Blindsight following visual cortex deafferentation disappears with purple and red stimuli: a case study.

We employed a redundant signal effect (RSE) paradigm to ascertain the role of the superior colliculus (SC) in blindsight. The RSE consists of the speeding of reaction time (RT) to double versus single stimuli. One patient with a unilateral lesion of the optic radiation and consequent hemianopia showed a RSE with pairs of visual stimuli presented across the vertical meridian despite seeing only stimuli in the intact hemifield. However, when, instead of achromatic stimuli we used short or long wavelength stimuli the implicit RSE disappeared. This result raises the possibility that implicit chromatic processing in the affected hemifield might have a different neural substrate following deafferentation with respect to lesion of the primary visual cortex.

Retinal eccentricity effects on reaction time to imagined stimuli.

To cast light on the possible neural substrate of visual imagery we tested normal participants and one hemianopic patient on simple reaction time (RT) to real and imagined visual stimuli. In one experiment participants were to detect as quickly as possible a luminous square presented at one out of two different retinal eccentricities. A well known effect with visual stimuli is that RT is slower for peripheral versus central stimuli. We found that imagined stimuli showed an eccentricity effect similar to that obtained with real stimuli. However, this was not the case in a patient with a hemianopic visual field loss (quadrantanopia) as a result of damage to the optic radiation. Even though the patient showed no difficulty in imaging stimuli in the affected hemifield she did not show an eccentricity effect as was the case in her intact side. In a second experiment, normal participants showed faster RT to stimuli of larger size with either real or imagined stimuli. Overall, these results show that visual perception and imagination share a similar visuotopic organisation that is disrupted following deafferentation of the visual cortex.

Reality orientation therapy to delay outcomes of progression in patients with dementia. A retrospective study.

OBJECTIVE: To evaluate the impact of continued Reality Orientation Therapy (ROT) in delaying the outcomes of dementia progression. DESIGN: Retrospective study. Data collection was based on review of clinical charts and on telephone interviews performed with patients or primary caregivers. SETTING: Day hospital of the Alzheimer's Disease Unit, Brescia (Italy). SUBJECTS: Seventy-four patients enrolled in at least one cycle of ROT from 1994 to 1998 were studied. INTERVENTIONS: Rehabilitative intervention based on formal ROT. MAIN OUTCOME MEASURES: This study analysed the time to the occurrence of any of the following: cognitive decline on Mini-Mental State Examination scores, urinary incontinence as an index of functional decline, institutionalization, and death. RESULTS: Data on a 30-month period after the first ROT session were analysed. We compared 46 patients (treatment group) who completed from 2 to 10 ROT cycles (corresponding to 8-40 weeks of training; mean = 15.48) with 28 patients (control group) who completed only one ROT cycle (4 weeks). Treatment group showed higher estimated survival rates than control group on cognitive decline (p = 0.022) and institutionalization (p = 0.002). The relative risks for cognitive decline and institutionalization in the control group compared with treatment group were 0.60 (p = 0.014), and 0.42 (p = 0.021), respectively. CONCLUSIONS: Continued ROT classes during the early to middle stages of dementia may delay nursing home placement and slow down the progression of cognitive decline.

The Itel-MMSE: an Italian telephone version of the Mini-Mental State Examination.

METHOD: We compared performance in an Italian telephone version of the Mini-Mental Status Examination (Itel-MMSE) with performance in the standard MMSE administered face to face to 104 inpatients affected by cognitive deficit. RESULTS: Their cognitive ability varied from mildly to severely impaired. Total scores of the two MMSE versions correlated strongly for all patients (r=0.85) and for very mildly (r=0.77), mildly (r=0.79), and moderately (r=0.72) demented. A weak but statistically significant correlation was observed for severely demented patients (r=0.46). The study establishes the validity and reliability of the Itel-MMSE as well as between rater and test-retest reliability. We calculated a regression equation for use in predicting MMSE scores from Itel-MMSE scores. Data fit a linear regression model.