(Kiosk 3) Baclofen as an Adjunct Therapy to Improve Motor Control in Post-hypoxic Cortical Myoclonus: A Case Report

Case Diagnosis: 22-year old African American female with cortical myoclonus after hypoxic brain injury

Case Description or Program Description: Patient was admitted to acute rehabilitation after acute congestive heart failure. She experienced cardiac arrest with pulseless electrical activity with return of spontaneous circulation after 30 minutes. Shortly thereafter, she developed full body trembling without epileptiform activity on EEG so was diagnosed with post-hypoxic myoclonus. On rehab admission, regimen was Clonazepam 1.5mg TID and Valproate 500mg TID. At rest, patient had mild diffuse tremulousness which amplified with initiation of motor movements. She was deconditioned with diffuse weakness, minimally able to perform simple commands and unable to perform fine motor movements. She required total assistance for activities of daily living (ADLs) and had vocal tremulousness limiting communication. Participation with therapies was hampered by intention myoclonus. Given lack of EEG findings and ineffectiveness, the plan was to wean Valproate and start Baclofen as an adjunct. Changes were tolerated well. She was discharged on Clonazepam 2mg TID and Baclofen 10mg TID. Patient showed clinical improvement of intention myoclonus, ADLs (minimal-moderate assistance), and improved vocal control/phonation. Patient had sufficient gross and fine motor control to operate a power wheelchair. After a total hospital course of 6 months, she was discharged home.

Setting: Acute Inpatient rehabilitation

Assessment/Results: Cortical myoclonus secondary to hypoxic brain injury was managed with Baclofen and Clonazepam, resulting in improved motor control, independence and functionality with ADLs, and vocal control.

Discussion (relevance): Treatment of cortical myoclonus is limited by patient sparsity with minimal evidence-based guidelines dictating best practice. Conventionally, anti-epileptics are utilized as first line agents with mixed efficacy. Existing research theorizes a potential role for GABA-ergic agents. Increased cortical inhibition is believed to limit excitation resulting in improved spontaneous and intention-based jerking. Clonazepam’s efficacy is theorized to increase inhibitory (GABA-ergic) transmission. Baclofen, a known GABA-B augmenting agent, may provide an additional treatment option for patients with cortical myoclonus not correlated to epileptiform activity.

Conclusions: GABA-ergic agents like Baclofen, may have a significant role in symptom management of cortical myoclonus. Further research is required to assess efficacy and consideration for more routine use in this population.