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Defense Technical Information Center 
Compilation Part Notice 

ADPO 10465 

TITLE: Usefulness of Sleep Records After Mild 
Head Trauma to Predict Shift Work Effectiveness 

DISTRIBUTION: Approved for public release, distribution unlimited 

This paper is part of the following report: 

TITLE: Individual Differences in the Adaptability 
to Irregular Rest- Work Rhythms/Status of the Use 
of Drugs in Sleep- Wakefulness Management [les 
Differences entre individus concemant les 
facultes d’ adaptation aux rythmes irreguliers 
activite-repos/Le point sur V utilisation des 
medicaments pour la gestion des periodes 

To order the complete compilation report, use: ADA388183 

The component part is provided here to allow users access to individually authored sections 
of proceedings, annals, symposia, ect. However, the component should be considered within 
the context of the overall compilation report and not as a stand-alone technical report. 


The following comnonent nart numbers comprise the comnilation renort: 

ADPO 1045 3 thru ADP010473 



Polish Air Force Institute of Medicine 
Institute of Psychiatry and Neurology 
Krasinskiego Str. 54 
01755 Warsaw 


Validity of polysomnography for determining the post-traumatic sequelae was evaluated in 33 male patients 
after a mild head trauma. The results indicate that shortly after the trauma accompanied by the brain 
commotion disturbances in sleep architecture can be detected by means of polysomnography. We also 
demonstrate that polysomnography is a sensitive method of evaluation of early post-traumatic alterations within 
the CNS. Based on the results of the present study we conclude that the described diagnostic procedure should 
become a steady element of the clinical evaluation and qualification of patients presenting with subjective 
symptoms as the sequalae of a mild head trauma. 


Minor head trauma (MHT) accompanied by 
brain concussions constitutes, as a clinical 
syndrome, about 2/3 of all the scull and brain 
injuries [8]. Most of the patients with the past 
history of the MHT recover within a few weeks 
without a need for a specific intervention. A third 
of the patients, however, develop the subjective, 
post-traumatic syndrome, and half of them never 
return to work. One year after the injuiy, 15% of 
the patients still complain of symptoms affecting 
their lifestyle [1]. Probably the pathological process 
developing after trauma could be considered the 
reason of complaints of sleep disturbances too. 
Therefore authors suspect that in early period after 
MHT patient can develop disturbances in sleep. 
We did not find any research work analizing a 
sleep pattern in a group of patients in early period 
after MHT. 

The present paper is a part of the research 
project carried out at the Polish Air Force Institute 
of Medicine (PAFIM), the Central Clinical 
Hospital of the Military Medical University School 
(CCH) and the Institute of Psychiatry and 
Neurology (IPN) in Warsaw. The project was 
devoted to evaluation of the state of the central 
nervous system in patients who had suffered from 
MHT. Here, we evaluated the sleep pattern of 
patients in early period after MHT. 


The study was conducted in a group of 40 
males aged 19-29 years (mean age 22.5 y) who 
were admitted to the Dept, of Neurology, PAFIM 

for the MHT accompanied by the consecutive brain 
concussion. The diagnosis was based on history, 
physical examination, and the computerized 
tomography (CT) results. The protocol of the study 
was approved by the Ethical Committees of both 
the PAFIM and the CCH and a written consent was 
obtained from all the subjects allotted to the study. 

Selection of the patients for the study was based 
on the following criteria: skull and brain injuries 
with brain commotion experienced for the first 
time shortly before the study (i.e., 24 - 96 hours 
before hospitalisation), 19-41 years of age, male 
sex, and no detectable mental disorders, somatic 
diseases or other physical abnormalities. In 
addition, no past history of abnormal EEC 
recordings and no family history of epilepsy were 

Seven patients should take medication and were 
excluded from the survey (two of them because of 
excessive emotional irritability, one because of 
serious dizziness and three because of persisted 
moderate and heavy headache). 

Control group consisted of 30 healthy paid 
male volunteers aged 19-29 years (mean age 22. 4y) 
with normal EEG in wakefulness. All examined 
persons described their sleep as good. None of 
them abused alcohol, took daytime naps, or 
underwent pharmacological treatment for at least 
four weeks before the sleep examination. 


After admission to the Clinic patients were 
assessed from the point of view of cause of trauma, 

Paper presented at the RTO HFM Workshop on “Individual Differences in the Adaptability to Irregular 
Rest-Work Rhythms/Status of the Use of Drugs in Sleep -Wakefulness Management”, 
held in Venice, Italy, 3-4 June 1999, and published in RTO MP-31. 


duration of unconsciousness, appearance and 
duration of posttraumatic amnesia (PTA). 

