Hanging-induced burst suppression pattern in EEG.

Lethal suspension (hanging) is one of the most common methods of attempting suicide. Spinal fractures, cognitive and motor deficits as well as epileptic seizures can be detected after unsuccessful hanging attempts. Introduced here is the case of a 25-year-old man exemplifying the clinical observations stated hereafter, who was conveyed to our emergency room after having survived attempted suicide by hanging, with his post-anoxic burst-suppression electroencephalography (BS-EEG) pattern and clinical diagnoses in the post-comatose stage. The patient's state of consciousness was gradually improved over a period of time. His neuropsychiatric assessment proved that memory deficit, a slight lack of attention and minor executive dysfunction was observed a month after the patient was discharged. Although the BS-EEG pattern indicates severe brain dysfunction, it is a poor prognostic factor; rarely, patients survive with minor cognitive deficits and can perform their normal daily activities.

INTRODUCTION

Several studies have been conducted citing the neuropsychological consequences regarding non-lethal hanging of adults.[1] The primary findings are described as memory deficits and anterograde-retrograde amnesia. However, isolated memory disturbances can occur, though rarely, without other cognitive dysfunctions accompanying them. Other cognitive deficits such as visuospatial impairment, expressive language deficits, behavior and personality changes are usually associated with memory disturbance.[2] In post-anoxic states, various electroencephalography (EEG) changes are possible. Post-anoxic burst-suppression electroencephalography (BS-EEG) implies a poor prognosis.[3] It is rare to encounter case reports in medical literature about cognitive improvement in patients with BS-EEG.[4]

We have documented our evaluation of a patient's cognitive recovery following BS-EEG after his attempted suicide via lethal suspension.

CASE REPORT

The patient was discovered by his family in a potentially lethal suspension by ligature. The duration of hanging was approximated at 15 minutes. In the emergency unit, the patient was admitted with a glasgow coma scale (GCS) score of 3, his brainstem reflexes were absent, and he exhibited contracted, non-reactive pupils. There was a hemorrhagic strangulation band around the patient's neck. Myoclonic jerks were observed while in the emergency unit. His arterial O2saturation was measured at 75%. Endotracheal intubation was performed and he was transferred to the intensive care unit. No sedatives or curare medications were used. The computed tomography (CT) showed diffuse cerebral edema. EEG electrodes were placed according to the International 10-20 system. The burst suppression pattern (BS) was observed during the first 3 hours of EEG [Figure 1a]. Intravenous valproic acid (2 × 400 mg per/day) was used and myoclonic jerks ceased within 2 days. The BS pattern was diagnosed as previously described: “High-voltage bursts of slow waves with sharp or spiked transients occuring against a depressed background”.[5] BS-EEG continued in the second EEG recording, in the first 24 hours [Figure 1b]. In the third EEG recording on day 6, generalized slow wave activities were discerned [Figure 2a]. The GCS score was 5 and brainstem reflexes were present. Temporal relationship between consciousness and EEG findings are demonstrated in [Table 1]. On day 10, the patient was responding to painful stimuli with flexor motor response in his extremities and he was extubated on day 13. In the last EEG recording [Figure 2b], generalized low amplitude alpha and fast beta activities were revealed and the GCS score increased to 15. The repeated CT was recorded as normal. After 1 month, the patient was transferred to the rehabilitation unit.

Figure 1a

Generalized periodic sharp wave paroxysms and background activity was highly suppressed [3 hours after injury]

Figure 1b

Number of paroxysms increased and suppression continued [24 hours after injury]

Figure 2a

Widespread high-amplitude slow wave activity in the frontal region [6 days after injury]

Table 1

Temporal relationship between consciousness and EEG findings

Figure 2b

Fast rhythm activity in the frontal region and alpha rhythm in the parieto-occipital region during the resting state nearly similar to the physiological limits [13 days after injury]

Neuropsychological test battery

Neuropsychological evaluation was applied for the first month after hospitalization. A total of 10 tests were selected to cover major cognitive domains: Wechsler Memory Scale-III [WMS-III,[6] the Verbal Fluency,[7] Dual Similarities,[6] Clock Drawing Test,[8] Luria Drawings,[9] Benton Face Recognition Test,[10] Famous Faces Test,[11] Benton Judgment of Line Orientation Test,[12] Hooper Visual Organization Test,[13] Boston Naming Test.[14] Test scores are presented in Table 2. The outstanding findings were memory deficits, deterioration in the attention. Also, mild dysfunction was detected in some executive functions like working memory, planning, cognitive flexibility, and inhibitory control.

Table 2

Neuropsychological tests results

DISCUSSION

Hanging is one of the most commonly used methods of suicide among both men and women. The impact of lethal suspension on cognitive functioning is dependent on the length of asphyxiation time. Enhancing initial diagnoses with EEG and cognitive tests can provide important information in determining the prognosis. Post-anoxic BS-EEG implies a poor prognosis as shown in previous related studies.[3] Wijdicks et al.[15] reported a repeat EEG in nine patients with BS-EEG on the day of resuscitation. Persisting BS-EEG was seen in six patients and transition to alpha coma pattern was seen in three patients. Thâmke et al.[3] reported 24 consecutive patients who developed BS-EEG within 24 hours after cardiopulmonary resuscitation. In this progression, with only one exception, BS-EEG was followed by another EEG pattern within 1 day, mainly a reactive α EEG, isoelectric EEG, generalized continuous epileptiform discharges and θ EEG. In our patient, BS-EEG continued for 24 hours, followed by different wave patterns on the EEG, which were associated with generalized slow wave patterns and low amplitude alpha activity. Parallel to the clinical improvement, the EEG of our patient underwent a dramatic improvement and BS-EEG disappeared completely. Post-anoxic BS-EEG and subsequently evolving EEG patterns most probably reflect different forms of dysfunction of severely damaged cortical neurons. BS-EEG mostly indicate poor prognosis. However, our patient showed near-complete recovery. Earlier studies have demonstrated that patients with myoclonic jerks accompanying post-anoxic BS-EEG exhibit a poor prognosis and anticonvulsant drugs are usually ineffective. Our patient showed good prognosis in contrast to the expected trend. Myoclonic jerks stopped anticonvulsant treatment. Some anesthetic medications like propofol may cause a BS pattern in EEG.[1617] Medication was not the cause of BS pattern in our case, as the EEG was performed prior to the use of any medication.

The cognitive recovery patterns following anoxic injury have been documented by Caine and Watson. They revealed that amnesia is not detected in all cases of hypoxic-ischemic injury; it rarely exists as the only deficit.[2] Zabel et al. said that amnesia could be due to hippocampal damage.[1] Brain imaging methods as CT, magnetic resonance imaging (MRI), single photon emission tomography (SPECT) is useful in showing brain damage.

CONCLUSION

In our patient, CT showed widespread brain edema. After a month, neuropsychological test battery identified mild memory deficits with an impairment of attention. BS pattern following lethal suspension has been reported for the first time. Our case is highly promising as it shows a good prognosis although burst-suppression pattern was perceived in EEG.