Recommendation) communication and adhere to urgent escalation criteria (seizures >5 min, clusters >3 in 24h, autonomic/respiratory compromise, new semiology) when alerting the on-call epileptologist.
Last updated: August 2026
3.4 Event Button Workflow, Clinical Testing & Ictal Observation
The diagnostic yield of long-term video-EEG monitoring depends directly on the quality of ictal clinical testing performed at the bedside. When a seizure occurs, passive video observation is insufficient; active, standardized neurodiagnostic assessment is mandatory to delineate the patient's level of consciousness, language integrity, memory encoding, and focal motor function. The CLTM technologist must lead event marker management, coordinate bedside interventions with nursing staff, execute structured clinical testing protocols, and communicate urgent findings to the medical team.
1. Event Marker Protocols and Technical Integration
The patient event marker (push-button) is an essential hardware and software interface in digital LTM acquisition systems (Natus, Nihon Kohden, Cadwell, Persyst). When pressed, it injects a synchronous digital pulse across all recording channels, establishes a permanent time-stamped annotation on the EEG review timeline, and flags the corresponding digital video segment for prioritized clinical review.
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| EVENT MARKER & MONITORING WORKFLOW |
| |
| [PATIENT / FAMILY] [LTM MONITORING STATION] [IN-ROOM BED] |
| Presses Push-Button ---> Auditory/Visual Alarm ---> Immediate Room|
| at Earliest Aura Camera Auto-Zoom/Pan Entry & Lights|
| Technologist Video Check Bedside Test |
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Patient and Family Education Protocol:
- Early Activation: Technologists must instruct patients and family members upon admission to press the button at the very first subjective warning (e.g., rising stomach feeling, strange smell, tingling, visual spot, or anxiety). They must not wait for involuntary motor movements or speech difficulty.
- Caregiver Role: If the patient becomes unresponsive or unable to press the marker, family members or bedside sitters must immediately press the button on the patient's behalf and call for the technologist/nurse.
- Hardware Maintenance: Technologists must verify at the start of each shift that the push-button cord is securely connected to the headbox/amplifier, positioned within easy reach of the patient's dominant hand, and transmitting a functional signal to the monitoring software.
2. In-Room Standardized Clinical Testing Protocol
When an event marker is triggered or an automated seizure detection alert sounds, the technologist (or bedside nurse directed by the technologist) must execute the Standardized EMU Clinical Testing Sequence without delay.
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| STANDARDIZED EMU BEDSIDE TESTING SEQUENCE |
| |
| STEP 1: PATIENT SAFETY & AIRWAY |
| - Verify padded side rails UP; position lateral decubitus if vomiting. |
| - Do NOT place anything in mouth; apply O2/suction as needed. |
| |
| STEP 2: AUDIO-VISUAL OPTIMIZATION |
| - Pull blankets below waist (expose all 4 extremities and face). |
| - Turn ON overhead lights; zoom/center video camera. |
| |
| STEP 3: VERBAL RESPONSIVENESS & MOTOR COMMAND |
| - Call patient's name: 'Mr. Smith, can you hear me? Look at me.' |
| - Command: 'Raise your left arm', 'Show me two fingers.' |
| |
| STEP 4: MEMORY PHRASE ENCODING (ANTEROGRADE AMNESIA TEST) |
| - State clearly: 'Remember the phrase: VELVET CHAIR.' (Repeat 3 times). |
| - Ask patient to repeat phrase immediately if able. |
| |
| STEP 5: LANGUAGE & NAMING |
| - Hold up 2 familiar objects in camera view: 'What is this? What is this?' |
| - Phrase repetition: 'Repeat: No ifs, ands, or buts.' |
| - Reading card: 'Read this sentence out loud.' |
| |
| STEP 6: MOTOR TONE, DRIFT & REFLEXES |
| - Bilateral hand grips (assess for unilateral Todd's paresis). |
| - Arm drift (arms outstretched, palms up, eyes closed). |
| |
| STEP 7: POST-ICTAL TESTING SEQUENCE |
| - Orientation: Person, Place, Time, Event. |
| - Recall memory phrase: 'What was the test phrase I told you earlier?' |
| - Assess for post-ictal nose wiping and post-ictal dysphasia. |
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Detailed Testing Phases & Clinical Significance:
Phase A: Safety and Airway Management
- Side Rails: Ensure all bed side rails are elevated and padded.
- Airway & Aspiration Protection: If the patient produces excessive secretions or vomits (ictus emeticus), turn the patient onto their side in the lateral decubitus position to maintain an open airway and prevent aspiration. NEVER insert tongue depressors, airway devices, or fingers into a seizing patient's mouth.
- Supplemental Oxygen: Administer blow-by or nasal cannula oxygen if pulse oximetry falls below 90%.
Phase B: Video and Environmental Optimization
- Remove Visual Obstructions: Immediately pull blankets and top sheets down to the lower abdomen so that all four extremities, trunk, neck, and face are completely visible to the camera.
- Illumination: Switch overhead room lights on (do not leave patient in dark or dimmed room).
