Enhanced Stimulus Strength Improves Visual Cognition in Aging and Alzheimer's Disease

Deficits in visual cognition in Alzheimer's disease (AD) arise from neuropathological changes in higher-order association areas of the cortex and from defective input from lower-level visual processing areas. We investigated whether enhanced signal strength may lead to improvement of visual cognition in AD. We tested 35 individuals with probable AD, 35 age-matched elderly control (EC) and 58 young control (YC) adults on letter identification, word reading, picture naming, discrimination of unfamiliar faces, and pattern completion. The contrast sensitivity step-difference across an independent sample of AD and EC groups was used in calculating an image filter, from which we produced stimulus-strength conditions of low-degraded, medium-normal, and high-enhanced. Using this filter we created a hypothetical proximal-strength equivalence between AD at medium strength and EC at low strength, and between AD at high strength and EC at medium strength. For letter identification, word reading, picture naming, and face discrimination, medium strength elicited AD accuracy levels and reaction times that were similar to those of EC at low strength. On picture naming, increased strength reduced perceptual-type errors for EC and AD and random errors for AD. For word reading, high strength elicited AD accuracy levels and reaction times that were equivalent to those of EC at medium strength. We saw no effect of signal-strength manipulation on performance of pattern completion, possibly owing to the complex cognitive demands of that task or to the inadequacy of the filter for its images. The results indicate that putative AD-EC differences in cognition directly reflect contrast sensitivity differences between the groups. Enhancement of stimulus strength can ameliorate vision-based deficits and lead to improvement in some aspects of cognitive performance. These results suggest new non-pharmacological avenues to explore in the attempt to improve cognition in elderly adults and especially in individuals with AD.

[1]  G. Gilmore,et al.  Enhanced stimulus contrast normalizes visual processing of rapidly presented letters in Alzheimer’s disease , 2005, Vision Research.

[2]  M. Dick,et al.  Vision in dementia: contrast effects. , 1996, Neurological research.

[3]  Kiralee M. Hayashi,et al.  Dynamics of Gray Matter Loss in Alzheimer's Disease , 2003, The Journal of Neuroscience.

[4]  J. Crawford,et al.  Improved detection of cognitive impairment with the NART: an investigation employing hierarchical discriminant function analysis. , 1990, The British journal of clinical psychology.

[5]  J. Gee,et al.  What's in a name: voxel-based morphometric analyses of MRI and naming difficulty in Alzheimer's disease, frontotemporal dementia and corticobasal degeneration. , 2003, Brain : a journal of neurology.

[6]  H. Braak,et al.  Alzheimer's disease: areal and laminar pathology in the occipital isocortex , 2004, Acta Neuropathologica.

[7]  G K Wilcock,et al.  Anatomical correlates of the distribution of the pathological changes in the neocortex in Alzheimer disease. , 1985, Proceedings of the National Academy of Sciences of the United States of America.

[8]  W. Chase,et al.  Visual information processing. , 1974 .

[9]  G. Gilmore,et al.  Spatial Contrast Sensitivity in Alzheimer's Disease: A Comparison of Two Methods , 1991, Optometry and vision science : official publication of the American Academy of Optometry.

[10]  B. Ober,et al.  New directions in the study of semantic deficits: a comment on Storms et al. (2003). , 2003, Neuropsychology.

[11]  Suzanne Corkin,et al.  Visual dysfunction in Alzheimer's disease: Relation to normal aging , 1991, Annals of neurology.

[12]  G. Gilmore.  Stimulus encoding in Alzheimer's disease: A multichannel view* , 1995 .

[13]  P. B. Cipolloni,et al.  Facial frequency manipulation normalizes face discrimination in AD , 2000, Neurology.

[14]  T. Bashore,et al.  Age differences in word and language processing , 1995 .

[15]  S. Corkin,et al.  Broad-band visual capacities are not selectively impaired in Alzheimer's disease , 1994, Neurobiology of Aging.

[16]  I. Bodis-Wollner.  Vulnerability of spatial frequency channels in cerebral lesions , 1976, Nature.

[17]  Patrick R. Hof,et al.  Functional neurobiology of aging , 2001 .

[18]  Charles J Duffy,et al.  A visuospatial variant of mild cognitive impairment , 2003, Neurology.

[19]  A. Cronin-Golomb,et al.  Characteristics of Visual Target Influence Detection of Change in Naturalistic Scenes in Alzheimer Disease , 2005, Cognitive and behavioral neurology : official journal of the Society for Behavioral and Cognitive Neurology.

[20]  G. Gilmore,et al.  Balint's syndrome in Alzheimer's disease: visuospatial functions. , 1990, The International journal of neuroscience.

