here are a couple more from pub med
"Marjorie L. Moorefield" wrote:
> I'm back to seeing things in Black and White again.
>
snip
> just me,
> Marjorie
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J Neurol Sci 2000 Jan 1;172(1):7-11
Decreased color discrimination and contrast sensitivity in Parkinson's disease.
Pieri V, Diederich NJ, Raman R, Goetz CG
Department of Neuroscience, Centre Hospitalier de Luxembourg, 4 rue Barble,
L-1210, Luxembourg, Luxembourg.
Patients with Parkinson's disease (PD) often complain of blurred vision or even
of distinctive visual disturbances like hallucinations and illusions. Recent
studies have emphasized the potential influence of primary visual deficits of
color and contrast discrimination. To study primary visual function, we studied
color discrimination (CD) and contrast sensitivity (CS) during 'on' medication
in PD patients and compared them to non-PD subjects. Twenty one PD patients were
compared to 30 age-matched controls using CD tested by the D-15 Lanthony test
(D15) and the Farnsworth-Munsell 100 Hue test (FM) and CS tested by the
Pelli-Robson (PL) and the Vis-Tech tables (VT). We excluded subjects with a
visual acuity </=0.6 Snellen fraction or known ophthalmological diseases. PD
patients showed greater impairment on all visual tests than controls. This
difference was significant for the FM test (P<0.001), the spatial frequencies 12
and 18 cpd (cycles per degree) of the VT test (P<0.05) and both the monocular
and binocular PR tests (P<0.05). Most tests for CS and CD showed statistical
independency. CS deficits, but not CD deficits, correlated with age in both
patients and controls. This study documents major and independent impairment of
both color and contrast discrimination in PD patients. Further studies should
elucidate possible clinical implications and correlations, such as the frequency
of falls or visual hallucinations.
PMID: 10620653, UI: 20088930
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Brain 1995 Jun;118 ( Pt 3):771-8
Predominant affection of the blue cone pathway in Parkinson's disease.
Haug BA, Kolle RU, Trenkwalder C, Oertel WH, Paulus W
Department of Clinical Neurophysiology, Georg August University, Gottingen,
Germany.
Luminance contrast sensitivity and colour contrast thresholds were determined in
26 Parkinson patients and 17 normal controls of comparable age. They were
psychophysically tested with a colour monitor system. Stimuli consisted of
Gaussian enveloped luminance modulated or colour modulated (protan and tritan
axis) vertical sine wave gratings with a spatial frequency of 1 cycle/degree.
The stimuli subtended 4 degrees in diameter. Thresholds were determined using a
two alternative forced choice method. Three different experimental conditions
were explored: the detectability of stationary gratings, of moving gratings at
velocities of 0, 2.5 and 5.0 cycles/s, and the detectability of horizontal
square wave displacement at a frequency of 5 Hz for gratings of specified
contrast levels. Intergroup differences were evaluated using two-tailed t tests
with Satterthwaite corrections. Consistent and significant differences between
normals and patients were found for tritan stimuli in the static and both
dynamic conditions, and for luminance contrast stimuli in the displacement
condition. Protan stimuli were much less apt to detect differences between the
groups. We conclude that the retinal deficit of dopamine in Parkinson's disease
is reflected in diminished centre/surround inhibition and that these changes are
primarily apparent when vision is tested along the tritan axis, because blue
cones are sparsely distributed.
PMID: 7600093, UI: 95323455
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Ray Strand
...on the edge of the prairie abyss ......................
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48/47 dx/40 ? onset pd
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