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Biomedical subjects

Y Yanada

Publications and source records attributed to Y Yanada.

5 recordsLinked to original sources
PubMed1992

A correlation study between blink reflex habituation and clinical state in patients with Parkinson's disease.

The neurologic states and activities of daily life of patients with Parkinson's disease were evaluated using a rating scale with subitems, and subsequently the neurologic disturbance scores and the daily activity impairment scores were obtained. Subjects consisted of 19 normal controls, and 55 ambulatory patients without marked dyskinesia who were on various anti-parkinsonian drugs. Blink reflex was elicited by paired electrical stimulation over the supraorbital nerve. The interval time between the conditioning stimulation and the test stimulation was set at 200 ms, and 5 serial ipsilateral maximal R2 amplitudes on the stimulated side were measured. The mean of the paired maximal R2 amplitude ratio (test/conditioning), expressed as a percentage, was defined as the habituation index. The habituation indices in normal controls and those with Parkinson's disease were 17.1 +/- 7.6 and 51.9 +/- 29.3, respectively (P less than 0.01). The degree of akinesia, rigidity, balance/gait and dysarthria was positively correlated with the habituation index (P less than 0.01), while tremor was not. On the whole the habituation index was found to have a significant correlation not only with the neurologic disturbance score but also with the daily activity impairment score (P less than 0.01).

Activities of Daily Living↗
PubMed1990

[Age-related interrelation of vibration perception thresholds and somatosensory evoked potentials in normal subjects].

In order to establish the age-related changes of vibration perception thresholds (VPTs) and somatosensory evoked potentials (SEPs), which are known to share a common afferent pathway in the central nervous system, 119 normal subjects ranging in age from the 20s to the 90s were studied. The VPTs of the index fingertip were measured at 63 Hz, 125 Hz and 250 Hz by a Rion vibrometer, nd the latencies of the SEPs to the median nerve stimulation (N9, N13 and N20) were simultaneously evaluated. The VPT, tended to elevate from the 40s, became increased towards higher frequencies (63 Hz less than 125 HZ less than 250 Hz) in the 80s to the 90s, whereas the VPT in younger ages showed just an opposite pattern (63 Hz greater than 125 Hz greater than 250 Hz). None of the height-corrected latencies of N9, N13, N20 and central conduction time (N20-N13) revealed a significant correlation between the VPTs at any frequencies. The age-related decline of vibration sense, therefore, could not be explained solely by the degenerative changes of he posterior column and/or the delay of the peripheral nerve conduction velocity. This phenomenon was rather thought to be compatible with an age-associated characteristics of Pacinian corpuscles.

Adolescent↗
PubMed1989

[Correlation between somatosensory evoked potentials and long loop reflexes--basic investigation and its application for multiple sclerosis].

Somatosensory evoked potentials (SEPs) and long loop reflexes (LLRs) to the median nerve stimulation were investigated on 25 normal controls and 25 patients with multiple sclerosis (MS). Fifteen normal controls were also subjected to LLR study by the common peroneal nerve stimulation. The mean height were 159 +/- 8.2 cm in normal controls and 160 +/- 8.9 cm in MS, respectively. LLRs were obtained with 100% reproducibility in all cases. Upper limb LLRs were recorded from m. abductor pollicis brevis by trigger stimulation during isotonic contraction of the thumb, while lower limb LLRs were recorded from m. peroneus longus by trigger stimulation during isotonic eversion of the foot. The threshold of LLR was lower than that of short latency reflex (H-wave) with the mean latency of 40.4 +/- 1.5 ms. The height of subjects revealed an obvious positive correlation not only with the latency of LLR but also with N 20 of SEP, whereas central conduction time was not. Furthermore, a significant correlation was present between the latencies of LLR and N 20, showing a twofold gradient of LLR against N20. There was a significantly prolonged latency difference between H-wave and LLR of lower limb as compared with that of upper limb. When the stimulation site was changed from the wrist to the elbow, the latency difference between M-wave and H-wave shortened. This fact, therefore, appears to be against "resonance hypothesis" that LLR is set off according to the intrinsic mechanical oscillation given to the muscle concerned.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