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Illuminance Effects Affecting to Cognitive Ability of the Elderly

고령자의 인지력에 미치는 조도의 영향

  • Kim, Myung-Ho (Department of Building Equipment System & Fire Protection Engineering, Gachon University)
  • 김명호 (가천대학교 설비소방공학과)
  • Received : 2018.11.28
  • Accepted : 2019.03.08
  • Published : 2019.03.31

Abstract

To study how illuminance affects cognitive ability of the elderly, the elderly's EEG, concentration, HRV and vibra image were measured in a test room with temperature $25[^{\circ}C]$, relative humidity 50[RH%] and air flow speed 0.02[m/sec] by varying illuminance to 100[lux], 300[lux], 600[lux], 1000[lux] and 1500[lux]. Ten active elderly males were selected as subjects. Experiment condition was fixed as 1met of activity amount where the subject is seated and relaxed with cloth amount of 0.7clo. As a result, 1000[lux] was found out to be the most pleasant illuminance for the elderly, because $M{\beta}$ increased by 66.35%, and $S{\alpha}$ increased by 31.57% when the elderly was under 1000[lux] of illuminance. Also, concentration under 1000[lux] increased by 8.83% compared to 100[lux], and the pattern of concentration maintained uniformly. SDNN increased by 74.94% under 1000[lux] compared to 100[lux]. Nervousness decreased by 97.23% under 1000[lux] compared to 100[lux]. Moreover, HRT notably increased and aggression remarkably decreased under illuminance of 1000[lux]. Thus, based on the fact that comfort, concentration and heart stability of the elderly reach the highest under 1000[lux], it is determined that the illuminance has to be considered foremost in designing the elderly's welfare facilities to raise their safety and level of independence.

조도가 고령자의 인지력에 미치는 영향을 연구하기 위하여, 온도 $25^{\circ}C$, 상대습도 50RH% 및 기류속도 0.02m/sec의 측정실에서 조도를 100lux, 300lux, 600lux, 1000lux 및 1500lux로 변화시키면서 고령자의 뇌파, 집중력, 심박동변이 및 진동 이미지를 측정하였다. 활동이 활발한 남성 고령자 10명을 피험자로 선정하였다. 측정 조건은 의자에 착석하여 안정을 취하고 있는 1met의 활동량으로 하고, 착의량은 약 0.7clo로 통일하였다. 측정 결과 고령자가 1000lux에 있을 때 미드 베타파가 66.35%가 증가했고, 슬로우 알파파는 31.57%가 증가된 것으로 미루어 고령자에게 1000lux가 가장 쾌적한 조도라는 것을 알았다. 또한 집중력은 100lux에서 보다 1000lux에서 8.83%가 증가했고, 집중력의 패턴도 균일하게 유지되었다. SDNN은 100lux에서 보다 1000lux에서 74.94%가 증가하였다. 신경과민은 100lux에서 보다 1000lux에서 97.23%가 감소되었다. 이외에도 1000lux에서 HRT는 뚜렷하게 증가되었고, 공격성은 현저하게 감소되었다. 따라서 고령자가 1000lux에 있을 때 쾌적성, 집중력 및 심장 안정도 등이 가장 높아지는 것을 기반으로 향후 노인복지시설을 설계하는 경우에는 무엇보다도 조도를 가장 우선하여 설계를 해야만 고령자들의 안전과 자립도를 높일 수 있다고 판단된다.

Keywords

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Fig. 1. Structure of Test Room

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Fig. 2. International 10-20 System

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Fig. 3. Vibra image measurement monitor

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Fig. 4. Relative Sα wave and Mβ wave due to illuminance variation

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Fig. 5. Concentration pattern variation due to illuminance variation (a) Concentration pattern at 100[lux] (b) Concentration pattern at 1,000[lux]

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Fig. 6. Recognition variation due to illuminance variation

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Fig. 7. SDNN and HRT variation due to illuminance variation

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Fig. 8. Vestibular emotional reflex variation due to illuminance variation

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Fig. 9. Cognitive ability variation analysis due to illuminance variation

Table 1. Specification of Test Room

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Table 2. Physical Condition of Subject

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Table 3. Statistical analysis of relative Sα wave and Mβ wave

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