「Study on the Correlation between ADHD and Myoclonus」ADHD와 간대성근경련과의 상관관계 연구 - Tae E. Ha
ABSTRACT ●Background: This study originated from the coincidental discovery of involuntary muscle jerks, suspected to be pediatric myoclonus, in some children with ADHD through the 「ADHD Pulse Test (APT」). This research aimed to investigate the association between such myoclonus and ADHD. ●Objectives: The primary objectives of this study were to confirm the presence of myoclonus, a neurologically induced clinical sign, in children with ADHD and to validate the APT, designed as a diagnostic method, as an initial evaluation tool. ●Methods: Fifty school-aged children (46 boys, 4 girls) aged 5–15 years, residing in the same regional environment in Illinois, participated in the study. Group A comprised 25 children diagnosed with ADHD by a child psychiatrist, while Group B consisted of 25 children whose parents suspected ADHD. The APT was administered to both groups to ascertain the presence of myoclonus, and significant differences in symptom severity between Group A and Group B were analyzed. ●Results: A statistically significant difference was observed in diagnostic outcomes related to myoclonus confirmation in children with ADHD. Analysis of severity based on myoclonus confirmation revealed a 44% difference between the proportion of severe cases and the combined proportion of moderate and mild cases in Group A, and a 36% difference in Group B, indicating a statistically significant distinction. Therefore, myoclonus was found to act as a fundamental pathological variable in ADHD, and the APT was evaluated for its validity as a method for observing myoclonus, a clinical sign of ADHD. ●Conclusions: The findings of this study support the significance of myoclonus in understanding specific neurological conditions in children with ADHD within a clinical setting. Furthermore, this research suggests the potential of APT as an initial clinical examination tool capable of identifying myoclonus, a biological marker. This is highly significant as it allows for the prediction of ADHD presence and symptom severity, thereby contributing to the improvement of existing ADHD diagnostic and evaluation methods.
●Keywords: Myoclonus, Attention Deficit Hyperactivity Disorder (ADHD)
IV. DISCUSSION
ADHD is a common neuropsychiatric disorder in children and adolescents, primarily characterized by inattention, hyperactivity, and impulsivity. Despite ADHD being known to arise from multifactorial causation, even the authors of the DSM-5-TR have not yet found clear biological markers for its diagnosis.Consequently, current diagnoses rely solely on the ADHD Rating Scale (ADHD-RS) and clinical observation. If these methods overly focus on non-specific symptoms, the diagnostic scope for ADHD can be unnecessarily broadened. This can lead to the inclusion of children who do not actually have ADHD within the diagnostic range,42 or result in overdiagnosis and overtreatment for children with mild symptoms,43 potentially causing unnecessary drug dependence or side effects. To address these issues, there's an urgent need to introduce APT as an initial evaluation tool capable of replacing neurological imaging tests. Additionally, research into myoclonus, which appears as a clinical sign in various neurological disorders, is warranted.This study yielded three main results: First, an analysis of myoclonus confirmation in 50 children with ADHD (Groups A and B) revealed that 24 children (48%) were confirmed, while 26 children (52%) were unconfirmed. Specifically, 17 out of 25 children (68%) in Group A, diagnosed with ADHD by a specialist, were confirmed with myoclonus. In contrast, only 7 out of 25 children (28%) in Group B, whose ADHD was suspected by their parents, were confirmed. This suggests that myoclonus confirmation via specialist diagnosis and APT shows a higher concordance rate than ADHD diagnoses based on parents' subjective judgment. Therefore, it's crucial to identify the presence of myoclonus as a specific biological marker of neuropsychiatric disorders for a clear ADHD diagnosis. If APT, which determines myoclonus confirmation, is introduced, it is expected to effectively prevent overdiagnosis errors, one of the potential issues arising from self-report measures38 based on parents' subjective judgment.31 Second, we analyzed the differences in ADHD symptom severity based on the presence of myoclonus, which is a fundamental cause of ADHD. Group A showed a 72% severe symptom ratio, with a combined moderate and mild symptom ratio of 28%, indicating a 44% difference. In contrast, Group B had a 32% severe symptom ratio, and a combined moderate and mild symptom ratio of 68%, showing a 36% difference. Notably, Group A had a 40% higher severe symptom ratio compared to Group B. Importantly, all 24 children confirmed with myoclonus exhibited high-severity symptoms, classified as severe. This suggests that myoclonus, as a fundamental pathological variable in ADHD, may exert a direct synergistic effect, intensifying symptoms, or alternatively, myoclonus could serve as an indicator to determine the presence of a disorder or its symptom severity. Therefore, if APT can confirm myoclonus to predict the presence of ADHD and the severity of its symptoms, it could prevent potential misdiagnoses. For example, behavioral patterns stemming from temperamental traits, emotional regulation issues, or sensory processing problems (e.g., typical behaviors observed in children relatively young for their grade level)44 are not considered abnormal in children without myoclonus, but they could be misdiagnosed as severe ADHD. Furthermore, there's a higher likelihood of misdiagnosing ADHD when differentiating it from other conditions that might present similar symptoms, such as personality disorders, tic disorders, learning disabilities, or sensory processing disorders.40 Such misdiagnoses can lead to ineffective treatment, unnecessary procedures, and even harmful consequences. Third, the characteristics and expected benefits of APT have been confirmed through clinical experience. Myoclonus was identified as a crucial indicator for confirming the presence of ADHD and determining the severity of its symptoms. This demonstrates the urgent need to introduce APT as an initial clinical examination tool capable of assessing myoclonus. Utilizing APT can address the limitations of the ADHD Rating Scale (ADHD-RS), thereby preventing overdiagnosis and misdiagnosis, which are current medical and social points of contention. This is ultimately expected to contribute to reducing unnecessary prescriptions and treatments, alleviating the financial and psychological burden on parents.
However, considering that myoclonus was observed only in some children exhibiting severe symptoms in this study, it suggests that these are not universal findings. Therefore, additional objective evidence is required to definitively consider myoclonus as a specific biological marker for ADHD, a neuropsychiatric disorder, which limits its immediate application in ADHD diagnosis. Consequently, we anticipate that future research will provide further validation by identifying correlated abnormal brainwave patterns between ADHD and myoclonus through objective electroencephalography (EEG).
