CiteULike: tobymart's motion

Shaping by automated tracking of an arbitrary operant response.

Joseph J Pear — 2006-09-13T22:54:49-00:00

J Exp Anal Behav, Vol. 47, No. 2. (March 1987), pp. 241-247.

Although shaping is a widely accepted operant-conditioning procedure for establishing new responses, technological problems involved in specifying and recording precise approximations to the target response have hindered experimental analysis of the shaping process. The present study used a computer-controlled system that allows relatively precise procedural specification by continuous tracking of a pigeon's head and reinforcing successively closer approximations to contact of the head with an arbitrary fixed spherical region of 3-cm diameter. The procedure was demonstrated to be effective, in that shaping of the target response occurred rapidly for each of the 3 birds in the study.

The effects of guided imagery on anxiety levels and movement of clients undergoing magnetic resonance imaging.

MB Thompson — 2005-07-28T17:51:24-00:00

Holist Nurs Pract, Vol. 8, No. 2. (January 1994), pp. 59-69.

This randomized, experimental study examined the effects of guided imagery on anxiety levels and on movement of clients undergoing nonemergency magnetic resonance imaging (MRI). Subjects who listened to a guided imagery/relaxation tape (n = 20) before their MRI scan and used guided imagery during their scan had lower levels of state anxiety than the control group (n = 21). Based on subject report and operator report, the experimental group moved less frequently during the MRI than the control group. The results of this investigation support the use of guided imagery as a therapeutic intervention and Rogers' Science of Unitary Human Beings.

A study of the effects of patient anxiety, perceptions and equipment on motion artifacts in magnetic resonance imaging.

K Dantendorfer — 2005-07-28T16:18:33-00:00

Magn Reson Imaging, Vol. 15, No. 3. (1997), pp. 301-306.

We investigated to see if motion artifacts (MA) occurring in magnetic resonance imaging (MRI) are related to prescan anxiety measures and test the feasibility of identifying patients at risk for the development of MA before scanning. Furthermore, to determine a possible influence of constructional differences between a 1.5 and a 0.5 tesla scanner on the frequency of MA. Two hundred and ninety-seven first time MRI patients were surveyed before and after imaging with anxiety and attitude questionnaires. Frequency and impact on diagnostic quality of MA were documented. 12.8% of all scans showed MA not related to normal body pulsations. In 6.4% the diagnostic quality was impaired. Constructional differences did not influence the frequency of MA. Also, anxiety as determined with the most common anxiety measuring instrument was not related to the development of MA. Concern about the technical apparatus identified 70.6% of all individuals developing MA. Patients at risk for the development of MA can be identified prior to scanning. It seems necessary to further develop reliable methods to detect them and to evaluate strategies to prevent MA.

Behavioral training of motion control in young children undergoing radiation treatment without sedation.

KJ Slifer — 2005-07-06T14:19:34-00:00

J Pediatr Oncol Nurs, Vol. 11, No. 2. (April 1994), pp. 55-63.

Preschool-age children undergoing radiation treatment for malignancies often require daily sedation or general anesthesia to assure adequate motion control. A few older children with severe anxiety reactions, a history of behavior problems, or developmental handicaps have similar problems with radiotherapy. The use of sedation or anesthesia adds risk and expense to a procedure that does not require their administration for pain management. This report describes an alternative approach using behavior analysis to teach cooperation and motion control to preschoolers and older children with special needs. Outcome data are presented for 10 children between the ages of 3 and 7. Eight of the 10 appeared to benefit from the behavioral program. These eight cooperated with radiation treatments without the need for repeated sedation or anesthesia. The benefits and limitations of this approach are discussed along with the need for additional research.

Behavior analysis of motion control for pediatric neuroimaging.

KJ Slifer — 2005-07-06T14:14:45-00:00

J Appl Behav Anal, Vol. 26, No. 4. (1993), pp. 469-470.

Magnetic resonance imaging is a promising technological advance used for research and diagnosis of disease. The procedure has no risks, except when uncooperative patients require sedation. Four normal children participated in simulated scans to study the effects of (a) antecedent changes in the imaging environment and (b) operant conditioning of movement inhibition. Changing the environment can decrease movement, but operant contingencies were necessary to decrease movement to a level that, in most cases, would allow the procedure to occur without sedation.

Operant-contingency-based preparation of children for functional magnetic resonance imaging.

KJ Slifer — 2005-07-06T14:10:24-00:00

J Appl Behav Anal, Vol. 35, No. 2. (2002), pp. 191-194.

