Steven Massaquoi

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Despite the involvement of cerebellar ataxia in a large variety of conditions and its frequent association with other neurological symptoms, the quantification of the specific core of the cerebellar syndrome is possible and useful in Neurology. Recent studies have shown that cerebellar ataxia might be sensitive to various types of pharmacological agents,(More)
We compared procedural learning, translation of procedural knowledge into declarative knowledge, and use of declarative knowledge in age-matched normal volunteers (n = 30), patients with Parkinson's disease (n = 20), and patients with cerebellar degeneration (n = 15) by using a serial reaction time task. Patients with Parkinson's disease achieved procedural(More)
Eleven patients with relatively selective cerebellar degeneration and 11 normal control subjects underwent a comprehensive neurologic and neuropsychological examination. The neuropsychological tests assessed general intellectual ability, different aspects of memory (effortful, automatic, and implicit memory processes), speed of information processing, and(More)
There is evidence from animal experiments that the cerebellum and its associated brainstem circuitry are involved in the acquisition of the conditioned response. In order to obtain evidence for their involvement in humans, we studied classical delay conditioning, using the eye-blink conditioned response, in five patients with pure cerebellar cortical(More)
We compared the performance of 12 patients with cerebellar atrophy (CA) and 12 normal controls matched for age and education on the Tower of Hanoi, a nine-problem task that requires cognitive planning. CA patients performed significantly worse than controls on this task despite no difference in planning and between-move pause times. A reanalysis of the data(More)
OBJECTIVE To characterize kinematically any systematic aberration in multi-joint movements in cerebellar ataxia. METHODS Nine patients with cerebellar degeneration and nine normal subjects, mobile only at the shoulder and elbow of the right arm, were required to produce left-to-right cross-body linear hand trajectories on the horizontal surface of a(More)
OBJECTIVE To design a test of motor learning using arm movements in normal subjects and patients with cerebellar disease. METHODS Elbow angle was continuously displayed as a cursor (a dot) on a computer screen, and subjects made ballistic elbow flexion and extension movements to try to move the cursor between two targets on the screen. The relation(More)
A limit cycle mathematical model of the rapid-eye-movement (REM) sleep oscillator system has been developed from a structural model of interaction of populations of REM-on and REM-off neurons. The marked differences in latency, amplitude, and duration of the first REM sleep period seen with circadian variation and depressive pathology are modeled by(More)
OBJECTIVE To determine whether L-5-hydroxytryptophan (L-5-HTP) associated with eosinophiliamyalgia syndrome (EMS) like illness contains impurities in a fashion similar to that described in L-tryptophan associated with EMS. METHODS Members of a family who became ill after exposure to L-5-HTP were evaluated at the National Institutes of Health. Data from(More)