EEG-Based Differentiation of AuDHD, ADHD, and ASD

EEG-Based Differentiation of AuDHD, ADHD, and ASD at F3, F4, and Fz (Eyes Closed)
Introduction
In neurofeedback and EEG analysis, identifying patterns linked to specific conditions is crucial for accurate diagnosis and treatment. This document outlines how theta and alpha frequency behaviors in the frontal midline (F3, F4, and Fz) during eyes-closed states can help distinguish between AuDHD (Autistic ADHD), ADHD, and ASD.

These patterns provide insight into how the brain processes information internally, its capacity for engagement, and the challenges faced in transitioning between rest and active focus.

Understanding Theta and Alpha Frequencies
Theta Waves (4–8 Hz): Associated with internal focus, creativity, and daydreaming. Elevated theta during tasks requiring attention can signal cognitive inefficiency or disengagement.
Alpha Waves (8–12 Hz): Typically linked to relaxed, wakeful states. Alpha waves are most dominant during eyes-closed relaxation and tend to decrease during cognitive engagement, especially in the frontal regions. Low alpha (7.5–9 Hz) signifies relaxed but alert states, while high alpha (closer to 12 Hz) relates to more active engagement and alertness.
1. AuDHD (Autistic ADHD) Pattern at F3, F4, and Fz (Eyes Closed)
Theta Frequencies: 1.6 Hz / 5.6-5.8 Hz
Low Theta (1.6 Hz): This frequency is close to the delta range, indicating under-arousal and sluggish cognitive processing. The presence of low theta in AuDHD reflects a tendency toward internal disengagement and cognitive difficulties, which are common in both ADHD and autism.

Mid Theta (5.6-5.8 Hz): This range is characteristic of daydreaming or inattention, which is prominent in ADHD. When seen in individuals with AuDHD, it signifies difficulty with sustained attention and cognitive drift, where the brain is not fully engaged in the external environment.

Alpha Frequencies: Unstable or Low Presence
Alpha Not Sticking: The lack of a dominant alpha frequency (especially around 7.5 Hz) suggests a brain that isn’t transitioning smoothly between rest and active engagement. In AuDHD, this reflects the brain’s difficulty in regulating attention, combining symptoms from both ADHD and ASD. The absence of stable alpha implies that the brain is oscillating between disengagement and over-processing.
Interpretation:
The combined presence of low theta (1.6 Hz) and mid-theta (5.6-5.8 Hz), alongside unstable alpha, suggests that the brain is alternating between under-arousal (common in autism) and cognitive drift (characteristic of ADHD). This indicates AuDHD, where individuals face both inattention and social processing challenges, reflective of both conditions.

2. ADHD Pattern at F3, F4, and Fz (Eyes Closed)
Theta Frequencies: 1.6 Hz / 5.6-5.8 Hz
Low Theta (1.6 Hz): This indicates cognitive under-arousal, commonly seen in ADHD, where individuals struggle with sustained attention and often appear mentally sluggish or easily distracted.

Mid Theta (5.6-5.8 Hz): The dominance of mid-theta signifies inattention and mind-wandering. This is a classic marker for ADHD, where individuals experience difficulty staying focused on tasks, especially during restful states like eyes-closed EEG.

Alpha Frequencies: 7.5 Hz (Low Alpha)
Alpha at 7.5 Hz: When low alpha dominates around 7.5 Hz, it indicates the brain is not fully engaging with external tasks. In ADHD, this pattern of stuck alpha reflects difficulty transitioning from rest to active engagement, contributing to symptoms of inattention and cognitive inefficiency.
Interpretation:
When you observe theta at 1.6 / 5.6-5.8 Hz and low alpha at 7.5 Hz, it strongly suggests ADHD. The combination of high theta and a lack of alpha engagement signifies a brain that struggles with inattention and slow cognitive processing, classic symptoms of ADHD. The inability to shift into faster beta frequencies reflects a persistent state of disengagement during tasks requiring focus.

3. ASD (Autism Spectrum Disorder) Pattern at F3, F4, and Fz (Eyes Closed)
Theta Frequencies: 7.5 Hz
Theta Sticking at 7.5 Hz: This is a higher theta frequency bordering on the low alpha range. In individuals with ASD, the dominance of high theta during restful states suggests a brain that is over-processing internally but failing to engage externally. This pattern aligns with common ASD traits, such as social withdrawal, internal focus, and difficulty engaging with external stimuli.
Alpha Frequencies: 7.5 Hz (Low Alpha)
Low Alpha Sticking at 7.5 Hz: The persistence of low alpha at 7.5 Hz in ASD reflects a blurring of boundaries between cognitive states. The brain is stuck in a mode that is neither fully engaged nor fully relaxed, indicating difficulties in transitioning from internal processing to external engagement. This is consistent with the cognitive rigidity often seen in individuals with autism, where they may struggle to adapt to new information or changes in environment.
Interpretation:
When both theta and alpha hover around 7.5 Hz, it suggests ASD. The dominance of these frequencies in the frontal midline regions (F3, F4, Fz) reflects an individual who is focused internally, with reduced engagement in external tasks. This pattern is typical of autism, where the brain remains stuck in a state of self-referential processing and fails to shift to task-oriented cognition.

Key Differentiation Factors
Theta Patterns:

ADHD: Theta predominantly hovers at 5.6-5.8 Hz, indicating inattention and cognitive drift.
ASD: Theta sticks around 7.5 Hz, suggesting internal focus and cognitive disengagement.
AuDHD: Theta fluctuates between low theta (1.6 Hz) and mid-theta (5.6-5.8 Hz), combining features of both ADHD and ASD.
Alpha Activity:

ADHD: Low alpha (7.5 Hz) is present but shows difficulty in engagement, often linked to cognitive inefficiency.
ASD: Alpha at 7.5 Hz is persistent, indicating difficulty transitioning between internal and external focus.
AuDHD: Alpha is unstable, with no dominant frequency, reflecting the combined challenges of inattention and difficulty in cognitive regulation.
Conclusion
By visually tracking theta and alpha frequency behaviors at F3, F4, and Fz during eyes-closed states, you can effectively differentiate between AuDHD, ADHD, and ASD.

In AuDHD, the presence of both low and mid-theta, with an absence of dominant alpha, highlights the shared cognitive and attentional struggles of both ADHD and ASD.
In ADHD, the consistent presence of mid-theta (5.6-5.8 Hz) and low alpha reflects the typical inattentive and sluggish processing seen in this condition.
In ASD, the combination of high theta and low alpha dominance at 7.5 Hz suggests cognitive rigidity and internal focus, common in individuals on the autism spectrum.
These patterns allow you to rapidly assess these conditions in real-time, even before formal quantitative analysis is performed, providing valuable insights for neurofeedback protocol development and clinical decision-making.