Characterization of cognition in mild cognitive impairment with and without Parkinson's disease

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Screening tests can diagnose PD-MCI but do not give detailed cognitive profiles.

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Criteria based on a complete neuropsychological battery identify more PD patients with MCI.

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The overall cognitive profile is similar in PD-MCI and MCI.

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Neuropsychological batteries and definition of impairment cut-offs should be refined.

Referrals for Movement Disorder Surgery: Under-Representation of Females and Reasons for Refusal

OBJECTIVE

Referral of movement disorder patients for deep brain stimulation surgery was examined to determine whether referred patients were representative of gender proportions in our population, and reasons why patients do not proceed to surgery.

METHODS

Demographic information on referrals to the surgical program was retrospectively reviewed from our database and from a detailed chart review.

RESULTS

Although almost equal numbers of movement disorder patients are male and female, of the 91 patients referred for surgery, only 31% were female. Sixty-one percent of referred patients did not undergo surgery. Of these, the majority were denied for medical reasons, including cognitive decline (21%), psychiatric concerns (5%) and neurological reasons (42%).

CONCLUSIONS

Almost one-third of patients referred for movement disorder surgery were denied for medical reasons. This underscores the importance of evaluation of all potential patients by a multidisiplinary team to fully assess suitablity for stereotactic surgery. Interestingly, women were under-represented in those referred. In order that all appropriate patients have the opportunity to consider surgery, education of both physicians and patients, and different strategies to approach females regarding surgery may allow more patients to benefit from this treatment.

Surgery for Parkinson's disease improves disability but not impairment components of the UPDRS-II

The Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living (ADL) items have been described as reflecting both disability (true ADL items) and impairment (rather than ADLs). As a result of combining these scores, UPDRS part II scores may not accurately reflect the impact of surgery on ADLs [Hariz G.M., Lindberg M., Hariz M.I., Bergenheim A.T. Does the ADL part of the unified Parkinson's disease rating scale measure ADL? An evaluation in patients after pallidotomy and thalamic deep brain stimulation. Mov Disord 2003;18:373-81.]. The goal of the present study was to assess the metric properties of the ADL section of the UPDRS in terms of its ability to measure surgical change. We tested the effects of unilateral pallidotomy (N=14) and bilateral subthalamic nucleus (STN) DBS (N=11) on both disability and impairment components of the UPDRS-II at uniform follow-up assessment periods of 6 months and 1 year, with a subset of pallidotomy patients (N=9) re-assessed at 2 years. Across the follow-up periods in both patient groups, items identified as best reflecting disability showed significant improvement from pre-surgical levels, whereas items representing impairment showed no overall change. Consistent with this, change in total ADL scores was tempered by the inclusion of the impairment items. Because the measurement of a patient's functional status is important in determining the effectiveness of an intervention, analysis of appropriate items from the UPDRS ADL section is imperative.

Frames of reference for perception and action in the human visual system

A growing body of evidence demonstrates that vision for perception and vision for action are mediated by separate neural mechanisms. After briefly reviewing the neuropsychological evidence for this division of labor in the human visual system, we explore the evidence for a dissociation between perception and action in neurologically intact individuals. A number of studies have shown that unseen visual events can sometimes elicit movements of the hand and limb, despite the fact that subjects have no visual phenomenology of those events. Other work has shown that perceptual judgements about the location and size of objects can be quite different from the scaling of skilled actions directed at those objects. For example, size-contrast illusions, such as the Ebbinghaus illusion, have been shown to have little effect on the scaling of the grasp. Similar dissociations have been demonstrated in other studies in which psychophysical judgements about the dimensions of objects in the far peripheral field bear little relation to the calibration of grasping movements directed at those objects. Together with the neuropsychological work (and neurophysiological studies in the monkey), these findings provide compelling evidence for the operation of separate visual mechanisms in everyday life. In other words, what we think we see is not always what guides our actions.