Objective Quantification of Neuromotor Symptoms in Parkinson's Disease: Implementation of a Portable, Computerized Measurement Tool

Quantification of neuromotor symptoms with device-based measures provides a useful supplement to clinical evaluation. Research using the CATSYS has established its utility as a computerized measurement system to quantify neuromotor function. The primary objective of this study is to provide technical guidance on the use of the CATSYS in Parkinson's disease (PD). Forty-four patients with idiopathic PD and 28 healthy controls were prospectively recruited and evaluated with CATSYS, a portable, Windows-based system consisting of a data logger and four different sensors (tremor pen, touch recording plate, reaction time handle, and force plate for balance recording) for quantification of neuromotor functions. CATSYS discriminated between PD and controls on measurements of rest/postural tremor, pronation/supination, finger tapping, simple reaction time, and postural sway intensity and velocity. CATSYS measurements using the proposed test battery were associated with relevant clinician-rated Unified Parkinson's disease rating scale (UPDRS) items assessing tremor and bradykinesia. More work is warranted to establish CATSYS as a diagnostic/monitoring instrument in movement disorders using the proposed technical approaches

A questionnaire-based (UM-PDHQ) study of hallucinations in Parkinson's disease

Background: Hallucinations occur in 20-40% of PD patients and have been associated with unfavorable clinical outcomes (i.e., nursing home placement, increased mortality). Hallucinations, like other non-motor features of PD, are not well recognized in routine primary/secondary clinical practice. So far, there has been no instrument for uniform characterization of hallucinations in PD. To this end, we developed the University of Miami Parkinson's disease Hallucinations Questionnaire (UM-PDHQ) that allows comprehensive assessment of hallucinations in clinical or research settings.Methods: The UM-PDHQ is composed of 6 quantitative and 14 qualitative items. For our study PD patients of all ages and in all stages of the disease were recruited over an 18-month period. The UPDRS, MMSE, and Beck Depression and Anxiety Inventories were used for comparisons.Results and Discussion: Seventy consecutive PD patients were included in the analyses. Thirty-one (44.3%) were classified as hallucinators and 39 as non-hallucinators. No significant group differences were observed in terms of demographics, disease characteristics, stage, education, depressive/anxiety scores or cognitive functioning (MMSE) between hallucinators and non-hallucinators. Single mode hallucinations were reported in 20/31 (visual/14, auditory/4, olfactory/2) whereas multiple modalities were reported in 11/31 patients. The most common hallucinatory experience was a whole person followed by small animals, insects and reptiles.Conclusion: Using the UM-PDHQ, we were able to define the key characteristics of hallucinations in PD in our cohort. Future directions include the validation of the quantitative part of the questionnaire than will serve as a rating scale for severity of hallucinations

Early cognitive changes and nondementing behavioral abnormalities in Parkinson's disease

Early cognitive changes in patients with PD are often subtle and influenced by factors that interact with the disease process, including age of disease onset, medication, and the specific constellation of motor symptoms. These factors notwithstanding, ample evidence exists that specific cognitive changes occur early in the course of PD. This evidence does not imply that cognitive deficits are pervasive during the early stages. To the contrary, they are usually subtle and often difficult to detect without formal neuropsychological testing. Executive-function deficits are the most frequently reported cognitive problems and, given that executive skills are an integral part of many tasks, it follows that subtle difficulties may be seen on a wide range of cognitive measures, particularly in working memory and visuospatial dysfunction, two areas that rely heavily on executive skills. Whereas apraxia and language processing deficits occur infrequently, subtle changes in olfaction and contrast sensitivity have also been repeatedly observed. Finally, depressive symptoms are also common in the early stages of the disease. The significance of the early behavioral changes and their prognostic implications are largely unknown. Prospective studies are needed to understand the longitudinal course of early cognitive changes to determine whether they remain as circumscribed impairments or represent a precursor to a more widespread dementia

Handbook on the Neuropsychology of Aging and Dementia

XV, 527 p. 26 illus.online resource

Age of disease onset influences cognition in Parkinson's disease

It is controversial whether age of disease onset is related to cognitive decline in Parkinson's disease (PD). We administered 7 cognitive measures assessing visuospatial skills, memory, and executive functions to 222 patients with idiopathic PD and 108 normal control participants. Regression analyses demonstrated that older age of disease onset consistently predicted cognitive decline above and beyond normative aging and duration of illness. These findings suggest that older age of disease onset is a critical determinant of cognitive deterioration in PD. (JINS, 1998, 4, 285–290.

NMDAR-Dependent Control of Call Duration in Xenopus laevis

Many rhythmic behaviors, such as locomotion and vocalization, involve temporally dynamic patterns. How does the brain generate temporal complexity? Here, we use the vocal central pattern generator (CPG) of Xenopus laevis to address this question. Isolated brains can elicit fictive vocalizations, allowing us to study the CPG in vitro. The X. laevis advertisement call is temporally modulated; calls consist of rhythmic click trills that alternate between fast (∼60 Hz) and slow (∼30 Hz) rates. We investigated the role of two CPG nuclei—the laryngeal motor nucleus (n.IX–X) and the dorsal tegmental area of the medulla (DTAM)—in setting rhythm frequency and call durations. We discovered a local field potential wave in DTAM that coincides with fictive fast trills and phasic activity that coincides with fictive clicks. After disrupting n.IX–X connections, the wave persists, whereas phasic activity disappears. Wave duration was temperature dependent and correlated with fictive fast trills. This correlation persisted when wave duration was modified by temperature manipulations. Selectively cooling DTAM, but not n.IX–X, lengthened fictive call and fast trill durations, whereas cooling either nucleus decelerated the fictive click rate. The N-methyl-d-aspartate receptor (NMDAR) antagonist dAPV blocked waves and fictive fast trills, suggesting that the wave controls fast trill activation and, consequently, call duration. We conclude that two functionally distinct CPG circuits exist: 1) a pattern generator in DTAM that determines call duration and 2) a rhythm generator (spanning DTAM and n.IX–X) that determines click rates. The newly identified DTAM pattern generator provides an excellent model for understanding NDMAR-dependent rhythmic circuits