Postural instability in Parkinson Disease: to step or not to step.

Postural instability is a key feature of Parkinson Disease that is associated with falls and morbidity. We designed a pull apparatus to quantitatively measure the force needed to pull subjects off-balance. Thirteen Controls and eight individuals with Parkinson Disease (PD) were evaluated. All individuals with PD reported subjective symptoms of postural instability and were symptomatic for approximately 9.4years when tested. No significant differences were found between Controls and PD subjects in the magnitude of force required to pull them off-balance. None of the Controls fell and all took a step into the direction of pull to maintain their balance. 59% of the time PD subjects fell because they did not take a step in the direction of pull to maintain their center of mass (COM) over their feet, thus indicating a deficiency in postural reflexes. If they fell on the first pull, PD subjects did not show a learning effect when pulled multiple times in the same direction. The utility of the Pull Test to detect postural instability is related to the subject's behavioral response, not the force needed to pull them off balance. Our findings may also help explain certain features of the PD gait as an attempt by subjects to avoid postural instability by not placing their COM in gravitationally unstable positions.

Alien limb syndrome secondary to multimodal treatment of recurrent oligodendroglioma.

We present a 41-year-old man who experienced alien limb syndrome as a complication of treatment for recurrent Grade III oligodendroglioma of the right parietal lobe. Alien limb syndrome is a rare phenomenon in which a limb performs involuntary actions and the affected individual feels a sense of estrangement towards the limb. It occurs most commonly as a result of corticobasal syndrome, though a variety of other etiologies have been reported. It is rarely associated with focal lesions, such as stroke or tumors.

Assessing reliable change using the repeatable battery for the assessment of neuropsychological status (RBANS) for patients with Parkinson's Disease undergoing deep brain stimulation (DBS) surgery.

Parkinson's disease (PD) is progressive neurological disease characterized by resting tremor, rigidity, akinesia, postural instability and cognitive changes. The symptoms of PD are debilitating and often become unsatisfactorily treated by medication. Deep brain stimulation (DBS) is an effective treatment to significantly reduce the cardinal motor symptoms of PD. However, the neuropsychological effects of this treatment are less clear. This study examined pre- to post-DBS scores on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) using Reliable Change Indices (RCIs) derived from 20 patients with PD who were medically managed, and then compared to 20 patients with PD treated with DBS and medication. When using group statistical analyses and false discovery rate correction, no significant differences between or within groups were evident at baseline or at follow-up. However, when using the RCIs more patients in the DBS group exhibited reliable change in RBANS scores than did the Med Tx group. Although preliminary, these RCIs provide clinicians and researchers a foundational tool for assessing the effects of interventions (e.g., DBS) independent of the effects of PD and measurement error when using the RBANS.

Cognitive change on the repeatable battery of neuropsychological status (RBANS) in Parkinson's disease with and without bilateral subthalamic nucleus deep brain stimulation surgery.

Cognitive change following bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) surgery in those with Parkinson's disease (PD) has led to equivocal results. The current study applied a standardized regression-based (SRB) method based on 20 medically managed PD patients and 20 STN DBS PD surgical patients who were administered the Repeatable Battery of Neuropsychological Status (RBANS). Of the medically managed PD participants, 94% remained stable compared to 73% of the DBS group. In the DBS group cognitive change was noted on the Total scale and the Immediate Memory Index. A secondary analysis also revealed reliable change on several subtest scores. Although preliminary, the current study provides change parameters for post DBS surgery on this brief battery.

Deep brain stimulation parameters associated with neuropsychological changes in subthalamic nucleus stimulation for refractory Parkinson's disease.

BACKGROUND/AIMS: Parkinson's disease (PD) is an idiopathic progressive neurological disorder. Improvement in motor function of PD patients has been established with subthalamic nucleus (STN) deep brain stimulation (DBS). While variations in DBS settings (i.e. amplitude, frequency and pulse width) on motor function have been explored, little data has evaluated the relationship of DBS settings on cognitive function. This study evaluated the extent to which DBS settings were associated with cognitive function. METHODS: The study was a prospective clinical trial of STN DBS for the treatment of refractory PD. Twenty patients were evaluated once preoperatively and an average of 5 months following bilateral STN DBS. Measures included a test of motor disability, a neuropsychological test battery and subjective mood measures of anxiety and depression. RESULTS: Motor function significantly improved following bilateral STN DBS. Compared to preoperative performance, verbal fluency declined while visuoconstructional skills improved. Amplitude and pulse width were significantly correlated with measures of cognitive function. Multiple regression found DBS stimulator settings, along with anxiety, to be significant predictors of cognitive measures. CONCLUSION: Increased amplitude and pulse width and decreased anxiety were associated with improved cognitive test scores. Although preliminary, these data have potential theoretical and clinical applications.

Lower serum ceruloplasmin levels correlate with younger age of onset in Parkinson's disease.

Ceruloplasmin functions as a ferroxidase in iron metabolism. Parkinson's disease (PD) is characterized by an increase in brain iron. We postulated that lower circulating ceruloplasmin levels in PD would result in rapid brain iron accumulation and an earlier age of onset. Consecutive PD patients were separated into subgroups with younger (< or = 60 years, n = 62) and older ages of onset (> 60, n = 29), and compared to non-PD controls (n = 40). A one-way ANOVA comparing ceruloplasmin levels showed a very robust effect [F(2,128) = 46.4, p < 1e-99]. Post hoc analysis demonstrated that the younger-onset PD subgroup [22.0 mg/dl +/- 6.5 SD] had a lower mean ceruloplasmin level compared to the older-onset PD subgroup [35.7 +/- 10.4] and controls [35.6 +/- 8.4], whose levels did not differ from each other. Ceruloplasmin levels showed robust correlation with age of onset in all 91 PD patients [r = 0.56, r(2) = 0.31, p < 0.0001] but not in the non-PD controls [r = 0.16, r(2) = 0.03, not significant]. Mode of onset and duration of PD showed no relationship to ceruloplasmin. Serum copper and ferritin, available in most patients, did not differ between the PD subgroups. Younger-onset PD patients have significantly lower levels of serum ceruloplasmin compared to those with older-onset PD. Ceruloplasmin may play a role in the etiopathogenesis of younger-onset PD patients and merits further study.

Analyzing the subcortical dementia syndrome of Parkinson's disease using the RBANS.

On mental status examinations, groups of equally impaired patients with subcortical (Huntington's disease, HD; Parkinson's disease, PD) or cortical (Alzheimer's disease, AD) dementias exhibit different patterns of neuropsychological deficits. Using the Repeatable Battery for Assessment of Neuropsychological Status (RBANS), classification accuracies of 90% or greater have been reported for individual patients with AD or HD. To test the generality of the RBANS classification algorithm, we studied patients with dementia (AD and PDD) and without dementia (PDND). Classification accuracies were AD: 87%, PDD: 78%, and PDND: 39%. Comparisons of performance on subtests of the RBANS showed that all groups performed more poorly on tests that require motor skill or rapid information processing and that memory performance by the PD groups was not improved by procedures that enhance encoding and facilitate retrieval. The RBANS is useful for discriminating patterns of cognitive impairment in PD and AD, but only if the diagnosis of dementia is established independent of the RBANS test results. Cognitive slowing is not specific to subcortical dementia and current concepts of memory dysfunction in PD may require re-examination.