- Camera Positioning: Use Pan-Tilt-Zoom (PTZ) controls to frame the patient's entire body, face, and the examiner's hands.
Phase C: Responsiveness and Awareness Testing
- Address the patient by name loudly: "Mrs. Davis, look at me!"
- Issue a simple command: "Hold up two fingers on your right hand."
- Issue a midline axial command: "Stick out your tongue."
Phase D: Memory Encoding (Anterograde Amnesia Assessment)
- Present a standardized, memorable test phrase or unrelated noun: e.g., "VELVET CHAIR", "BLUE ELEPHANT", or "RED BALLOON".
- Repeat the word clearly three times in front of the camera: "Remember the words VELVET CHAIR. I will ask you for them later."
- Ask the patient to repeat it immediately. If the patient repeats the word ictally but cannot recall it post-ictally, it proves ictal speech was intact but anterograde memory consolidation was impaired (classic for mesial temporal lobe involvement).
Phase E: Language and Naming Testing
- Object Naming: Hold two distinct everyday objects directly in the patient's and camera's line of sight (e.g., a pen, a watch, a cup, a dollar bill) and ask: "What is this object called?"
- Phrase Repetition: "Repeat after me: 'No ifs, ands, or buts.'"
- Reading: Hold a printed index card in front of the patient with a simple sentence (e.g., "Close your eyes" or "The sky is blue") and instruct them to read it aloud.
Phase F: Motor Strength and Focal Deficit Testing
- Bilateral Hand Grip: Have the patient squeeze both of the examiner's hands simultaneously to test for asymmetric weakness.
- Pronator Drift: Ask the patient to hold both arms extended with palms facing up and eyes closed for 10 seconds (downward drift indicates contralateral pyramidal tract dysfunction / Todd's paresis).
Phase G: Post-Ictal Testing
- Orientation: Ask: "What is your name? Where are you right now? What year is it? What were you doing before this happened?"
- Delayed Word Recall: Ask: "What was the special phrase I asked you to remember during the event?"
- Spontaneous Recall: Intact memory consolidation -> awareness was preserved during testing.
- Cued Recall / Recognition: If failed, offer a category cue ("It was a piece of furniture") or 3-choice multiple choice ("Was it velvet chair, purple kangaroo, or green apple?").
- Documentation: Record the exact post-ictal time (in minutes/seconds) when the patient returns to baseline orientation and language fluency.
3. EMU Nursing, Staff Coordination & Urgent Escalation Criteria
Maintaining patient safety in the EMU requires seamless interprofessional collaboration between CLTM technologists, EMU nurses, and attending epileptologists.
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| EMU URGENT CLINICAL ESCALATION CRITERIA |
| |
| 1. STATUS EPILEPTICUS: Convulsive seizure lasting >5 MINUTES, or focal |
| seizure with impaired awareness lasting >10 minutes without recovery. |
| |
| 2. SEIZURE CLUSTER: >=2 to 3 convulsive seizures in 24 hours (or exceeding |
| individual patient-specific safety parameters). |
| |
| 3. NEW SEMIOLOGY: Emergence of uncharacterized seizure phenotype, prolonged |
| apnea, or cardiac arrhythmia (sustained bradycardia, asystole >3s). |
| |
| 4. PROLONGED ENCEPHALOPATHY: Failure to regain baseline mental status |
| within 30-45 minutes post-seizure. |
| |
| 5. TRAUMA / FALL: Any patient fall, physical injury, or head strike. |
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Structured SBAR Communication Model
When alerting the on-call epileptologist regarding urgent events, technologists must use the SBAR framework:
- S (Situation): "This is Technologist Smith in the EMU. Patient in Room 412 had a 6-minute generalized convulsion that required rescue lorazepam."
- B (Background): "The patient is a 34-year-old female with drug-resistant left temporal lobe epilepsy admitted for pre-surgical evaluation, currently on 50% reduced levetiracetam."
- A (Assessment): "The seizure began with left temporal rhythmic theta, progressed to right asymmetric tonic posturing (Figure-4) and bilateral convulsion. Oxygen saturation dropped to 82% but recovered to 96% on 4L nasal cannula. Patient remains deeply somnolent with right-sided Todd's hemiparesis."
- R (Recommendation): "I recommend immediate physician bedside evaluation, resuming baseline levetiracetam dosing, and ordering a STAT post-ictal ECG."
Test Your Knowledge
According to standard American Epilepsy Society (AES) and neurodiagnostic guidelines, what seizure duration threshold defines convulsive Status Epilepticus (Time t1), requiring immediate emergency protocol activation and rescue medication administration?
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Test Your Knowledge
What crucial instruction should the technologist provide to the patient and their family regarding the use of the event push-button upon admission to the EMU?
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B
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D
Test Your Knowledge
When entering the room of a patient actively having a generalized convulsion in the EMU, what is the most appropriate initial nursing and technologist intervention?
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D
Test Your Knowledge
Why is it essential for the technologist to state a specific memory test phrase (e.g., 'velvet chair') during an active seizure and test for its recall post-ictally?
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D