[21]  C. E. Wright,et al.  Pathology of the optic nerve and visual association areas. Information given by the flash and pattern visual evoked potential, and the temporal and spatial contrast sensitivity function. , 1987, Brain : a journal of neurology.

[22]  Suzanne Corkin,et al.  Perceptual organization in Alzheimer's disease. , 1994, Psychology and aging.

[23]  A. Cronin-Golomb.  Color Vision, Object Recognition, and Spatial Localization in Aging and Alzheimer's Disease , 2001 .

[24]  R. Nebes,et al.  Sparing of semantic memory in Alzheimer's disease. , 1984, Journal of abnormal psychology.

[25]  Paul Atchley,et al.  Aging and visual masking: sensory and attentional factors. , 2004, Psychology and aging.

[26]  Loraine K. Obler,et al.  Naming Errors in Healthy Aging and Dementia of the Alzheimer Type , 1987, Cortex.

[27]  S Lakatos,et al.  A multimodal assessment of sensory thresholds in aging. , 1998, The journals of gerontology. Series B, Psychological sciences and social sciences.

[28]  F. Buonanno,et al.  Spatial vision in Alzheimer's disease. General findings and a case report. , 1985, Archives of neurology.

[29]  H. Spinnler,et al.  Cognitive modelling of face processing: Evidence from Alzheimer patients , 1995, Neuropsychologia.

[30]  H. Kirshner,et al.  The naming disorder of dementia , 1984, Neuropsychologia.

[31]  S. Folstein,et al.  "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. , 1975, Journal of psychiatric research.

[32]  M. Borchert,et al.  Assessment of visual impairment in patients with Alzheimer's disease. , 1987, American journal of ophthalmology.

[33]  J. Raven.  Coloured progressive matrices : sets A, Ab, B , 1956 .

[34]  M. Grossman,et al.  Visual perceptual functions predict instrumental activities of daily living in patients with dementia. , 2002, Neuropsychiatry, neuropsychology, and behavioral neurology.

[35]  M J Campbell,et al.  Laminar and regional distributions of neurofibrillary tangles and neuritic plaques in Alzheimer's disease: a quantitative study of visual and auditory cortices , 1987, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[36]  Leslie G. Ungerleider,et al.  The functional organization of human extrastriate cortex: a PET-rCBF study of selective attention to faces and locations , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[37]  S. Corkin,et al.  Visual dysfunction predicts cognitive deficits in Alzheimer's disease. , 1995, Optometry and vision science : official publication of the American Academy of Optometry.

[38]  M. Farah,et al.  Visual object and face processing in mild-to-moderate Alzheimer’s disease: from segmentation to imagination , 2003, Neuropsychologia.

[39]  R. Burchfield.  Frequency Analysis of English Usage: Lexicon and Grammar. By W. Nelson Francis and Henry Kučera with the assistance of Andrew W. Mackie. Boston: Houghton Mifflin. 1982. x + 561 , 1985 .

[40]  I. Bodis-Wollner,et al.  The measurement of spatial contrast sensitivity in cases of blurred vision associated with cerebral lesions. , 1976, Brain : a journal of neurology.

[41]  G. Gilmore,et al.  Magnocellular Deficit Hypothesis in Alzheimer's Disease , 2004 .

[42]  P. B. Cipolloni,et al.  Visual contrast enhances food and liquid intake in advanced Alzheimer's disease. , 2004, Clinical nutrition.

[43]  C. Duffy,et al.  Visual loss and getting lost in Alzheimer’s disease , 1999, Neurology.

[44]  M. Tovée,et al.  Contrast sensitivity and visual acuity in patients with Alzheimer's disease , 2000, International journal of geriatric psychiatry.

[45]  Suzanne Corkin,et al.  Incomplete achromatopsia in alzheimer's disease , 1993, Neurobiology of Aging.

[46]  G. V. Van Hoesen,et al.  The topographical and neuroanatomical distribution of neurofibrillary tangles and neuritic plaques in the cerebral cortex of patients with Alzheimer's disease. , 1991, Cerebral cortex.

[47]  W Makous,et al.  Visual mechanisms of spatial disorientation in Alzheimer's disease. , 2001, Cerebral cortex.

[48]  J. Cummings,et al.  The pattern of reading deterioration in dementia of the Alzheimer type: Observations and implications , 1986, Brain and Language.

[49]  J. Ricker,et al.  Visuoperceptual-spatial ability and visual memory in vascular dementia and dementia of the Alzheimer type , 1994, Neuropsychologia.

[50]  Jordan Grafman,et al.  Handbook of Neuropsychology , 1991 .

[51]  J. G. Snodgrass,et al.  A standardized set of 260 pictures: norms for name agreement, image agreement, familiarity, and visual complexity. , 1980, Journal of experimental psychology. Human learning and memory.

