What is Breach Rhythm?
The breach rhythm, also known as the breach effect, is a harmless pattern that could appear on an electroencephalogram (EEG) test. An EEG is a non-surgical test that measures the activity of brain cells. The pattern shows high voltage and can often look spiky and irregular. These characteristics might look like the pattern that shows up with epilepsy, but it’s actually caused by an abnormality in the skull.
This breach rhythm could happen from a focal skull defect, which is a localised defect in the skull, for instance, after a surgery known as a craniotomy. This defect can lead to an increase in the size of alpha, beta, and mu rhythms, causing the breach effect. Keep in mind that it might be tough to tell the difference between the breach rhythm and actual epileptic activity happening in the same area. The breach rhythm typically has sharp lines and irregular patterns, usually occurring at a frequency of 6 to 11 Hz, but it might be associated with faster or slower wave activities. Misinterpretation, whether thinking there’s epilepsy when there isn’t or missing it, can have significant effects clinically.
Understanding the difference between regular EEG variants and pathological ones is crucial. An EEG variant that seems benign or harmless might be mistaken for epileptiform activity. The breach rhythm, a benign variant, is typically localized, asymmetrical, and shows high-voltage activity on the EEG.
It often appears like an arch and might sometimes look spiky. It may show up as an irregular rhythm, sometimes associated with sharper activity. You can easily identify a breach rhythm when it occurs in serial trains. However, single, spike-like, or sharp-lined waveforms could be mistaken for epileptic activity. To avoid confusion, it’s important to compare these waveforms with the rhythmic activity that makes up the breach rhythm. If they are distinct, then there may be a need to suspect brain damage. If the breach rhythm is located over the central region, it can be affected by physical movement due to the presence of an underlying normal mu activity. Alternatively, the breach rhythm can sometimes continue during sleep and appear as a voltage increase in spindles during stage 2 of sleep.
What Causes Breach Rhythm?
The “breach effect” is what happens when a portion of the skull is missing or damaged, for instance, following a surgical procedure on the brain. Normally, the skull acts as a sort of filter for the brain’s electrical activity, dulling some of the higher frequencies. However, if there’s a gap or “bony defect” in the skull, the electrical activities like alpha, beta, and mu rhythms are amplified in or around the region of this gap.
This increased frequency and intensity of the electrical activities are due to a reduction in electrical resistance, resulting from the missing portion of the skull. Smaller gaps, such as those caused by a small drill hole used in surgery, are less likely to produce a breach effect, because the area scanned by each electrode is larger than the hole.
In some instances, the breach rhythm could change based on the operation of the underlying brain tissue. For example, there have been observations that the breach rhythm in a patient with a history of seizures was suppressed until antiseizure medication was administered and seizure patterns were under control.
In certain cases, changes to the breach rhythm can be an early sign of cancer progression, as evidenced in some reports of cases involving a type of brain tumor known as astrocytoma. There have also been cases where the breach rhythm was found on a single lesion on the skull caused by multiple myeloma, a type of bone marrow cancer.
Risk Factors and Frequency for Breach Rhythm
Breach rhythm is an uncommon harmless variation that shows up in an EEG, or an electrical brain scan. Currently, we aren’t sure about the exact statistics or who it affects most.
Signs and Symptoms of Breach Rhythm
It’s important to gather information about any previous surgeries or injuries related to the skull or brain. Sometimes, a missing piece of the skull can be hard to spot because an acrylic material may have been used to fill the gap. A technique called bipolar montage can be helpful in identifying this, thanks to its high capability to detect details.
Testing for Breach Rhythm
Identifying a specific pattern called ‘breach rhythm’ when interpreting EEG (which is a test that measures and records the electrical activity in your brain) is very significant. This is because it could be wrongly interpreted as signs of epilepsy.
So, it’s essential for doctors to ask you about any previous surgeries you’ve had and if you ever had a head injury. This is to help them figure out if there’s a chance that a breach rhythm might be present. However, merely feeling your scalp may not be enough. A breach rhythm is usually seen over areas of the skull that have defects, and it ends suddenly beyond the edge of the defect. This rhythm is best seen by bipolar montage, a type of EEG recording, because it shows more detailed images.
Breach rhythms are usually strong wave patterns that range between 6 to 11 Hz, often mixed with waves of higher and lower frequencies. These rhythms often look a lot like something called epileptiform activity, which is a kind of abnormal brain wave pattern often seen in people with epilepsy. However, pure breach rhythms do not have any slow wave following them. Also, there is no spread of this activity to other areas of the brain. Sleep records may help doctors to tell the difference between breach rhythm and epileptiform activity, although breach rhythms could affect both awake and sleep patterns.
