temporal intermittent rhythmic delta activity
Also written as: TIRDA
A specific EEG pattern of rhythmic 1.5-2.5 Hz activity over the temporal regions, often indicating temporal lobe pathology.
Full Definition
Temporal Intermittent Rhythmic Delta Activity (TIRDA) is a distinctive EEG pattern characterized by rhythmic delta frequency activity (1.5-2.5 Hz) that appears intermittently over one or both temporal regions. TIRDA typically occurs in runs lasting several seconds and is often considered a surrogate marker for temporal lobe epilepsy, even in the absence of overt epileptiform discharges. The pattern may be unilateral, suggesting focal pathology, or bilateral. TIRDA is thought to represent cortical-subcortical dysfunction and can be seen in various conditions affecting the temporal lobe including hippocampal sclerosis, tumors, or other structural abnormalities. Clinical editors should recognize TIRDA as a significant abnormal finding that warrants clinical correlation and often further investigation.
Usage
Usage note: May be abbreviated as TIRDA; specify laterality and relationship to activation procedures.
In Context
- "Left temporal intermittent rhythmic delta activity was noted throughout the recording, suggesting temporal lobe pathology." — EEG interpretation report
- "Bilateral TIRDA appeared during hyperventilation, indicating bitemporal dysfunction." — Clinical neurophysiology report