INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, VOL. 11: 925 (1996)

LETTER TO THE EDITOR

Non-Specificity of Pupillary Dilation Response to Tropicamide in Dementia of Alzheimer’s Type

Dear Editor

Scinto et al. reported on a potential non-invasive neurobiological test for Alzheimer’s disease by measuring the pupil dilation response to a cholin- ergic antagonist placed in the patients’ eyes (Scinto et al., 1994). They reported data of 14 individuals with probable dementia of the Alzheimer’s type (DAT), 32 normal controls, five non-demented suspect Alzheimer’s individuals and only four patients with a non-Alzheimer’s type dementia. Treloar et al. reported 10 vascular demented patients with a pupil dilation response indistin- guishable from that of 10 DAT patients (Treloar et al., 1995). But the clinical differentia- tion between vascular dementia (VD) and DAT is the most difficult step in the clinical diagnosis of dementing disorders and, as Scinto et al. replied, patients clinically diagnosed as VD frequently meet the neuropathological criteria for Alzheimer’s disease at autopsy (Scinto et al., 1995). We believe it important to report the pupil response, measured by an identical procedure to Scinto’s report, of a young patient with moya-moya disease, who suffered from pure VD.

The term moya-moya is a Japanese word for a cloud of smoke, and it has been used to refer to a network of small anastomotic vessels at the base of the brain around and distal to the circle of Willis, seen in carotid arteriograms, along with segmental stenosis or occlusion of the terminal parts of both internal carotid arteries (Adams and Victor, 1993). Our patient started with symptoms at an age of 26 years. Over a period of 4 years severe impairment of memory and thinking, finger agnosia, complete calculation disability, severe conduction aphasia (motor subtype) and visuospatial dysfunction

Address for correspondence: Doz. Peter Fischer, Psychiatrische Klinik, Waehringer Guertel 18-20, A-1090 Wien, Austria.

developed. This led to severe psychosocial impair- ment. The patient remains in a state of moderate dementia with a Mini-Mental State score between 12 and 14 for 3 years. Alzheimer’s disease can be excluded by the age of onset of dementia.

This patient with pure VD exhibited an extremely long-lasting and large dilation response, which would be the third highest response in Scinto’s study and was even higher than every dilation response of patients with probable DAT in our sample. We concluded that the pupil dilation response to tropicamide 0.01% is no specific neurobiological test for Alzheimer’s disease, but is also positive in at least some cases with vascular dementia.

PETER FISCHER JOSEF GRUNBERGER

University of Vienna

REFERENCES

Adams, R. D. and Victor, M. (1993) Principles of Neurology. McGraw-Hill, New York.

Fischer, P., Jellinger, K., Gatterer, G. and Danielczyk, W. (199 1) Prospective neuropathological validation of Hachinski’s ischemic score in dementias. J . Neurol. Neurosurg. Psychiat. 54, 580-583.

Scinto, L. F. M., Daffner, K. R., Dressler, D., Ransil, B. I., Rentz, D., Weintraub, S., Mesulam, M. and Potter, H. (1994) A potential noninvasive neuro- biological test for Alzheimer’s disease. Science 266,

Scinto, L. F. M., Daffner, K. R., Dressler, D., Ransil, B. I., Rentz, D., Weintraub, S., Mesulam, M. and Potter, H. (1995) Detecting Alzheimer’s disease- response. Science 267, 1580- 158 1.

Treloar, A., Assin, M. and Macdonald, A. (1995) Detecting Alzheimer’s disease. Science 267, 1578.

Treloar, A. and Macdonald, A. (1995) Pupillary response to tropicamide: Not a simple test for Alzheimer’s disease. Znt. J . Geriatr. Psychiat. 10, 994.

1051-1054.

8 1996 by John Wiley & Sons, Ltd.