Epileptiform abnormalities, which are irregularities often seen on an EEG in people with epilepsy, become more prominent during NREM (Non-Rapid Eye Movement) sleep and less prominent during REM (Rapid Eye Movement) sleep. If breach rhythm is mostly made up of increased underlying rhythms, it will fade or disappear during drowsiness and sleep. A mid-temporal, alpha-like rhythm mixed with the breach rhythm might linger into drowsiness and light NREM sleep. The patient could be asked to move the opposite limb to test a mu rhythm (a specific type of brain wave pattern) within the breach rhythm. If the rhythm fades, it suggests that it’s a normal pattern; however, if it doesn’t, it does not rule out the presence of a normal rhythm.
Special care should be taken with the EEG filters, as the ones used to reduce high frequencies might filter out the higher frequencies of breach rhythm. The remainder could look like spikes or sharp waves. Muscle artifacts, which are another type of brain wave pattern often caused by muscle activity, can usually be easily identified by their much higher frequency component, provided an appropriate high-frequency filter is chosen. Therefore, removing muscle activity will reduce the signals and may confuse it for abnormalities within the breach rhythm.
Treatment Options for Breach Rhythm
Breach rhythm is a minor variation in brain wave activity that usually doesn’t require any treatment. But if brain waves (measured by EEG or electroencephalogram) start to show more prominent slow waves or changes in pattern over time, it may indicate a growing problem under the region of the skull.
It’s equally essential not to overlook any signs of epilepsy, which might appear with a breach rhythm. Slow waves, especially in the delta range (a certain frequency of brain waves), signify actual underlying health issues.
Most experts urge a careful approach when interpreting these brain wave readings, as mistakenly seeing a problem where there isn’t one can be more detrimental than missing a minor issue. If there’s uncertainty, a brain CT scan or an MRI may help establish if any distinct brain abnormalities are causing seizures.
What else can Breach Rhythm be?
It’s necessary to tell the difference between a breach rhythm and discharges that occur between seizures, identified as “interictal epileptiform discharges.” You can distinguish these by closely observing the background activity. Interictal discharges are usually more complicated, containing a slow wave, and their form doesn’t resemble the ordinary background activity.
Interictal epileptiform discharges can include:
- Quick, sudden activity
- Beta frequency activity
- Electromyographic (EMG) activity, a type of muscle-based interference
The breach effect, on the other hand, usually shows a clearly boundary-defined area of elevated amplitude. This sudden fast activity appears in bursts, going back to the asymmetric baseline in the intervals.
You can set apart the breach rhythm from beta activity by noting its distribution. While normal beta activity is seen on both sides, it can fluctuate in terms of distribution.
EMG interferences appear where muscles overlay, mostly in the front and sides of the head. You can tell EMG artifacts apart by their inconsistent appearances and significantly higher components.
What to expect with Breach Rhythm
The term “breach rhythm” refers to a variant of your normal heart rhythm. But don’t worry, it’s usually nothing to be concerned about. In fact, the long-term outlook for people with breach rhythm is excellent. This means that having a breach rhythm isn’t likely to cause any significant or harmful health problems in the future.
Possible Complications When Diagnosed with Breach Rhythm
Not correctly identifying the difference between a breach rhythm and epileptiform irregularities can lead to misunderstandings and issues. Because of their similar features, the sharply-defined shape of a breach rhythm could be incorrectly thought to be an epileptiform irregularity. This could cause a person to wrongly be diagnosed with epilepsy and given unnecessary epilepsy medication. On the other hand, if epileptiform irregularities occur in the same area as a breach rhythm, they might be missed leading to undiagnosed cases. So, it’s really important to correctly and accurately interpret these rhythms because it has a big impact on patient care.
Understanding the Difference:
- Misunderstanding can lead to incorrect diagnosis and unnecessary treatment.
- Epileptiform irregularities could be undiagnosed if occurring in areas of breach rhythm.
- Accurate interpretation is crucial for appropriate patient care.
Preventing Breach Rhythm
Understanding the different patterns in an EEG (or brain wave test) is very important to correctly diagnose epilepsy and avoid medical mistakes. An EEG test can show both harmless (benign) and harmful (pathological) signs, so it’s crucial to know the difference to make an accurate assessment. Misunderstanding these patterns can lead to wrong diagnoses and may harm the patient’s health. So, learning to identify these signs accurately is vital in preventing negative health outcomes.