The injuries were evaluated using the Glasgow 
Coma Scale (GCS). Accordingly, the total score 
(ranging from 3 points for the most serious 
condition to 15 points for the least serious one) 
obtained after the assessment of the eye-opening 
capacity and the verbal and motor responses was 
used to divide the patients into the following 3 
groups: a) mild (scaled 13-15), b) moderate (scaled 
8-12), and c) heavy head trauma (scaled 3- 7). 

During the first 24 hours after the admission, the 
brain CT with no contrasting medium was 
performed. Normal images of the brain and the 
cerebellum with no detectable dislocations in the 
ventricular system were required for the inclusion 
of a patient in the study. All the CT images were 
examined by one and the same physician. 

On 3rd to 4th day after trauma, by means of 
“self-estimation sleep form” patients described 
their wake/sleep status, replying to 12 questions 
connected with the pattern of sleep after trauma, 
day sleepiness and naps. They compared it with the 
quality of sleep before MHT. 

On the 5th to 11th day after the trauma, 
polygraphic examinations were carried out on the 
Medelec-2 MC apparatus between 9.00-10.00 p.m. 
and 5.00-6.00 a.m. Standard technique 
polygraphic record and the criteria of visual 
scoring of somnogram stages according to 
Rechtsschaffen and Kales [2,14] were applied. 
Sleep was evaluated on the basis of the somnogram 
of the second night (the first night was considered 
as adaptation night). The same procedure of sleep 
examination was applied in control group after a 
normal activity during a week before the 

The data concerning sleep EEG were computer 
processed, mean values and standards deviations 
for 17 parameters were calculated. Students t-test 
was used for the statistical analysis of the results. 
P<0.01 was adopted as significant difference. 


Patient’s characteristics 

According to history data 18 patients (54.5%) 
suffered injuiy from fights, nine (27.3%) from car 
accidents and six (18.2%) from fall. Eleven of 
them (33.3%) were only confused or lost 
consciousness for less than dozen or so seconds. 
Twelve patients (36.4%) lost consciousness for 1 to 

20 minutes and ten patients lost consciousness for 
30 to 60 minutes. 

Retrograde amnesia (RA) occurred in every 
patient and lasted up to a few minutes after trauma. 
Posttraumatic amnesia (PTA) appeared in every 
patient as well, but the time of duration was up to 6 
hours. Data concerning RA and PTA have only 
approximate value, because in 27 cases memory 
improved before admission to the hospital. 

On the admission to the Clinic (first-third day 
after the trauma) the patients complained of a 
number of symptoms which disappeared after a few 
days. The complaints included headaches, 
dizziness, daytime drowsiness, nausea, and emesis. 
Headaches of mild and moderate intensity (not 
requiring any regular medication) as well as 
irritation and anxiety episodes were the longest 
lasting symptoms (6 subjects (18.2%) complained 
of them for 14 days after the trauma). 

According to the CGS, 25 (75.8%) patients 
were scored 15 points and 8 (24.2%) patients were 
scored 14 points. In the latter group, one point was 
subtracted from the highest score because the 
patients were able to open their eyes on demand. 

Self-estimation sleep form. 

All patients had no sleep disturbances and even 
naps before head trauma. According to the form 
results (table I) 22 subjects had different sleep 
abnormalities day sleepiness and naps after MHT. 
Five of them (gray mark on the table) had 
excessive sleep disturbances and woke up with the 
feeling of fatigue. 


Results of patients’ sleep examinations are 
shown in the table II. They are compared with the 
results of control group. Statistical analysis 
revealed a reduction of sleep cycle length 
(p=0.001) in patients. However an increase of cycle 
number (p=0.009) during a whole sleep period in 
subjects after MHT, caused that total amount of 
NREM sleep is similar in both groups. Another 
difference found in NREM sleep between two 
groups is decrease of stage 2 of sleep in patients 
(p=01). Analysing REM stage we observed 
shortening of REM sleep latency (p=0.0001). 

Polygrafic registration of sleep in patients took 
place between 4 to 11 days after trauma. In 19 of 
them from 4 th to 6 th day and in 14 from 8 th to 11 th 
day after MHT. Statistical analysis showed no 
difference between two estimated groups. 


As it is demonstrated in table I patients had 
some complaints connected with disturbances in 
wake - sleep cycle. Significant sleep differences 
were found in group of patients who, apart from 
other complaints, notified feeling of fatigue. 
However because of a small number of this group 
we should be careful in making a conclusion. 


