the term nonconvulsive status epilepticus ( ncse ) is defined as  a range of conditions in which electrographic seizure activity is prolonged and results in nonconvulsive clinical symptoms  , .
the clinical features of ncse may be subtle and diverse , and confirmation relies on the electroencephalogram ( eeg ) .
several approaches to establishing criteria for ncse in adults have been published ( table  1 ) , , , and some clinical states may lie along an ictal  interictal continuum .
periodic discharges are often regarded on the interictal end of the spectrum , but when accompanied by clinical features including impaired vigilance and when signs resolve proximate to treatment , then this lends evidence to the ictal nature of periodic discharges along this spectrum .
periodic lateralized epileptiform discharges ( pleds ) , in particular , have sparked controversy with regard to being part of the ictal vs. interictal spectrum .
periodic lateralized epileptiform discharges can occur in the temporal vicinity of an overt seizure , thus reflecting an ictal 
interictal continuum phenomenon that can continue for weeks ( chronic pleds ) in conscious patients with retained alpha or basic rhythm .
however , when they occur in a patient with altered level of consciousness , some authors regard it as ictal , , , , , , , , . since changes in mental status are common in epileptic encephalopathies and developmental delay such as in patients with cerebral palsy , it can be difficult or impossible to determine whether they are in status epilepticus , unless there is a discernible clinical improvement with treatment .
we report the case of a patient with chronic epilepsy and cerebral palsy ( cp ) who presented with deterioration from an already impaired baseline .
although the eeg revealed slow pleds which are not typical of ncse , the patient showed a good clinical and eeg response to benzodiazepines with pled regression .
this 49-year - old man with cerebral palsy , mental retardation , and epilepsy residing in a long - term care facility for the prior 13  years had been awake , noncommunicative , but responsive to auditory and visual stimuli .
he was treated with phenytoin and levetiracetam and had yearly breakthrough seizures over the prior 10  years .
he had recently developed fever and dyspnea with a drop in oxygen saturation and was suspected of having aspiration pneumonia complicated by sepsis .
he was given intravenous antibiotics , fluids , and supplemental oxygen and was transferred to our facility . following a mild generalized tonic 
clonic seizure , his examination remained persistently unchanged but he was now unresponsive to auditory , visual , and noxious stimuli , with a fluctuating level of alertness .
plasma phenytoin level was low at 34.8  mol / l ( normal : 4080  mol / l ) .
1 ) showed intrusions of excess slow left - sided periodic lateralized epileptiform discharges ( pleds ) on a background of normal alpha pattern .
administration of 1  mg of iv lorazepam resulted in resolution of the  slow  pleds ( fig .  2 ) and
improvement in the patient 's neurological status , which now became responsive to auditory , noxious , and visual stimuli that occurred in a matter of 15  min after administration of lorazepam . by the next morning , his condition had greatly improved and he was near his baseline status .
he received additional intravenous loading doses of phenytoin and levetiracetam on the same day , and his maintenance doses were adjusted .
brain ct showed a large central meningioma as well as a small posterior fossa meningioma ( fig . 
review of his old brain ct films ( done seven years ago ) showed no such lesions .
because of his poor quality of life and the risks involved , neurosurgery was not considered an option , and the patient was managed medically with antiepileptic medication .
4 ) , and the patient was discharged to a long - term care facility for further care .
this patient with chronic epilepsy and cerebral palsy ( cp ) showed deterioration from a baseline that was already impaired , a finding described in ncse in those with developmental disability , .
the eeg findings were not typical of ncse in that slow pleds lie in the gray zone along the ictal  interictal continuum .
cerebral palsy is a complex , heterogeneous lifelong condition with significant disability and long - term challenges that persist into adult life .
epilepsy is reported in 35% to over 60% of patients with cp ,   and is more frequent in patients with more severe disability
. sixteen percent of children with cp and epilepsy may develop nonconvulsive and/or convulsive status epilepticus .
brain tumors , particularly primary ones , are associated more frequently with both convulsive and nonconvulsive status epilepticus , .
electroencephalographic changes in mass lesions reflect irritability around the penumbra of the lesion , in this case , on the left .
one can speculate that the focal structural lesion in the setting of chronic diffuse brain dysfunction , along with intercurrent infection and low aed levels , represented the multiple risk factors seen in the recurrence of seizures and appearance of ncse , . periodic lateralized epileptiform discharges ( fig . 
1 ) consist of periodic spike - and - slow wave or sharp - and - slow wave complexes , typically with a frequency of 12  hz . in our patient , the frequency was ~  0.5  hz .
periodic lateralized epileptiform discharges occur in a variety of conditions such as strokes , tumors , and infections ; these together comprise around 50% of the underlying etiologies .
slow growing extraaxial tumors such as meningiomas usually produce little eeg disturbance unless they compress and displace brain tissue or cause hydrocephalus such as in our case .
periodic lateralized epileptiform discharges are reported to support a diagnosis of ncse if they meet certain conditions , in particular , good proximate clinical and eeg response to benzodiazepines with pled regression   ( table  1 ) .
when eeg and clinical regression are not clear , spect or pet scanning can guide the clinician in the possible ictal ( versus interictal ) nature of the periodic discharges , .
there are diagnostic and management challenges in patients with long - term disability whose cognitive and neurological baselines are impaired and not always known to the clinical caregivers .
additionally , a diagnosis of ncse may be difficult to make when this baseline is unknown and when the eeg findings represent a pattern that lies along the ictal  interictal continuum .
electroencephalogram can establish where along this continuum the patient resides , following which treatment that balances the risk  benefit needs of the patient , and the needs of chronic caregivers , can then be provided and monitored so as to offer the patient the optimal chance for regaining lost function with minimal risk .
 the presence of cerebral palsy and that of slow growing brain tumors are risk factors for convulsive and nonconvulsive status epilepticus . 
 nonconvulsive status epilepticus ( ncse ) needs electroencephalographic ( eeg ) monitoring to be confirmed as it may be clinically subtle . 
 furthermore , it may present with a variety of ictal eeg morphologies . 
 we report a case of a patient with cerebral palsy and a large central meningioma . 
 electroencephalogram showed a slow pattern of periodic lateralized epileptiform discharges ( pleds ) ( a pattern considered as being situated in the ictal  
 interictal continuum ) on an alpha background . 
 the patient was treated for ncse successfully with benzodiazepines followed by up - titration of his antiepileptic drug doses . 