Elsevier

Pediatric Neurology

Volume 24, Issue 2, February 2001, Pages 129-134
Pediatric Neurology

Original article
Long-term sleep disturbances in adolescents after minor head injury

https://doi.org/10.1016/S0887-8994(00)00254-XGet rights and content

Abstract

It has been demonstrated that patients in the acute phase after minor head injury (MHI) complain of sleep disturbances. The purpose of the present study was to characterize the long-term effects of MHI on sleep in adolescents. Nineteen adolescents who had suffered MHI 3 years before the study and had complained of sleep disturbances completed a sleep questionnaire and were investigated in the sleep laboratory by whole-night polysomnographic recordings and were actigraphically monitored for 5 days at home. Questionnaire results revealed severe complaints regarding sleep behavior. Polysomnographic recordings revealed that in comparison with controls, MHI was associated with lower sleep efficiency (79.8 ± [9.8]% vs 87.7 ± [6.8]%; P < 0.005), with more wake time (10.6 ± [9.0]% vs 3.4 ± [4.4]%; P < 0.005), and with more awakenings lasting more than 3 minutes (2.1 ± [1.5] vs 0.6 ± [0.8]; P < 0.005). These findings were confirmed by actigraphic monitoring that revealed lower sleep efficiency (90 ± [5]% vs 94 ± [3]%; P < 0.05), more minutes of wake time (49 ± [21] min vs 28 ± [15] min; P < 0.05), and a trend toward more awakenings longer than 5 minutes (1.8 ± [0.8] vs 1.2 ± [0.8]; P = 0.063). Our data demonstrated that 3 years after MHI without any discernible clinical sequel, adolescents still complain of sleep disturbances that could be confirmed by both polysomnographic and actigraphic monitoring.

Introduction

Head injuries are frequent events among children and adolescents. In the United States, approximately 100,000 children are hospitalized every year because of head injury [1]. Minor head injury (MHI) is characterized as a brain concussion that can cause a transient loss or impairment of consciousness (for less than 30 minutes), vomiting, and a short anterograde or retrograde amnesia. In MHI the Glasgow Coma Scale (GCS) score is 13 or higher [2]. Neurologic evaluation, including computed tomography (CT) and magnetic resonance imaging (MRI) scans, electroencephalogram (EEG), brainstem auditory-evoked responses, electronystagmograms, and audiograms, is normal or reveals minor, transient abnormalities [2]. However, although considered a “benign” event, MHI may have long-term effects generally termed postconcussive syndrome, or, in less-frequent cases, may result in posttraumatic stress disorder (PTSD).

Postconcussive syndrome includes headaches, memory and concentration impairments, anxiety, mood disorders, and sleep disorders [2]. There is some overlap with symptoms found in the PTSD, which is a mental disorder consisting of flashbacks, nightmares, and an inability to cope with daily life events. The syndrome primarily affects adults and includes two types of sleep disturbances as part of the diagnostic criteria (based on the DSM-IV): re-experiencing events (nightmares, Criteria B) and a hyperarousal state (difficulty initiating and maintaining sleep, Criteria D). There is controversy as to whether MHI can cause PTSD because of the loss of consciousness and the posttraumatic amnesia, which occur in the event [3].

Adolescents and young adults who have undergone MHI may suffer from sleep disorders without necessarily having other symptoms of the postconcussive syndrome or PTSD. Subjective evaluation of individuals after MHI revealed complaints of difficulties in initiating and maintaining sleep, early morning awakenings, decreased daytime performance, and a generally decreased sleep quality [4], [5]. Adult PTSD patients also complained of nightmares, but these did not necessarily exist in children with PTSD [6]. Few studies have attempted to objectively measure sleep behavior after MHI. In the acute phase after head injury in children, Lenard and Pennigstroff [7] found an increase in stage 2 (“light sleep”) and a decrease in stages 3-4 (“deep sleep”) with no consistent changes in percentage of rapid eye movement (REM) sleep. They also found more spindle activity in stages 2-3 and increased REM density. In contrast, Harada et al. [8] found a decrease in spindles and K-complexes during NREM sleep and decreased REM activity. Enomoto et al. [9] reported EEG changes in 42.5% of 280 children under 15 years of age in the acute phase after MHI. EEG abnormalities included an increase in slow-wave activity (associated with deep sleep) that had resolved during follow-up examinations. Parsons et al. [10] found similar results among adolescents with MHI.

All of the above-mentioned findings refer to the effects of MHI on sleep in the acute phase. The long-term effects of MHI on sleep in adolescents have not yet been studied consistently. Thus the purpose of our study was to characterize subjective and objective sleep abnormalities of adolescents who had experienced MHI and consequently complained of sleep disorders at the chronic phase after the injury.

Section snippets

Subjects

The patients were selected from the archives of Rambam Medical Center in Haifa, a tertiary hospital, which is the largest in the north of Israel. The study was approved by the Human Subject Committee of the hospital. A list was formed of all patients 10-18 years of age who had been admitted to the hospital between the years 1993 and 1996 after MHI (ICD-10 code S06.0) with a GCS of 13 or above on admission to the emergency department. A telephone survey of 50 of these patients was conducted

Questionnaire

Table 1 lists the responses (ranging from 0 = “none” to 4 = “extremely severe”) of our patients to questions related to the postconcussive syndrome. Results ranging from 2-4 were considered moderate to extremely severe and were therefore significant. Sixty-three percent of the subjects complained of significant amnesia regarding the MHI event but fewer complained about retrograde amnesia or amnesia of events after the head injury. Seventy-four percent of the subjects complained of significant

Discussion

This study demonstrates that 3 years after a MHI without any important known clinical consequence, adolescents complained of significant sleep disturbances that were validated by objective sleep monitoring. Both polysomnography and home actigraphy revealed similar results, including decreased sleep efficiency, with increased wake time and more frequent prolonged awakenings from sleep in the study group. Because sleep latency was similar in both study and control groups, it is likely that the

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