During medical tests like an electrocardiogram (ECG) or electroencephalogram (EEG), you may see “somatic artifact” on your report. This term refers to interference that can appear on diagnostic readings. Understanding somatic artifacts helps clarify why some test results might look unusual.
What is a Somatic Artifact?
A somatic artifact represents an unwanted signal or distortion in a medical measurement. The term “somatic” relates to the body, specifically voluntary movements and skeletal muscles. An “artifact” signifies an error or misleading detail in data collection. Therefore, a somatic artifact is a disruption in a medical test’s recording that originates from the patient’s physical activity or muscle electrical impulses. This interference is not indicative of an underlying medical condition; rather, it is extraneous “noise” that can obscure the genuine biological signals the test aims to capture.
Common Causes of Somatic Artifacts
Several common physical actions can generate somatic artifacts during medical tests. Patient movement, whether voluntary (like shifting position) or involuntary (like a sudden cough or talking), creates electrical signals in the muscles. These muscle potentials can be picked up by sensitive recording equipment, mixing with the intended physiological data. Muscle tension resulting from anxiety, discomfort, or even subtle tremors can also produce electrical activity that interferes with the test.
Shivering due to cold temperatures is a frequent cause of these artifacts, as the rapid muscle contractions generate significant electrical noise. Other bodily functions, such as hiccups, or neurological tremors often associated with conditions like Parkinson’s disease, also produce muscle activity that the sensors detect. Even deep or irregular breathing can cause slight movements of the chest wall, contributing to signal distortion. These actions introduce their own electrical signatures, which the diagnostic machinery then records alongside the actual electrical activity from organs like the heart or brain.
Impact on Diagnostic Tests
The presence of somatic artifacts can significantly impact the interpretation of diagnostic tests by obscuring or distorting the true biological signals. This “noise” can make it challenging for healthcare professionals to accurately assess a patient’s condition. For example, in an electrocardiogram (ECG), which measures the heart’s electrical activity, muscle artifacts can mimic or completely hide genuine heart rhythm abnormalities. This interference can lead to an unclear tracing, making it difficult for a cardiologist to reliably diagnose conditions such as arrhythmias or ischemia.
Similarly, an electroencephalogram (EEG) is highly susceptible to muscle artifacts, particularly from facial and scalp muscles. These artifacts can appear as sharp spikes or high-frequency waves, potentially masking abnormal brain activity associated with neurological disorders like epilepsy. When artifacts are extensive, the test results may become inconclusive, necessitating a repeat of the procedure. This can delay diagnosis and potentially prolong the patient’s discomfort or anxiety.
Managing and Preventing Somatic Artifacts
Medical professionals employ several strategies to minimize and prevent somatic artifacts, ensuring clearer diagnostic readings. Technicians often begin by ensuring the patient is in a comfortable and warm environment, as cold can induce shivering. They provide clear instructions, asking the patient to lie still, relax, and avoid talking or moving during the recording period. This helps to reduce voluntary muscle activity and tension.
Proper skin preparation before electrode placement is also a contributing factor to signal quality. This often involves gently abrading the skin or using an alcohol wipe to remove dead skin cells and oils, which can impede electrical conductivity. Accurate and secure placement of electrodes or sensors on the patient’s skin is also performed to ensure good contact and reduce the chance of signal interference from loose connections. These proactive measures help to improve the clarity and reliability of the test results.