Sains Malaysiana 45(9)(2016): 1399–1403

Mild Cognitive Impairment does not Affect Pattern Electroretinogram in the Elderly - A pilot Study

(Kecelaan Kognitif Ringan tidak Memberi Kesan pada Pola Elektroretinogram dalam Kalangan Warga Tua - Suatu Kajian Awal)

SWEE PENG FUN¹, NORHANI MOHIDIN^2*, AZZATUL AINUR MOHD KAMAL¹, ZAINORA MOHAMMED¹ & BARIAH MOHD-ALI¹

¹Optometry & Vision Sciences Program, Faculty of Health Sciences, Universiti Kebangsaan Malaysia

Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Federal Territory, Malaysia

²Department of Optometry, Faculty of Health Sciences, Universiti Teknologi MARA, 42300 Puncak Alam, Selangor Darul Ehsan, Malaysia

Received: 31 December 2015/Accepted: 2 May 2016

ABSTRACT

The purpose of this study was to examine the effects of mild cognitive impairment on pattern electroretinogram (pERG) among urban elderly Malays. A total of 36 subjects aged 60 years and above comprising of 18 MCI subjects and 18 normal controls were recruited for this study. The inclusion criteria for both the MCI and normal subjects included best corrected distance visual acuity ≥ 6/9 (Snellen) with refractive error less than ±4.00 DS and/or ±2.00 DC (astigmatism), near visual acuity ≥ N8, absence or no previous history of any significant media opacities, retinal disorders and ocular pathologies. pERG was recorded with the RetiPort/Scan21 system in accordance with the International Society for the Clinical Electrophysiology of Vision standards. The target presented to subjects through a 19” CRT monitor was a black and white reversing checkerboard with luminance equal to 80 cd/m², contrast 97% and stimulus frequency 2.00 Hz (4 rev/s). Amplitudes and implicit times of P50 and N95 waves generated by the system were noted and compared between the two groups. The results showed no significant difference in the amplitude and implicit times between the right and left eyes so only the right eye was used for comparison between the MCI and control groups. The mean amplitude and implicit times of the right eye of the MCI and control groups were 1.86±0.65 μV, 56.27±6.20 ms and 1.54±0.74 μV, 56.15±4.98 ms, respectively. T-test showed no significant differences in pERG amplitudes and implicit times between MCI and the control groups. In conclusion, our results may imply that the inner retina is intact in early MCI elderly subjects.

Keywords: Elderly; mild cognitive impairment; pattern ERG

ABSTRAK

Penyelidikan ini bertujuan untuk mengkaji kesan kecelaan kognitif ringan (MCI) pada elektroretinogram (pERG) dalam kalangan warga tua Melayu di bandar. Seramai 36 orang subjek berumur 60 tahun ke atas terdiri daripada 18 orang subjek MCI dan 18 orang subjek normal sebagai kumpulan kawalan telah diambil ke dalam kajian ini. Kriteria kemasukan bagi kedua-dua kumpulan MCI dan kawalan termasuk ketajaman penglihatan terbaik dengan pembetulan ≥ 6/9 (Snellen) dengan ralat refraksi kurang daripada ± 4.00 DS dan/atau ± 2.00 DC (astigmatisme), ketajaman penglihatan dekat ≥ N8, tidak mempunyai sejarah kelegapan media, gangguan retina dan patologi okular. pERG direkodkan mengikut piawaian Persatuan Antarabangsa untuk Elektrofisiologi Klinikal Penglihatan. Sasaran petak segiempat berbalik hitam dan putih diberikan kepada subjek melalui monitor CRT 19” dengan kegerlapan bersamaan 80 cd/m², kontras 97% dan frekuensi stimulus bersamaan 2Hz (4 rev/s). Amplitud dan masa tersirat P50 dan gelombang N95 yang dijana oleh sistem tersebut dibandingkan antara kedua-dua kumpulan. Keputusan kajian menunjukkan tiada perbezaan yang ketara dalam amplitud dan masa tersirat antara mata kanan dan kiri, oleh itu hanya mata kanan digunakan untuk perbandingan seterusnya antara kumpulan MCI dan kawalan. Min amplitud dan masa tersirat pada mata kanan MCI dan kawalan adalah 1.86± 0.65 μV, 56.27± 6.20 ms dan 1.54± 0.74 μV, 56.15±4.98 ms. Ujian t menunjukkan tiada perbezaan bererti dalam pERG amplitud dan masa tersirat antara kumpulan MCI dan kawalan. Kesimpulannya, keputusan kajian ini mungkin membayangkan bahawa bahagian dalam retina masih dalam keadaan baik pada subjek warga tua MCI peringkat awal.

Kata kunci: Kecelaan kognitif ringan; paten ERG; warga tua

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*Corresponding author; email: norhani0887@puncakalam.uitm.edu.my