Visual perception in prediagnostic and early stage Huntington's disease.
Disturbances of visual perception frequently accompany neurodegenerative disorders but have been little studied in Huntington's disease (HD) gene carriers. We used psychophysical tests to assess visual perception among individuals in the prediagnostic and early stages of HD. The sample comprised four groups, which included 201 nongene carriers (NG), 32 prediagnostic gene carriers with minimal neurological abnormalities (PD1); 20 prediagnostic gene carriers with moderate neurological abnormalities (PD2), and 36 gene carriers with diagnosed HD. Contrast sensitivity for stationary and moving sinusoidal gratings, and tests of form and motion discrimination, were used to probe different visual pathways. Patients with HD showed impaired contrast sensitivity for moving gratings. For one of the three contrast sensitivity tests, the prediagnostic gene carriers with greater neurological abnormality (PD2) also had impaired performance as compared with NG. These findings suggest that early stage HD disrupts visual functions associated with the magnocellular pathway. However, these changes are only observed in individuals diagnosed with HD or who are in the more symptomatic stages of prediagnostic HD.
O'Donnell
Brian F
BF
Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana 47405, USA. bodonnel@indiana.edu
Blekher
Tanya M
TM
Weaver
Marjorie
M
White
Kerry M
KM
Marshall
Jeanine
J
Beristain
Xabier
X
Stout
Julie C
JC
Gray
Jacqueline
J
Wojcieszek
Joanne M
JM
Foroud
Tatiana M
TM
D000328:Adult; D000704:Analysis of Variance; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D018911:Trinucleotide Repeats / Q000235:genetics*