EPP055
Utilizing Evoked Response Potentials to predict clinical outcomes to Methylphenidate in children with Attention Deficit Hyperactivity Disorder
M. Mathew 1,*, B. N. Patra 1, R. Sagar 1, R. Verma 1, R. Bhargava 1, S. Kaur 2
1Psychiatry, 2Physiology, All India Institute of Medical Sciences, New Delhi, India
Introduction: Attention Deficit/ Hyperactivity disorder is a neurodevelopmental disorder characterised by persistent pattern of hyperactivity, impaired attention and poor organization. ADHD is associated with multiple neurophysiological deficits leading to impairment in sustaining attention, reward processing and regulation of behavior. There is marked intra- individual variation in presentation due to the diagnostic, developmental and neurobiological heterogeneity which can make treatment challenging. Identifying biological predictors of treatment response becomes imperative to develop personalized regimens for the various subsets. Evoked response potentials (ERP) allow the assessment of sensory and cognitive processes and can be potentially useful.
Objectives: This study endeavors to explore the potential Evoked response potentials in predicting medication response.
Methods: Longitudinal observational study, with sample size of 30 male cases of ADHD aged between 8-16 years who were planned to be started on Methylphenidate by their treating psychiatrist. Informed consent from parents and assent from the study participants were taken. Severity of ADHD was assessed using Conner’s parent rating scale (CPRS). Prior to starting treatment, a 32 channel electroencephalograph (EEG) recording was taken while the participants were performing an auditory oddball task. Amplitude and latencies of P300 and N200 (evoked potentials) were extracted from the EEG data for 3 central channels (Cz, Oz, Pz) . Participants were divided into good and poor responders following 4 weeks of treatment and baseline ERP data was compared between both groups.
Results: P300 amplitude and latency across Auditory Oddball task did not reveal significant differences between Good and Poor Responders except P300 latency of the target stimuli over Cz channel location, participants who responded better to medication had significantly lesser latency as compared to the other group. P300 amplitude at Cz and Pz of non target stimuli correlated negatively with improvement in hyperactivity and total symptom score on CPRS- lower P300 amplitude predicted better improvement (p=0.02, 0.04 at Cz and Pz respectively).
N200 of non target stimuli had a significantly smaller amplitude in good responders as compared to poor responders in our study. A significant correlation was found between the amplitude and improvement in inattention score (rho 0.45, p-0.01) on Cz location. N200 latency was also found to be significantly longer in good responders and correlated with improvement in CPRS scores at all three channel locations.
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Conclusions: There are differences in Evoked response potentials in Cz and Pz channels between good and poor responders. This underscores the importance of further research on neurophysiological markers as a predictive biomarker to various treatment modalities for ADHD.
Disclosure of Interest: None Declared