What Is qEEG Brain Mapping and What Can It Tell Us?

If you've been recommended a qEEG brain map, you may be wondering what the test actually measures and what the results can tell you about your brain.

Quantitative electroencephalography (qEEG) is a non-invasive method of recording and quantitatively analyzing the brain's electrical activity. Sensors placed on the scalp detect electrical signals generated by brain activity, while specialized software analyzes characteristics and patterns within the recorded data.

Unlike an MRI or CT scan, qEEG does not produce an image of the physical structure of your brain. Instead, it provides information about patterns of electrical brain activity.

This information may be incorporated into a broader clinical or neuropsychological assessment and can also be used in some settings to help inform neurofeedback treatment protocols.

What Is qEEG?

qEEG stands for quantitative electroencephalography.

To understand qEEG, it helps to first understand EEG.

An electroencephalogram (EEG) records electrical activity in the brain through electrodes placed on the scalp. These electrodes detect electrical signals associated with neuronal activity and allow clinicians to examine patterns of brain activity.

qEEG takes recorded EEG data a step further by using mathematical and statistical methods to analyze characteristics of those signals.

Depending on the method being used, the analysis may examine activity within different frequency ranges, including:

• Delta
• Theta
• Alpha
• Beta

The results can then be represented numerically and visually, including as topographical maps that show how particular measures of electrical activity are distributed across different scalp locations.

qEEG vs. EEG: What's the Difference?

What Happens During a qEEG Brain Mapping Session?

The procedure itself is non-invasive.

Sensors or electrodes are positioned at specific locations on the scalp to record electrical brain activity. The electrodes only record signals; they do not send electricity into the brain.

Depending on the assessment protocol, recordings may be taken while you are sitting quietly with your eyes open and closed. Some protocols may also incorporate specific tasks.

During the recording, it is important to identify potential artifacts—signals caused by factors such as eye movements, blinking, muscle activity or movement—so they are not mistakenly interpreted as brain activity.

After the recording is completed, appropriate portions of the EEG data can be processed and analyzed using specialized software.

The clinician then interprets those findings within the context of the reason for the assessment, the person's symptoms and other available clinical information.

For more information about the assessment itself, visit our Quantitative Electroencephalogram (qEEG) service page .

What Can a qEEG Brain Map Show?

A qEEG provides a quantitative way of examining patterns within electrical brain activity.

Brainwave activity

qEEG can measure electrical activity within different frequency ranges and examine how strongly certain frequencies are represented.

Regional patterns

The analysis can examine how particular measures of electrical activity vary across different areas of the scalp.

Relationships between signals

Some qEEG analyses evaluate relationships between electrical signals recorded at different electrode locations.

Comparison with reference data

Certain qEEG systems compare measurements with normative reference databases. Factors such as age, recording conditions, data quality and the characteristics of the reference population need to be considered when interpreting these comparisons.

These measurements can provide additional information about patterns of brain function, but their meaning depends heavily on the clinical context.

Can qEEG Diagnose ADHD?

Not by itself.

Researchers have identified EEG characteristics that may occur more frequently in some people with Attention-Deficit/Hyperactivity Disorder (ADHD). However, ADHD is a heterogeneous condition, meaning that people with the same diagnosis can have very different clinical and neurophysiological profiles.

A 2024 systematic review published in Pediatrics examined 231 studies evaluating diagnostic tools for ADHD in children and adolescents, including EEG and neuroimaging. Although several tools showed promising results, diagnostic performance varied considerably and the overall strength of evidence was generally low.

The researchers concluded that reliable ADHD diagnosis requires clinical judgment together with appropriate standardized assessments and information from multiple sources.

For this reason, qEEG should not be used as a stand-alone ADHD test.

Instead, when clinically appropriate, qEEG findings can be considered alongside information such as:

• Clinical interviews
• Developmental history
• ADHD rating scales
• Attention testing
• Executive-function testing
• Cognitive assessment
• Medical history
• Functional difficulties in everyday life

At Neurotherapy Montreal, our Comprehensive Adult ADD/ADHD Assessment combines multiple sources of information to develop a more complete clinical picture.

This broader approach is particularly important because ADHD symptoms can overlap with anxiety, depression, sleep disorders, learning difficulties and other conditions. You can learn more about this overlap in our article ADHD vs. Anxiety: How to Tell the Difference .

Can qEEG Diagnose Anxiety or Depression?

Again, not on its own.