Traumatic injury is mainly caused by 
displacement of intracranial structures in relation 
to the skull bones. A shift of these structures 
towards the trauma site creates a negative pressure 
which results in the formation of a vacuum on the 
opposite side of the brain. The vacuum sucks in gas 
bubbles to the cerebral cortex capillaries and 
breaks down small blood vessels and nervous tissue 
(the so-called cavitation phenomenon) [2]. After 
injury focal and diffuse pathological changes 
occur. MHT is mainly characterized by diffuse 
changes like diffuse axonal injury (DAI), diffuse 
microvascular damage (DMD) and delayed 
secondary injury (DSI). DSI is caused by an 
uncontrolled vicious cycle of biochemical events at 
cellular level set in motion by the trauma. DSI has 
come to be recognized as a major contributor to the 
ultimate tissue loss after MHT. The complex of 
pathological processes lead to necrosis and/or 
apoptosis of nerve cells [6,9]. 

Exposure to the linear acceleration forces 
brings about the most pronounced changes in the 
deep structures of the brain. Angular acceleration 
damages mainly the cerebral cortex of, particularly 
frontal and temporal lobes. - in which centres 
responsible for human behaviour, memory, 
cognitive and learning ability are found [18]. 
Experimental research works revealed that some 
cerebral structures, located in frontal and temporal 
lobes as well, are involved in creation of final 
sleep-wake status picture [10]. Thus behavioral and 
cognitive abnormalities are often found in patients 
with MHT. 

History of sleep disorders is one of factors 
affecting a quality of shift work. Traumatic brain 
injury can affect even temporary, activity of 
systems responsible for wake-sleep cycle. EEG 
sleep pattern of comatose patients after head 
trauma was the evidence of changed function of 
those systems [8]. Prigantano at al. [12] obtained 
single polysomnograms in a group of 10 subjects 

who had complains of disturbed sleep after closed 
injury. All of these patients had been comatose for 
at least 24 hours. The head-injured patients had 
less stage 1 sleep and a greater number of 

This research work has revealed that even after 
MHT, in early period after trauma, changes of 
sleep architecture can be observed. Decrease of 
stage 2 sleep is difficult to explain. It could be the 
result of affected function of structures (located in 
frontal and temporal lobes) involved in NREM 
sleep generating. In patients with diagnosed 
Alzheimer Disease (AD) pathological changes are 
especially found in frontal and temporal lobes. 
EEG sleep pattern of these patients disclosed poor 
biological efficiency and disturbances of REM 
stage [17]. 

Domzal et al. [3] discovered in their study that 
patients after MHT had a decrease of spindles 
activity - EEG elements found in NREM sleep 
pattern. Diminishing of spindle number results in 
reduction of stage 2 sleep. System consisting of 
reticular formation, thalamus and cerebral cortex is 
responsible for creation of spindles [11,13,16]. 
That is why affection of connections between these 
structures is thought as essential factor causing 
decrease of stage2 sleep. 

REM stage changes found in examined group 
may depend on affected function of centres located 
in cerebral hemispheres. Neurons generating REM 
stage are found in structures of brain stem but 
different cerebral nuclei influence on the final 
shape of this part of sleep [4,5,15,19]. 

REM sleep is thought to be responsible for 
brain metabolic regeneration [7]. Shortening of 
REM stage latency, duration of sleep cycle, and 
increase of cycle number could be the result of 
acceleration of the process. 


1. MHT affects a sleep architecture in early 
period after trauma. 

2. Polysomnography is a sensitive tool in 
discovering of sleep changes developing after 
MHT. It could help to improve clinical patient 
estimation and usefulness to perform shift 


Table II 

EEG sleep pattern of patients after mild head trauma versus control group. 

Parameters of EEG sleep pattern 

I^liffetence ' ' 5 

Record time (min) 






Time of sleep (min) 






Total sleep time (min) 






Wakefulness in sleep (%) 






Stage I (%) 






Stage 2 (%) 


H'- : "M 

— ■ 

1B1111I 1 


Stage 3 (%) 





p=0.42 | 

Stage 4 (%) 





i zrnmm 

Stage 3+4 (%) 





p=0.25 j 

Total NEEM sleep (%) 






Stage REM (%) 






Sleep latency (min) 





p=0.29 i 

Stage 3,4 latency (min) 





REM stage latency (min) 




p=0 0001 

Number of sleep cycles 





Number of awakenings 






Mean length of cycle (min) 




5ft ' 13.9:111 


Sleep efficiency (%) 






Sleep maintenance (%) 







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