Functional magnetic resonance imaging (fMRI) is used to study brain function during behavioral tasks. The participation of pediatric subjects is problematic because reliable task performance and control of head movement are simultaneously required. Differential reinforcement decreased head motion and improved vigilance task performance in 4 children (2 with behavioral disorders) undergoing simulated fMRI scans. Results show that behavior analysis techniques can improve child cooperation during fMRI procedures.

Methodological issues in pediatric neuroimaging.

SY Bookheimer — 2005-07-04T16:33:40-00:00

Ment Retard Dev Disabil Res Rev, Vol. 6, No. 3. (2000), pp. 161-165.

The emergence of new technologies to study brain function in vivo has resulted in an explosion of interest in cognitive neuroscience within the last ten years. While most research in functional neuroimaging has been geared toward adult normal volunteers, the development of functional magnetic resonance imaging (fMRI) has made it possible to study neural development in normal children, as well as those with developmental disorders. This technology provides an unprecedented opportunity to expand our knowledge of brain function throughout childhood. A variety of technological, experimental, and practical difficulties are amplified when imaging children. This paper reviews some of the more challenging theoretical and practical concerns and provides suggestions for their management.

Autocorrection in MR imaging: adaptive motion correction without navigator echoes.

A Manduca — 2005-05-13T03:25:06-00:00

Radiology, Vol. 215, No. 3. (June 2000), pp. 904-909.

A technique for automatic retrospective correction of motion artifacts on magnetic resonance (MR) images was developed that uses only the raw (complex) data from the MR imager and requires no knowledge of patient motion during the acquisition. The algorithm was tested on coronal images of the rotator cuff in a series of 144 patients, and the improvements in image quality were similar to those achieved with navigator echoes. The results demonstrate that autocorrection can significantly reduce motion artifacts in a technically demanding MR imaging application.

Behavior modification and the management of mentally retarded dental patients.

R Kohlenberg — 2005-05-03T17:57:10-00:00

Journal of Dentistry for Children, Vol. 39, No. 1. (January 1972), pp. 61-67.

Patient management or behavior problems are a recurrent problem in pedontic practice, particularly if the practice involves mentally retarded patients. Behavior modification techniques have been effectively applied to many nondental office problems of the mentally retarded. The purpose of the present study was to apply behavior modification procedures to the management of mentally retarded dental patients and to test its effectiveness in producing improved dental chair behavior.

Whole-brain vascular reactivity measured by fMRI using hyperventilation and breath-holding tasks: efficacy of 3D prospective acquisition correction (3D-PACE) for head motion

Shinji Naganawa — 2005-04-28T17:01:10-00:00

European Radiology, Vol. 14, No. 8. (2004), pp. 1484-1488.

Motion correction in MRI using an apparatus for dynamic angular position tracking (ADAPT)

A Peshkovsky — 2005-04-22T18:11:01-00:00

Magnetic Resonance in Medicine, Vol. 49, No. 1. (31 December 2002), pp. 138-143.

Motion during MRI examinations is a serious problem that degrades the quality of the data (images) acquired. Motion can be corrected during the postprocessing of the data; however, this approach is suboptimal and is typically limited to in-plane or translational motion. An apparatus for dynamic angular position tracking (ADAPT) for prospective angular motion correction has been developed. This application is capable of <IMG SRC="/giflibrary/12/ldquo.gif" BORDER="0">tracking<IMG SRC="/giflibrary/12/rdquo.gif" BORDER="0"> the scanned region of interest by performing dynamic adjustments of orientation of the scanning plane. The operation of the apparatus is based on deuterium MR spectroscopy and does not rely on the use of magnetic field gradients. Orientation-sensitive deuterium quadrupolar interaction in a single crystal attached to a subject is used to monitor the angular position in magnetic fields. Measurements are performed with an independent spectrometer channel in the background of the MRI scans. This apparatus is very cost- and time-efficient because it utilizes the hardware already available on many spectrometers and can be used in parallel with MRI scans. Potentially, rotations by a fraction of one degree can be easily corrected and the angular position information can be rapidly updated. Magn Reson Med 49:138-143, 2003. © 2003 Wiley-Liss, Inc.

PROPELLER MRI: Clinical testing of a novel technique for quantification and compensation of head motion

Kirsten Forbes — 2005-04-22T18:08:40-00:00

Journal of Magnetic Resonance Imaging, Vol. 14, No. 3. (23 August 2001), pp. 215-222.

