厚生連医誌

原第１４巻

１号

７〜９ ２００５

著

Measurement of psychic fatigue by a flicker in our employees
suffering the Mid Niigata Prefecture Earthquake in２００４
Department of pathology, Pathology Center ; Industrial physician and First−class working environment
measurement expert

Toshihiko Ikarashi
Objective : Psychic fatigue in close relation with post
−traumatic stress disorder（PTSD）was studied in our employees with a portable flicker examiner in the third week
after the strong earthquake hit on October ２３rd. in ２００４．
Study design : Thirteen cases were examined with aflicker marketed as "Mepica" by Hirobo Co. The degreeof mental fatigue was classified based on the document ofmaker's announcement and, furthermore, reevaluated statistically by ５−point scale. Results : On the５−point−scaled evaluation of psychic fatigue, our cases were
judged to be the healthy group with the point of ３．
３± ０．
２（mean ± standard deviation）．The coefficient ofvariance was６．
３％，which being less than１０％ and, furthermore, regarded as a less variance and an adequate precision. Conclusion : We could objectively judge the psychic fatigue of the employees who suffered an earthquake.
The portable flicker can be one of the useful tools forevaluating the psychic fatigue certainly because of its low
coefficient of variance.
Key words : the Mid Niigata Prefecture Earthquake in
２００４，Niigata−ken Chuetsu Jishin, earthquake in Niigata−prefecture Chuetsu−district, Nagaoka district, psychic
fatigue, post−traumatic stress disorder（PTSD），flicker,
Mepicareaction has been used conventionally because of its simple processing and stable results. Although a flicker had
been hard to handle because of its hugeness as an instrument, its utility value rose still more because of its miniaturization.
We had a pretty strong earthquake in Niigata−prefecture Chuetsu−district, on October ２３ in ２００４，so−called
the Mid Niigata Prefecture Earthquake in ２００４（in English）or Niigata−ken Chuetsu Jishin（in Japanese）．Bothour homes and workplace were destroyed and many employees were completely defeated physically and mentally.
The unhealthy rate worse from １０．
３％ to ３３．
３％ before
and after the earthquake respectively and ７４．
２％ of subjects complained medical problems based on the interview
survey for ２，
３１７ adult refugees（８０％ was more than ４０years old）
at the second week after the earthquake reported
from the Division of Health in the Department of Welfareand Health in Nagaoka City Government in November，
２００４．For earthquake victims with trauma reaction in refuges the mental intervention method for post−traumaticstress disorder（PTSD）was regarded to be of paramountimportance, but there were few reports pointing out thenecessity to reveal a health investigation in workplaces.
We used a portable flicker instrument, measured the psychic fatigue of suffered employees in our workplace, andreported in this paper.

Introduction
Materials and Methods
On an industrial health care, both the excessively heavylabor as physical fatigue and the mental health care forpsychic fatigue become important lately. In the latter case,
it is important for health supervisors to measure the degrees of both stress and psychic fatigue adequately.
At the health management in industrial workplaces byhealth supervisors the investigation consisted of a workingenvironment, a working procedure, a healthy examination,
and a degree of fatigue judgment. The measuring methodsof fatigue included followings：! a fatigue awarenessquestionnaire test or a flicker test for the measurement ofpsychic fatigue, and " a tapping test, a naming test ofcolor, a knee jerk test, a passometer, or a urinary protein
concentration per serum creatinine of １g for the measurement of physical fatigue. For a measurement of psychic fatigue the flicker test designed for an optic−brainCases : We examined thirteen full−time employees inPathology Center of Niigata−prefectural Public Welfare
Association of Japan Agricultural Cooperatives（JA）in
Nagaoka city, consisted of nine men and four women,aged from ２５−to ５７−year old. Their homes lay in Koshiji town, Tochio city, and Nagaoka city just close to theepicenter of earthquake with a magnitude intensity of６．
８．
Examined date : We measured on the ２０th day after
the occurrence of earthquake, sufferers were thought tohold some expectation of recovery in spite of many successive aftershocks. It was also at １６：０
０ on Friday when
the load of duties was greatest among whole workinghours.
Examiner and Method : The measuring method was in-―7―

Measurement of psychic fatigue by a flicker in our employees suffering the Mid Niigata Prefecture Earthquake in２００４

structed to examinees by the same person that mastered
the machinery. The measuring machinery aimed to measure a fatigue of brain（digital flicker HE−１００ marketed
as Mepica by Hirobo Co, address：〒７２６−８６１４ ５３０−２１４，Motoyama−cho, Fuchuu−city, Hiroshima−prefecture, phone：０８４７−４１−６
７８０，FAX：０８４７−４
１−８９０２，
homepage address : http : //www.hirobo.co.jp/newdiv/mepica/mepica.html, Photo １：external appearance of Mepica）．
Evaluation : The degree of mental fatigue was judged
on the criteria of fatigue classification based on the document of maker's announcement and, furthermore, reevaluated statistically by so−called ５−point scale（Table１）．

