The Thompson score is a clinical tool used by medical professionals to evaluate a newborn’s neurological condition, particularly when there is concern for brain injury from oxygen deprivation during birth, known as Hypoxic-Ischemic Encephalopathy (HIE). The score provides a standardized method for assessing a baby’s brain function shortly after delivery, helping to quantify the extent of neurological dysfunction.
This evaluation establishes a baseline neurological status, allowing healthcare providers to track changes over time. The score is not a diagnosis on its own but is a component of a comprehensive neonatal assessment. It is often used alongside other measures, such as the Apgar score, to build a complete picture of the newborn’s health.
What the Thompson Score Assesses
The Thompson score is a comprehensive evaluation based on nine neurological and physiological signs observed to create a picture of the infant’s central nervous system function. The assessment includes the level of consciousness, observing if the baby is alert, lethargic, or comatose. An infant’s posture is also examined, contrasting a normal, well-flexed position with limp or unusually stiff postures.
Muscle tone is another parameter, assessing for firmness, hypotonia (flaccidity), or hypertonia (rigidity). Several reflexes are tested, including the Moro (startle) reflex, the grasp reflex, and the suck reflex. The absence or weakness of these reflexes can indicate neurological impairment.
The assessment also includes brainstem functions. The infant’s respiratory pattern is monitored for abnormalities like rapid breathing or apnea (temporary cessation of breathing). The presence of seizures is a direct sign of abnormal brain activity, and the fontanelle (soft spot) is checked for bulging, which can indicate increased pressure within the skull.
The Scoring System Explained
Each of the nine parameters is assigned a value ranging from 0 to 2, and in some cases 3, to quantify its status. A score of 0 represents a normal finding, indicating the infant’s response is as expected. This system allows for a graded assessment rather than a simple present-or-absent judgment.
A score of 1 is assigned to a mildly or moderately abnormal parameter, such as somewhat reduced muscle tone. A score of 2 indicates a severely abnormal or absent finding, like a completely flaccid infant. For some parameters like respiration, the scale can extend to 3 for the most severe abnormalities, such as requiring mechanical ventilation.
The individual scores for all nine categories are summed to produce a total score. The lowest possible score is 0, signifying a normal neurological exam, while the maximum is 22, indicating severe encephalopathy. This cumulative score provides a single, quantitative measure of the infant’s overall neurological state.
Interpreting the Results
The total Thompson score, which ranges from 0 to 22, is used to classify the severity of Hypoxic-Ischemic Encephalopathy into three distinct categories. This categorization helps medical teams understand the degree of neurological impairment and communicate the infant’s status in a standardized way.
A total score between 1 and 10 is classified as mild encephalopathy. Infants in this category show subtle signs of neurological dysfunction but are in a more stable condition. A score in the range of 11 to 14 indicates moderate encephalopathy, with more definite neurological abnormalities and a higher risk of complications.
A score of 15 or higher signifies severe encephalopathy. This category represents the most serious level of brain dysfunction, where infants often exhibit abnormalities such as unresponsiveness, absent reflexes, and persistent seizures. A higher score is strongly correlated with a greater likelihood of adverse outcomes.
Clinical Significance and Next Steps
The Thompson score has prognostic value, as the initial score and its progression can help predict long-term neurodevelopmental outcomes. A consistently high score is associated with an increased risk of challenges like cerebral palsy or developmental delays, allowing clinicians to inform parents and plan for follow-up care.
The score also directly influences immediate treatment decisions in the neonatal intensive care unit (NICU). A primary use of the score is to identify candidates for therapeutic hypothermia, also known as cooling therapy. This treatment involves lowering the infant’s body temperature for 72 hours to slow metabolic processes in the brain, which can reduce injury after a hypoxic-ischemic event.
Clinical guidelines often use a specific Thompson score as a criterion for initiating this time-sensitive intervention. For example, a score greater than 7 may be used to select infants who could benefit from this treatment. The score helps ensure that eligible infants receive cooling therapy promptly, which is known to improve survival and reduce the risk of long-term disability.