Fluctuations in tremor at rest and eye movements during ocular fixation in subjects with Parkinson's disease

Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada.
Parkinsonism & Related Disorders (Impact Factor: 3.97). 08/1998; 4(2):91-7. DOI: 10.1016/S1353-8020(98)00023-6
Source: PubMed


This exploratory study investigates possible relationships between fluctuations in tremor at rest (TR) and fluctuations in eye movement amplitude during ocular fixation. TR of the hand and eye movements were analyzed in five subjects with Parkinson's disease (PD) and five age-matched controls. TR was recorded using a position laser system and eye movements were recorded using an infrared reflectometry technique (Ober2). TR amplitudes were significantly larger in the group of subjects with PD than in the control group (p</=0.01). In addition, subjects with PD showed more fluctuations in their TR (p</=0.01). Eye movements did not present more fluctuations in amplitude during ocular fixation (p>/=0.05). Changes in TR amplitude were not systematically correlated with modifications of eye movement amplitude in either group. However, occasional but distinct monocular oscillations were found in subjects with PD. Coherence values between frequencies of TR from the tested hand (3.5-7Hz) and frequencies of oscillatory eye movements (within the same frequency band) were clearly higher for the eye ipsilateral to the side of the body most affected by the disease in three subjects with PD. It is believed that these monocular oscillations may be a consequence of PD. Results from two previously published exploratory studies are integrated with the present results and new avenues of research are proposed.

1 Follower
1 Read
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ventrolateral (VL) thalamotomy produced a marked reduction of oscillations related to the supraspinal components of Parkinson's disease tremor (4-7 Hz) and physiological tremor (8-12 Hz). Finger tremor was examined in nine patients undergoing unilateral VL thalamotomy and in nine age-matched controls. In comparison to the preoperative state, the relative percentage of power within the 7.6-12.5 Hz band did not increase after the surgical procedure. Furthermore, the amount of absolute power within the 7.6-12.5 Hz band was much lower for post-surgical patients in comparison to matched controls when periods of tremor having equal amplitudes were compared. These results suggest that VL thalamotomy interrupts a common circuit involved in the supraspinal component of both physiological and pathological tremors. We provide evidence that the thalamus may be involved in circuits generating physiological tremor in humans.
    Experimental Brain Research 06/2000; 132(2):216-22. DOI:10.1007/s002210000358 · 2.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The power distribution in the frequency spectrum of tremor is known to vary among individuals and its median power frequency declines with ageing. The purpose of the present study was to determine whether a reduction of the central component of physiological tremor would correlate with a reduction of motor performance. Then, the power distribution in the frequency spectrum of tremor from limb extremities might serve as an index of neural drive in healthy elderly subjects. Rest tremor, postural tremor from the finger, and pronation-supination at the wrist were recorded in 102 healthy nuns living in a convent (mean of 72┬▒12years). Results reveal that several elderly subjects possessed a power distribution of tremor very similar to that of much younger subjects (mean 27years┬▒3 SD), showing a preponderance of power within the 7.6- to 12.5-Hz band. Duration of pronation-supination cycles of these elderly subjects was, however, similar to that of other elderly subjects who had a preponderance of power within the 3.6- to 7.5-Hz band. Consequently, healthy elderly subjects who possessed a predominance of power within higher frequencies were not at an advantage over other healthy elderly subjects when performing a pronation-supination task. The age of subjects was, however, a better predictor or motor performance. In conclusion, the present findings suggest that, under normal physiological conditions, a reduction of the central component of physiological tremor does not induce a reduction of motor performance. Consequently, tremor recorded at limb extremities cannot be used as an index of neural drive.
    Experimental Brain Research 07/2001; 139(4):412-418. DOI:10.1007/s002210100780 · 2.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Parkinson's disease is a common disease of central nervous system among the elderly, and its complex symptoms bring some difficulties for the clinical diagnosis. In this study, a new method based on free spiral drawing was proposed to for quantitative evaluation of hand movement of patients with Parkinson's disease. According to the characteristics of hand movement in free spiral drawing, a set of parameters were defined and calculated. Experimental results showed that this method of evaluation was consistent with the clinical diagnosis. The proposed method based on free spiral drawing is effective in clinical diagnosis, and it provides a basis for quantitative evaluating the effectiveness of surgery and treatment.
Show more