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Biomedical subjects

M L Lin

Publications and source records attributed to M L Lin.

9 recordsLinked to original sources
PubMed1992

Gain effects on performance using a head-controlled computer input device.

The purpose of this study was to use a Fitts' task to (1) determine how control-display gain influences performance using a head-controlled computer input device; (2) compare relative sensitivity to gain and optimal gain between head control and hand/arm control; and (3) investigate control-display gain interactions with other task factors including target width, movement amplitude and direction. The task was a discrete target acquisition task using circular targets of 2.9 mm, 8.1 mm, and 23.5 mm, movement amplitudes of 24.3 mm and 61.7 mm, and eight radial directions including 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. Each device was operated at four gain levels. Ten subjects participated. The results indicated that gain had a significant effect on movement time for both types of pointing devices and exhibited local minimums. Discrete target acquisition at all gains was aptly described using Fitts' Law for both input devices. The mouse gain resulting in minimum movement time and RMS cursor deviation was between 1.0 and 2.0. The minimum movement time and RMS cursor deviation for the head-controlled pointer occurred at a gain between 0.3 and 0.6. Average movement time at the optimal head-controlled pointer gain had a slope of 169 ms/bit and was more than 76% greater than at the optimal mouse gain with a slope of 135 ms/bit. In addition, average RMS displacement was more than 27% greater for the head-controlled pointer at its optimal gain setting than for the mouse. Gain had the greatest effect for small target widths and long movement amplitudes using the head-controlled pointer. Average movement time increased 37% when increasing the head-controlled pointer gain from 0.6 to 1.2 for the small target width, but only increased 0.3% when increasing gain for the large target width. Average movement time also increased 12% when decreasing the head-controlled pointer gain from 0.3 to 0.15 for the long movement amplitude, but decreased 0.3% when decreasing gain for the short movement amplitude.

Ergonomics↗
PubMed1992

[The analgesic effect of subarachnoid administration of tetracaine combined with low dose morphine or nalbuphine for spinal anesthesia].

The analgesic effect of subarachnoid administration of tetracaine combined with low dose morphine or nalbuphine for spinal anesthesia was evaluated in 60 ASA physical status class I or II patients. Dextrose solution (10%) was added to 0.4 mg morphine or 0.4 mg nalbuphine to make a total volume of 2 ml, which was injected intrathecally with tetracaine in a double-blind, randomized fashion. Vital signs, sensory level, motor block, pain score, and side effects were recorded every 2 min for the first 15 min and then at 15, 30, 45, and 60 min and at 30-min intervals until the patient complained of pain. Side effects and opioid requirements were recorded for the first 24 h. Complete analgesia (time from injection to first report of pain) lasted 180 +/- 51.6 min in the control group and increased to 238 +/- 71 min in group with addition of 0.4 mg nalbuphine, 250 +/- 74 min in group with addition of 0.4 mg morphine (p less than 0.05). The effective analgesia (time from injection to first opioid requirement) also increased in groups of nalbuphine and morphine than the control group. No differences in complete or effective analgesia was found between groups in the presence of nalbuphine or morphine. Results indicate that the addition of 0.4 mg nalbuphine or morphine to hyperbaric tetracaine for spinal anesthesia improves the quality of intraoperative analgesia and can last into the postoperative period. Side effects were less in nalbuphine group than with morphine group.

Adult↗
PubMed1990

A method for evaluating head-controlled computer input devices using Fitts' law.

The discrete movement task employed in this study consisted of moving a cursor from the center of a computer display screen to circular targets located 24.4 and 110.9 mm in eight radial directions. The target diameters were 2.7, 8.1, and 24.2 mm. Performance measures included movement time, cursor path distance, and root-mean-square cursor deviation. Ten subjects with no movement disabilities were studied using a conventional mouse and a lightweight ultrasonic head-controlled computer input pointing device. Average movement time was 306 ms greater (63%) for the head-controlled pointer than for the mouse. The effect of direction on movement time for the mouse was relatively small compared with the head-controlled pointer, which was lowest at 90 and 270 deg, corresponding to head extension and head flexion, respectively. Average path distance and root mean square displacement was lowest at off-diagonal directions (0, 90, 180, and 270 deg). This methodology was also shown to be useful for evaluating performance using an alternative head-controlled input device for two subjects having cerebral palsy, and measured subtle performance improvements after providing a disabled subject with lateral torso support.

Adult↗
PubMed1987

Aneurysm of the sinus of Valsalva: a roentgenologic study of 105 Chinese patients.

Of 105 cases of lesions of the sinus of Valsalva found over a 25-year period at the Shanghai Chest Hospital, 90 were ruptured sinuses or sinus aneurysms and 15 were unruptured aneurysms. The cases were classified roentgenologically according to the method of Sakakibara and Konno: 64.5% were type I, 23.7% type II, 1.1% type IIIv, 6.4% type IIIa, 1.1% type IIIa + v, and 3.2% type IV. A new and simplified method of classification has been devised in the Shanghai Chest Hospital and shows the highest incidence to be the type of aneurysm of the sinus of Valsalva associated with ventricular septal defect. On aortography three types of morphologic changes--aneurysmal formation, enlargement of the sinus with no definite aneurysm, and sinus rupture with no enlargement or aneurysmal formation--are observed. Angiographically, shunting from ruptured sinus or sinus aneurysm begins in middiastole and gradually increases to end diastole. Aortic insufficiency, if present, usually begins in early diastole and extends over the whole diastolic phase in a decrescendo fashion. Special attention should be paid to the differentiation between ruptured sinus of Valsalva with or without aneurysmal formation and ventricular septal defect with aortic insufficiency.

Adolescent↗