[52]  N L Foster,et al.  Visual-spatial deficits expalin visual symptoms in Alzheimer's disease. , 1996, American journal of ophthalmology.

[53]  P. Baltes,et al.  Sensory functioning and intelligence in old age: a strong connection. , 1994, Psychology and aging.

[54]  Adrian Ivanoiu,et al.  Semantic memory in Alzheimer's disease and the frontotemporal dementias: a longitudinal study of 236 patients. , 2006, Neuropsychology.

[55]  A. Cronin-Golomb,et al.  The impact of acuity on performance of four clinical measures of contrast sensitivity in Alzheimer's disease. , 2003, The journals of gerontology. Series B, Psychological sciences and social sciences.

[56]  M. Folstein,et al.  Clinical diagnosis of Alzheimer's disease , 1984, Neurology.

[57]  Grover C. Gilmore,et al.  Application of two-dimensional Fourier transforms to problems of visual perception , 1983 .

[58]  Ivan Bodis-Wollner,et al.  Visual Acuity and Contrast Sensitivity in Patients with Cerebral Lesions , 1972, Science.

[59]  Fred L. Royer,et al.  Models of contrast sensitivity in human vision , 1993, IEEE Trans. Syst. Man Cybern..

[60]  Grover C. Gilmore,et al.  Introduction to two-dimensional Fourier analysis , 1983 .

[61]  G. Gilmore,et al.  Stimulus Contrast and Word Reading Speed in Alzheimer's Disease , 2005, Experimental aging research.

[62]  Judith Ann Bornstein Turner.  Visual perception in normal aging and Alzheimer's disease: Influences on picture naming and recognition , 1990 .

[63]  Alfred W. Kaszniak,et al.  Communication and Cognition in Normal Aging and Dementia , 1987 .

[64]  P J Whitehouse,et al.  Contrast sensitivity in Alzheimer's disease: a 1-year longitudinal analysis. , 1995, Optometry and vision science : official publication of the American Academy of Optometry.

[65]  A. Kertesz,et al.  A study of language functioning in Alzheimer patients , 1982, Brain and Language.

[66]  C. J. Keemink,et al.  Spatial contrast sensitivity in unilateral cerebral ischaemic lesions involving the posterior visual pathway. , 1989, Brain : a journal of neurology.

[67]  T. Salthouse,et al.  Interrelations of age, visual acuity, and cognitive functioning. , 1996, The journals of gerontology. Series B, Psychological sciences and social sciences.

[68]  David P. Salmon,et al.  Recognition and naming of famous faces in Alzheimer's disease: A cognitive analysis , 1993, Neuropsychologia.

[69]  J. Becker,et al.  Understanding Impaired Analysis of Faces by Patients with Probable Alzheimer's Disease , 1995, Cortex.

[70]  G C Gilmore,et al.  Multidimensional letter similarity derived from recognition errors , 1979, Perception & psychophysics.

[71]  Mark Nawrot,et al.  Vision and cognition in Alzheimer’s disease , 2000, Neuropsychologia.

[72]  A. Cronin-Golomb,et al.  Vision in Alzheimer's disease. , 1995, The Gerontologist.

[73]  S. Corkin,et al.  Prevalence of visual deficits in Alzheimer's disease. , 1995, Optometry and vision science : official publication of the American Academy of Optometry.

[74]  Piero Antuono,et al.  Cytochrome oxidase in Alzheimer's disease: Biochemical, histochemical, and immunohistochemical analyses of the visual and other systems , 1997, Vision Research.

[75]  Sudha Seshadri,et al.  Visual Association Pathology in Preclinical Alzheimer Disease , 2006, Journal of neuropathology and experimental neurology.

[76]  G. Gilmore,et al.  Age effects in coding tasks: componential analysis and test of the sensory deficit hypothesis. , 2006, Psychology and aging.

[77]  S. Corkin,et al.  Category knowledge in Alzheimer's disease: normal organization and a general retrieval deficit. , 1992, Psychology and aging.

[78]  S. Corkin,et al.  Greater Relative Impairment of Object Recognition Than of Visuospatial Abilities in Alzheimer's Disease , 1996 .

[79]  Leslie G. Ungerleider,et al.  Dissociation of object and spatial visual processing pathways in human extrastriate cortex. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[80]  Spatial phase sensitivity of mechanisms mediating discrimination of small orientation differences. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.

[81]  E. Bisiach.  Perceptual Factors in the Pathogenesis of Anomia , 1966 .

[82]  David L. Wilson,et al.  An adaptive reference/test paradigm: Application to pulsed fluoroscopy perception , 1998 .

[83]  Shotai Kobayashi,et al.  Hemispheric lateralization of spatial contrast sensitivity , 1985, Annals of neurology.