Optical coherence tomography (OCT) use in non-Alzheimer’s disease (AD) dementias

27 May 2013

We read with great interest the article by Moreno and colleagues [1]. The authors should be congratulated on enlarging our knowledge on retinal nerve fiber layer (RNFL) thickness measurements in Alzheimer’s disease (AD) and other types of dementia. The results of this study show that optical coherence tomography (OCT) seems to be a useful tool for diagnosing dementia syndromes but does not seem to contribute to the differential diagnosis of different types of dementia. Nevertheless, we believe that some supplementary discussion of the problem is needed. Although the authors stated in their article that there were no studies on the RNLF thickness in non-AD dementias, in fact there were two studies on RNFL thickness in a type of dementia different from AD; we refer to the CADASIL syndrome (Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), considered a genetic form of small-vessel disease causing subcortical dementia. Thus, in 2007, Parisi et al. [2] reported a reduction of peripapillary RNFL thickness in six CADASIL patients. According to the authors, this morphological abnormality could be ascribed to an impairment of the retinal vascular supply leading to a global neuroretinal involvement. Recently, Rufa et al. [3] confirmed a decreased RNFL thickness in seventeen CADASIL patients with respect to controls, although no significant correlations were found between RNFL thinning and brain atrophy.

Andrzej Grzybowski1,2, Francisco J. Ascaso3,4
1Department of Ophthalmology, Poznan City Hospital, Poznań, Poland
2Chair of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland
3Department of Ophthalmology, ”Lozano Blesa” University Clinic Hospital, Zaragoza, Spain
4Aragon Health Sciences Institute, Zaragoza, Spain

References
[1] Moreno-Ramos T, Benito-Leon J, Villarejo A, Bermejo-Pareja F (2013) Retinal nerve fiber layer thinning in dementia associated with Parkinson's disease, dementia with Lewy bodies, and Alzheimer's disease. J Alzheimers Dis 34, 659-664.
[2] Parisi V, Pierelli F, Coppola G, Restuccia R, Ferrazzoli D, Scassa C, Bianco F, Parisi L, Fattapposta F (2007) Reduction of optic nerve fiber layer thickness in CADASIL. Eur J Neurol 14, 627-631.
[3] Rufa A, Pretegiani E, Frezzotti P, De Stefano N, Cevenini G, Dotti MT, Federico A (2011) Retinal nerve fiber layer thinning in CADASIL: an optical coherence tomography and MRI study. Cerebrovasc Dis 31, 77-82.

Comments

Submitted by JAD Admin, on

We thank Dr. Grzybowski and Dr. Ascaso for their interest in our article [1]. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease, clinically characterized by a variable combination of migraine, recurrent transient ischemic attack or lacunar strokes, cognitive decline, and mood disturbances [2]. Although cognitive impairment and dementia represent the second most common clinical manifestation in CADASIL [3], patients can remain without any cognitive decline for several years [4]. In the article by Parisi et al. [5], of the six CADASIL patients, only two had cognitive impairment (not dementia). Furthermore, in the article by Rufa et al. [6], of the 17 CADASIL patients, two patients were clinically asymptomatic, three had a history of migraine, and 13 had a history of recurrent ischemic attacks and strokes; none of them had full blown dementia. Hence, retinal nerve fiber layer (RNFL) in patients with CADASIL associated dementia has not been systematically studied. However, these preliminary results on CADASIL should encourage researchers to evaluate the extent of the reduction of the RNFL thickness in patients with CADASIL associated dementia.

Julián Benito-León1, 2, 3, Teresa Moreno-Ramos4, Alberto Villarejo1, 2, 3, Félix Bermejo-Pareja1, 2, 3

1Department of Neurology, University Hospital “12 de Octubre”, Madrid, Spain
2Complutense University, Madrid, Spain
3Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
4Department of Neurology, University Clinic Hospital "San Carlos", Madrid, Spain

References
[1] Moreno-Ramos T, Benito-Leon J, Villarejo A, Bermejo-Pareja F (2013) Retinal nerve fiber layer thinning in dementia associated with Parkinson's disease, dementia with lewy bodies, and Alzheimer's disease. J Alzheimers Dis 34, 659-664.
[2] Chabriat H, Joutel A, Dichgans M, Tournier-Lasserve E, Bousser MG (2009) Cadasil. Lancet Neurol 8, 643-653.
[3] Chabriat H, Bousser MG (2007) Neuropsychiatric manifestations in CADASIL. Dialogues Clin Neurosci 9, 199-208.
[4] Trojano L, Ragno M, Manca A, Caruso G (1998) A kindred affected by cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). A 2-year neuropsychological follow-up. J Neurol 245, 217-222.
[5] Parisi V, Pierelli F, Coppola G, Restuccia R, Ferrazzoli D, Scassa C, Bianco F, Parisi L, Fattapposta F (2007) Reduction of optic nerve fiber layer thickness in CADASIL. Eur J Neurol 14, 627-631.
[6] Rufa A, Pretegiani E, Frezzotti P, De Stefano N, Cevenini G, Dotti MT, Federico A (2011) Retinal nerve fiber layer thinning in CADASIL: an optical coherence tomography and MRI study. Cerebrovasc Dis 31, 77-82.