Table 1.

Effectiveness of different therapies in NKH.

Therapy	Clinical Outcome	Patients Group	Authors
Sodium benzoate	Reduction in plasma glycine level to ≤300 μmol/L, increase in alertness, decrease in seizures or a decreased number of anticonvulsants.	22/26 with severe neonatal NKH, 6/6 with attenuated neonatal NKH, 2/3 with severe infantile NKH, 1/3 with attenuated infantile NKH.	Hennermann et al. [5]
Dextromethorphan	Increase in alertness, a decrease in seizures or a decreased number of anticonvulsants.	8/13 with severe neonatal NKH, 2/2 with attenuated neonatal NKH, 1/2 patients with severe infantile form, and 3/3 patients with attenuated infantile NKH.	Hennermann et al. [5]
Sodium benzoate and dextromethorphan	Improvement in apnea and initially better seizure control.	Patient with neonatal NKH.	Shin et al. [31]
	Amelioration of encephalopathic symptoms, increased alertness and decreased seizures (temporary) and (temporary) reduction in CSF glycine levels.	Patient with neonatal NKH.	Ichikawa et al. [22]
	Reduction in seizure frequency and an improvement of alertness, developmental progress (only patients with attenuated NKH).	9 patients with severe NKH and 1 patient with attenuated NKH.	Bayrak et al. [20]
	Improvement in neurodevelopmental outcome and seizure control.	4 patients with attenuated NKH.	Bjoraker et al. [7]
	Reduction in myoclonic seizures.	Patient with attenuated NKH.	Brunel-Guitton et al. [32]
Sodium benzoate and ketamine	Benign neonatal course with no hypotonia and apnea.	Patient with severe NKH.	Korman et al. [8]
	Improvement in the frequency of myoclonic jerks and hypotonia.	1 of 2 patients with severe NKH.	Poothrikovil et al. [25]
	Improvement in hypotonia, apnea and respiration abnormalities, the proper level of alertness and attainment of developmental milestones.	2 patients with neonatal NKH.	Boneh et al. [29]
Perampanel	Reduction of 50% of epileptic spasms.	Patient with severe NKH.	Daida et al. [17]
Ketogenic diet	Reduction of over 50% of seizures.	3 patients with severe NKH with early myoclonic encephalopathy.	Cusmai et al. [16]
	Reduction in seizure frequency and antiepileptic drugs, spasticity reduction.	Patient with severe NKH.	Kava et al. [26]
	Lowering glycine levels, improvement of tonic spasms and tonic-clonic seizure control and complete resolution of tonic-clonic seizures.	2 patients with severe NKH.	Shbarou et al. [3]
	Resolution of super-refractory status epilepticus (SRSE).	Patient with severe NKH.	Appavu et al. [42]
Vagal nerve stimulation	Reduction of >75% of myoclonic and tonic seizure frequency, reduction in tonic seizures (of 90%), withdrawal or reduction of antiepileptic drugs from 6 to 3.	2 patients with severe NKH.	Tsao et al. [44]
	Reduction in seizure frequency of more than 90%, dose reduction of AEDs.	Patient with neonatal NKH.	Grioni et al. [43]