Spiral analysis in Niemann-Pick disease type C.

Spiral analysis is a computerized method of analyzing upper limb motor physiology through the quantification of spiral drawing. The objective of this study was to determine whether spirals drawn by patients with Niemann-Pick disease type C (NPC) could be distinguished from those of controls, and to physiologically characterize movement abnormalities in NPC. Spiral data consisting of position, pressure, and time were collected from 14 NPC patients and 14 age-matched controls, and were analyzed by the Mann-Whitney U test. NPC spirals were characterized by: lower speed (2.67 vs. 9.56 cm/s, P < 0.001) and acceleration (0.10 vs. 2.04 cm/s(2), P < 0.001), higher loop width variability (0.88 vs. 0.28, P < 0.001), tremor (5/10 vs. 0/10 trials in the dominant hand, P < 0.001), and poor overall spiral rating (2.53 vs. 0.70, P < 0.005). NPC spirals also exhibited sustained drawing pressure profiles that were abnormally invariant with time. Other features, such as the tightness of loop widths, were normal. Our findings reveal that differing aspects of tremor, Parkinsonism, ataxia, and dystonia are quantifiable in NPC patients.

Spiral analysis-improved clinical utility with center detection.

Spiral analysis is a computerized method that measures human motor performance from handwritten Archimedean spirals. It quantifies normal motor activity, and detects early disease as well as dysfunction in patients with movement disorders. The clinical utility of spiral analysis is based on kinematic and dynamic indices derived from the original spiral trace, which must be detected and transformed into mathematical expressions with great precision. Accurately determining the center of the spiral and reducing spurious low frequency noise caused by center selection error is important to the analysis. Handwritten spirals do not all start at the same point, even when marked on paper, and drawing artifacts are not easily filtered without distortion of the spiral data and corruption of the performance indices. In this report, we describe a method for detecting the optimal spiral center and reducing the unwanted drawing artifacts. To demonstrate overall improvement to spiral analysis, we study the impact of the optimal spiral center detection in different frequency domains separately and find that it notably improves the clinical spiral measurement accuracy in low frequency domains.

Intention tremor of the head in patients with essential tremor.

Patients with essential tremor (ET) have kinetic arm tremor; this tremor can also have an intentional component. We are unaware of reports of intention tremor of the head in ET. Our aims were to describe, provide electrophysiological data and video documentation of, and estimate the prevalence of intention tremor of the head in our sample. Ten (9.0%; 95% confidence interval = 4.7%-14.3%) of 111 patients had intention tremor of the head; in 7 it involved the neck and in 3 the chin. These patients trended toward having more severe kinetic arm tremor and they had more severe intention tremor of the arms. These observations provide further support for the evolving view that the cerebellum may be involved in ET.

Risk factors for experiencing psychosis during cocaine use: a preliminary report.

UNLABELLED: Cocaine induced psychosis (CIP) is a common, but not universal side effect of cocaine abuse. Factors underlying the development and severity of CIP remain poorly understood. This study tests the hypothesis that earlier age of initiation of regular use may increase the likelihood of developing CIP, or the severity of CIP symptoms. METHODS: Cocaine use history and severity of CIP (if any) were assessed with the Cocaine Experience Questionnaire in 51 abstinent (3 weeks-1 year) cocaine dependent individuals. Subjects were divided into those with high and low CIP severity, and into those with early age of initiation of regular cocaine use, and later age of initiation. Various cutoffs between early and late age of initiation were used, ranging from 15 to 22 years. RESULTS: From ages 17 through 20, controlling for cumulative duration of use, severity scores were significantly higher for the early initiation group than for the later initiation group (p values ranged from 0.031 to 0.036). Cumulative duration of use, but not age of initiation, significantly predicted initial development of CIP (p=0.044). CONCLUSIONS: The data suggest that early age of initiation of regular cocaine use occurring during vulnerable periods of brain development, may lead to increased severity of CIP.