While head motion is considered a significant problem in magnetic resonance imaging (MRI), there is no data to quantify its extent, severity, or effect on image quality. PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) MRI offers a novel means of quantifying and compensating for head motion. We performed axial T2-weighted PROPELLER (motion corrected: P-CR; uncorrected: P-UNCR) and conventional MRI (CONV), with equal scan times, in five normal volunteers and 35 clinical subjects. Volunteers were examined lying still and performing two separate head movements (shake <IMG SRC="/giflibrary/12/ldquo.gif" BORDER="0">no<IMG SRC="/giflibrary/12/rdquo.gif" BORDER="0"> and nod <IMG SRC="/giflibrary/12/ldquo.gif" BORDER="0">yes<IMG SRC="/giflibrary/12/rdquo.gif" BORDER="0">) to assess detection and compensation of in-plane motion by PROPELLER MRI. Images were examined by three radiologists for motion artifact and for overall image quality. Head rotation and translation was detected in all subjects during each slice acquisition, with expected changes occurring with volunteer head motion. Motion artifact was less commonly seen on PROPELLER than CONV MR (<IMG SRC="/giflibrary/12/chi.gif" BORDER="0">2 test P < 0.001). PROPELLER was preferred over CONV in all subjects (P < 0.05) and P-CR was judged superior to P-UNCR (P = 0.02). Intracranial pathology was equally or better demonstrated with PROPELLER. PROPELLER MRI offers a means of quantifying head motion, reducing motion artifact, and improving image quality. J. Magn. Reson. Imaging 2001;14:215-222. © 2001 Wiley-Liss, Inc.

Prospective acquisition correction for head motion with image-based tracking for real-time fMRI

Stefan Thesen — 2005-04-22T18:07:12-00:00

Magnetic Resonance in Medicine, Vol. 44, No. 3. (1 September 2000), pp. 457-465.

In functional magnetic resonance imaging (fMRI) head motion can corrupt the signal changes induced by brain activation. This paper describes a novel technique called Prospective Acquisition CorrEction (PACE) for reducing motion-induced effects on magnetization history. Full three-dimensional rigid body estimation of head movement is obtained by image-based motion detection to a high level of accuracy. Adjustment of slice position and orientation, as well as regridding of residual volume to volume motion, is performed in real-time during data acquisition. Phantom experiments demonstrate a high level of consistency (translation < 40<IMG SRC="/giflibrary/12/mu.gif" BORDER="0" ALIGN="ABSBOTTOM">m; rotation < 0.05°) for detected motion parameters. In vivo experiments were carried out and they showed a significant decrease of variance between successively acquired datasets compared to retrospective correction algorithms. Magn Reson Med 44:457-465, 2000. © 2000 Wiley-Liss, Inc.

Motion correction with PROPELLER MRI: Application to head motion and free-breathing cardiac imaging

James Pipe — 2005-04-22T16:28:31-00:00

Magnetic Resonance in Medicine, Vol. 42, No. 5. (1999), pp. 963-969.

A method for motion correction, involving both data collection and reconstruction, is presented. The PROPELLER MRI method collects data in concentric rectangular strips rotated about the k-space origin. The central region of k-space is sampled for every strip, which (a) allows one to correct spatial inconsistencies in position, rotation, and phase between strips, (b) allows one to reject data based on a correlation measure indicating through-plane motion, and (c) further decreases motion artifacts through an averaging effect for low spatial frequencies. Results are shown in which PROPELLER MRI is used to correct for bulk motion in head images and respiratory motion in nongated cardiac images. Magn Reson Med 42:963-969, 1999. © 1999 Wiley-Liss, Inc.

An operant approach to rehabilitation medicine: overcoming learned nonuse by shaping

E Taub — 2005-04-21T15:37:57-00:00

Journal of the experimental analysis of behavior, Vol. 61, No. 2. (1994), pp. 281-293.

A new approach to the rehabilitation of movement, based primarily on the principles of operant conditioning, was derived from research with deafferented monkeys. The analysis suggests that a certain proportion of excess motor disability after certain types of injury involves a learned suppression of movement and may be termed learned nonuse. Learned nonuse can be overcome by changing the contingencies of reinforcement so that they strongly favor use of an affected upper extremity in the chronic postinjury situation. The techniques employed here involved 2 weeks of restricting movement of the opposite (unaffected) extremity and training of the affected limb. Initial work with humans has been with chronic stroke patients for whom the approach has yielded large improvements in motor ability and functional independence. We report here preliminary data suggesting that shaping with verbal feedback further enhances the motor recovery.