Research continues to investigate EEG patterns associated with different psychiatric, neurological and cognitive conditions. However, there is considerable variation between individuals, and similar patterns of brain activity may occur in people with different symptoms or diagnoses.

It would therefore be inappropriate to interpret a particular qEEG pattern as automatically meaning:

Brain function is considerably more complex.

qEEG findings are most useful when interpreted by a qualified professional alongside the person's symptoms, history and other assessment results.

How Is qEEG Used With a Neuropsychological Assessment?

One of the most useful ways to think about qEEG is as one source of information within a larger assessment.

A comprehensive neuropsychological or ADHD evaluation may include:

• A detailed clinical interview
• Medical and developmental history
• Educational and occupational history
• Standardized questionnaires
• Attention testing
• Memory testing
• Executive-function testing
• Processing-speed measures
• Other cognitive assessments

When qEEG is included, it adds information about patterns of electrical brain activity.

The different components answer different questions.

Cognitive testing, for example, may reveal that someone has difficulty sustaining attention or inhibiting responses. Clinical history may reveal when those problems began and how they affect everyday life. qEEG may provide additional physiological information about electrical brain activity.

For individuals experiencing changes in memory, concentration, decision-making or other cognitive abilities, a dedicated Assessment of Cognitive Functions may also be appropriate depending on the clinical situation.

How Can qEEG Be Used With Neurofeedback?

qEEG and neurofeedback are related, but they are not the same thing.

A simple distinction is:

Neurofeedback uses real-time information about brain activity to provide feedback to the individual. Through repeated training sessions, the goal is to help the person learn to modify selected patterns of brain activity.

In some approaches, qEEG findings may be used to help clinicians identify patterns that can inform an individualized neurofeedback protocol.

Research into neurofeedback continues to evolve, and results vary according to the condition being treated, the protocol being used and the quality of the available evidence. Recent reviews continue to investigate the potential role of qEEG-informed neurofeedback, including in ADHD.

It is therefore important to evaluate neurofeedback recommendations in the context of the individual's symptoms, clinical assessment and treatment goals rather than assuming that one protocol is appropriate for everyone.

Is qEEG Brain Mapping Safe?

EEG recording is generally considered safe and non-invasive.

The electrodes placed on the scalp record electrical activity—they do not deliver electricity into the brain.

The procedure:

• Does not use radiation
• Does not involve injections
• Is generally painless
• Records electrical signals through sensors placed on the scalp

Some people may experience temporary minor skin irritation from electrode adhesives or conductive materials.

Who Might Benefit From qEEG Brain Mapping?

Whether qEEG is appropriate depends on the reason for the assessment and the individual clinical situation.

It may be incorporated into a broader evaluation when a clinician wants additional information about patterns of electrical brain activity.

At Neurotherapy Montreal, qEEG may be considered as part of a broader approach for individuals experiencing concerns involving areas such as:

• Attention and concentration
• Cognitive functioning
• Persistent post-concussion symptoms
• Neurofeedback assessment and treatment planning

For people experiencing ongoing symptoms following a concussion, Neurotherapy Montreal also offers a Comprehensive Assessment of Post-Concussion Symptoms that examines cognitive, physical and emotional factors.

The decision to use qEEG should be based on the clinical question being investigated rather than simply on the presence of a particular symptom or diagnosis.

What Can't qEEG Tell You?

Understanding the limitations of qEEG is just as important as understanding its potential uses.

A qEEG brain map cannot, by itself:

• Diagnose ADHD
• Diagnose anxiety or depression
• Explain every symptom a person experiences
• Replace a clinical evaluation
• Replace neuropsychological testing when such testing is indicated
• Predict with certainty how someone will respond to treatment

Interpretation also depends on the quality of the original EEG recording and the methods used to process the data. Technical standards emphasize appropriate EEG acquisition, artifact management, visual inspection and careful processing as important elements of reliable qEEG analysis.

Key Takeaway

qEEG brain mapping provides a quantitative method for examining patterns in the brain's electrical activity.

It can offer additional information about brain activity and may complement clinical and neuropsychological assessments or help inform neurofeedback planning in appropriate cases.

However, a brain map is not a diagnosis.

The most meaningful interpretation comes from combining qEEG findings with symptoms, medical and developmental history, cognitive testing and professional clinical judgment.

For individuals experiencing persistent difficulties with attention, concentration, cognitive functioning or other neurological concerns, a comprehensive assessment can help determine which evaluation methods are appropriate and provide a clearer understanding of the factors contributing to their symptoms.

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