Results
Without considering the generation of cases, the observed flicker values were３０．
７in the minimum and ３５．
２
in the maximum. On the revised classification by ５−point scale according to the generation, the minimum
value was ２ and the maximum one was ５，with ３．
３±０．
２ as mean value ± standard deviation. In other words
the mean value of whole employees in our workplace was３．
３ and all cases were judged being in the mentally
healthy group.
The coefficient of variance was６．
３％，which being lessthan １０％ and, furthermore, regarded as a less varianceand an adequate precision.

of employees accumulated, which was lucky that we wereable to confirm employees in a comparatively good state
on mental health. We confirmed the vigor of employees
to recovery from the earthquake−induced damage.
Though unbecoming to a medical article, we concluded
with the words "Never be depressed by the earthquake,we will do our best to reconstruct."

Supplementary
The health counseling on the phone for earthquake−suffered employees was provided by Niigata Industrial
Health Promoting Center of Japan Labour Health andWelfare Organization（http : //www.niigataOHPC.rofuku.
go.jp／）from November２，２００４（private free dial：０１２０−７５６−０６７，toll free）．

Reference
１． Industrial health. Ikarashi's Medical ABC understandable even by a cat−Clinicopathological mechanism andits medical strategy−，ed. Toshihiko Ikarashi，
４３rd ed,Pimento Press, Nagaoka，
２００５．
（５１．
８GB, Softs : Windows , Exel , PowerPoint （ Microsoft ）， Photoshop（Adobe），Ichitaroh（Justsystem），and DocuWorks
Desk（Fuji Xerox））

和 文 抄
Discussion録

新潟県中越地震被災後事業所従業員の精神的疲労のフリッカー測定による判定に関する検討

Lately both an excessively heavy labor and a mental
health care have been emphasized from an accident suitand a side of compliance. Since the Dentsu court, thecompliance of the safe（health）consideration duty of aworker becomes more important for an enterprise as a responsibility based on the Occupational Safety and HealthAct. Five managements in an industrial health service as
duties were legally binding and, furthermore, the healthcare in such a disastrous situation should be also emphasized. It was interesting that we were able to inspect objectively the psychic disturbance of employees who experienced a tragic earthquake with a portable flicker of asimple instrument.
In Kobe earthquake（so−called Hanshin−Awaji
Daishinnsai）the１０％ of refugees in the temporary houses
developed PTSD one year later. Our some staffs should
also live in the temporary houses as refugees, one ofwhom held a new−born infant. In these circumstances,
we investigated the staff's fatigue on the day when several
weeks had passed from the disastrous day and the fatigue

病理センター；産業医・第一種作業環境測定士
い か ら し としひこ

五十嵐俊彦
目的：余震の治まらない地震発生２０日目の週末・業務終了直前において、被災事業所従業員の精神的疲労の程度をフリッカーを用いて測定した。対象と方法：対象は１３名の男女で、ヒロボー社製メピカによる点滅光源の識別周波数を測定した。疲労度の判定
は、業者作成の疲労判定表に基づいた。成績：疲労の５ 段階評価上、３．
３±０．
２で、健康エリアと判定された。結論：被災地に居住する従業員の精神的疲労を客観的に判定でき、作業管理と健康管理上、有意義であった。
キーワード：新潟県中越地震、長岡地区、精神的疲労、心的外傷後ストレス障害（トラウマ反応、PTSD）、フリッカー、メピカ―8―

厚生連医誌

第１４巻

１号

７〜９ ２
００
５

Table１． the degree of fatigue in the age bracket based on the declared maker's value
five degrees offatigue／age
５（excellent）
４（healthy）
３（healthy）
２（healthy）
１（exhausted）

２
０

３
０

４
０３９．
５≦
３
７．
９≦
３
４．
３≦
３
２．
９≦
＜３２．
９３７．
９≦
３４．
７≦
３２．
９≦
３１．
９≦
＜３１．
９３７．
８≦
３５．
０≦
３１．
４≦
３０．
８≦
＜３０．
８

observation
value of flicker
３
３．
５
３
５．
５
３
３．
７
３
２．
８
３
３．
６３
３．
６３
３．
５
３
１．
３
３
１．
９
３
５．
２
３
４．
８
３
１．
５
３
０．
７

５−point
scale
２４
３
３
３３
３
３
４
５
４
３
３

Table２． Results
sex

age

male
male
femalemale
male
femalemale
male
female
male
male
male
female

２５
３４
３
６４
２４
６４
９４
９５
２
５
４
５
５５
６５
７
５
７

mean value＝３．
３±０．
２
coefficient of variance＝６．
３％（＜１０％）―9―

５０andabove
３
５．
１≦
３
１．
８≦
２
９．
４≦
２
７．
４≦
＜２７．
４