The following are a study on "Cognitive Deficit" in Parkinson's and another
on driving and Parkinson's.
 
I thought I was the only one this way!<g>
 
<1>
Authors
  Cooper JA.  Sagar HJ.  Tidswell P.  Jordan N.
Institution
  Department of Clinical Neurology, University of Sheffield, UK.
Title
  Slowed central processing in simple and go/no-go reaction time tasks in
  Parkinson's disease.
Source
  Brain.  117 ( Pt 3):517-29, 1994 Jun.
Abstract
  Studies of cognition and motor control have independently suggested that
  patients with Parkinson's disease show deficits in both attentional
  control and the preprogramming of movement. However, few studies have
  examined directly the involvement of cognitive processes in the origin of
  their slowed response. We examined the performance of 100 Parkinson's
  disease patients on simple reaction time (SRT) and a series of go/no-go
  cross-modality choice reaction time (CRT) tasks, in which motor response
  was constant; correct positive responses required attention to a
  progressively increasing number of dimensions of visual and auditory
  stimuli. The results showed that Parkinson's disease patients became
  increasingly impaired in response speed as choice complexity increased.
  Slowed response speed in Parkinson's disease involved two factors: (i) a
  'perceptuomotor' factor which was constant across conditions and
  independent of choice complexity. Depression affected this factor
  selectively and independently of confounding associations with
  impoverished motor control; (ii) a 'cognitive-analytical' factor, which
  played an increasingly important role as complexity of choice increased.
  The characteristics of the relationship between response latency and
  cognitive complexity indicate that the deficit was due to a constant
  proportional slowing in cognitive speed across all SRT and CRT conditions.
  A cognitive deficit affecting the monitoring of stimulus-response
  compatibility may contribute to delayed response in Parkinson's disease.
  This cognitive-analytical deficit is present in early, untreated cases
  and, in contrast to perceptuomotor processes, is weakly related to
  depression.
 
<2>
Authors
  Cooper JA.  Sagar HJ.
Institution
  Department of Clinical Neurology, University of Sheffield, UK.
Title
  Incidental and intentional recall in Parkinson's disease: an account based
  on diminished attentional resources.
Source
  Journal of Clinical & Experimental Neuropsychology.  15(5):713-31, 1993
  Sep.
Abstract
  The recall of common objects and their spatial location was examined in 65
  patients with Parkinson's disease (PD) under conditions in which available
  attentional resources were manipulated by secondary task demands. PD
  patients were impaired at item recall particularly under intentional
  learning conditions but were unimpaired at recall of spatial location.
  These findings were similar in newly diagnosed, untreated cases as well as
  patients who had suffered with the disease for an average of 9.6 years.
  Test performance was not improved by levodopa therapy, despite it
  benefiting motor control, and was not impaired by anticholinergic
  medication. Item recall correlated significantly with other memory
  measures (particularly tasks of working memory) but only weakly with
  indices of physical disability and traditional frontal-lobe measures.
  Spatial recall, by contrast, correlated with memory quotient but no other
  cognitive measure and depression and disease duration failed to correlate
  significantly with performance on either recall task. These results are
  attributed to a deficit in attentional resources in PD that impairs
  performance most markedly for tasks and conditions that make the greatest
  demands upon effort.
 
<3>
Authors
  Cooper JA.  Sagar HJ.  Sullivan EV.
Institution
  University Department of Clinical Neurology, Royal Hallamshire Hospital,
  Sheffield, U.K.
Title
  Short-term memory and temporal ordering in early Parkinson's disease:
  effects of disease chronicity and medication.
Source
  Neuropsychologia.  31(9):933-49, 1993 Sep.
Abstract
  Studies of Parkinson's disease (PD) have shown impaired temporal ordering
  but interpretation may be confounded by task requirements and the effects
  of medication. We examined item recognition and recency discrimination in
  PD in relation to treatment and performance on other tests. Patients
  showed increased response latency and impaired recency discrimination only
  at short retention intervals. The deficits were greater in chronically
  medicated patients but treatment with levodopa, bromocriptine or
  anticholinergic drugs did not affect performance of newly diagnosed cases.
  The short-term memory deficits correlated with scores on tests of working
  memory, attention and executive function. These results do not indicate a
  generalised temporal ordering deficit in PD but suggest that much of the
  cognitive impairment in the disorder arises from attentional deficits
  affecting short-term and working memory.
 
<4>
Authors
  Cooper JA.  Sagar HJ.
Institution
  University Department of Neurology, Royal Hallamshire Hospital, Sheffield,
  U.K.
Title
  Encoding deficits in untreated Parkinson's disease.
Source
  Cortex.  29(2):251-65, 1993 Jun.
Abstract
  Short-term memory deficits are prominent in untreated Parkinson's Disease
  (PD) and speed of central processing is known to be abnormal. To
  investigate the relationship between these findings, a modification of the
  Brown-Peterson paradigm was given to newly diagnosed, untreated patients
  and healthy control subjects (HCS). The PD patients were impaired under
  conditions of long stimulus exposure but not when study time was short.
  Although patients displayed deficits in immediate recall, they were more
  impaired at longer test delays. They achieved fewer encoding operations
  per unit time, resulting in a divergence of group performance with
  increasing duration of stimulus exposure. Performance in the PD group did
  not associate with motor disability, disease duration or rating of
  depression. These results are discussed in terms of a unifying reduced
  central processing deficit that is evident in PD but is independent of
  physical symptoms.
 
 
John Cottingham    [log in to unmask] OR [log in to unmask]