Papers by Robert Van Boven
PubMed, Oct 1, 2018
Fear remains a major barrier to transparency of hospital errors.
Neurology, Dec 1, 1994
apour E, Yamada T. Blink reflex in patients with hemispheric cerebrovascular accident (CVA). J Ne... more apour E, Yamada T. Blink reflex in patients with hemispheric cerebrovascular accident (CVA). J Neurol Sci 16. Jaaskelainen SK. The blink reflex with stimulation of the mental nerve. Methodology, reference values, and some clinical vignettes. Acta Neurol Scand (in press).
Journal of Oral and Maxillofacial Surgery, Aug 1, 1991
American Journal of Ophthalmology, Oct 1, 2000
Outcome of surgery for thoracic outlet syndrome in Washington state workers' compensation To the ... more Outcome of surgery for thoracic outlet syndrome in Washington state workers' compensation To the Editor: We commend Franklin et al. 1 for trying to define the outcome of thoracic outlet syndrome (TOS) treatment in patients on workers' compensation. They reviewed one group of patients who underwent surgery and a second group who did not. Franklin et al. 1 correctly point out that "the two groups are not completely comparable so that strong conclusions are not warranted." In fact, this statement is not strong enough, because the two groups are not at all comparable and no conclusions should be drawn. Unfortunately, a comparison of the groups is exactly what the authors have made, and therefore the study is flawed and the comparison invalid. The selection criteria for surgery are not included, but it is reasonable to assume that surgery was offered to patients who had not responded to conservative therapy, and who were significantly disabled. The patients who did not undergo surgery were presumably those who had responded to conservative therapy and were not significantly disabled. This assumption is supported by the fact that the number of disability days in the 6 months prior to diagnosis was significantly higher in surgical versus nonsurgical patients (95 versus 65 days). The article tries to give a picture of the outcome of the surgery, which was a transaxillary first rib resection with or without scalenectomy, in over 90% of the patients. The complication rate was quoted as 31.7%; a list of the complications was included in the article. No comment was made about these complications, but an explanation is necessary. It should be noted that over half of these complications were pleural tears, and 3.2% were pneumothoracies. Entering the pleura is an accepted part of this operation, and it is only regarded as a complication if a pneumothorax requiring tapping occurs or if hospitalization is prolonged, which is seldom. A 17.7% incidence of sensory complaints is noted, which is usually caused by cutting or stretching the second intercostal brachial cutaneous nerve. This is a consequence of the transaxillary approach. It is an annoyance, but rarely a disability. The serious complications from this operation-complications that make symptoms significantly worse-are injuries to the brachial plexus or subclavian vessels. Apparently, none of these injuries occurred in this surgical series, as they are not mentioned. Franklin et al. 1 note that Dale 2 reported 52% of 259 surgeons who responded to a national survey had seen neurologic complications following TOS surgery. What is not stated is that these 259 surgeons had performed at least 5,000 TOS operations and that the permanent neurologic complications were no greater than 1% of the total. 3,p.163 Franklin et al. 1 also state that 32.7% of patients reported that overall quality of life was no better or worse after surgery. Can we assume that in the other 67.3% the quality of life was improved? This makes sense, as it is close to the 73.7% who would undergo surgery again. In TOS, it is well known that surgery improves, but rarely cures, the problem. Because the physician's primary goal is to relieve symptoms, it would appear that surgery benefited at least two thirds of the patients. The statement that at 4.8 years after surgery 44% of surgical patients were not working does not necessarily mean that surgery was ineffective. The reasons for not working are not given, but it is implied that failed TOS surgery is the reason. There may be many reasons for not working, in addition to failed TOS surgery. It is improvement in symptoms, not the ability to return to work, that is regarded as the criterion for successful surgery. The authors note that only 36.5% of the workers at 4.8 years after surgery claimed that their symptoms were improved by surgery, yet 73.7% would undergo surgery again? They state that they have no explanation for this discrepancy, but it suggests that their questionnaire was flawed. One explanation might lie in the fact that the majority of patients who develop work-related TOS have at least one other associated diagnosis that can produce similar symptoms, such as carpal or cuboid tunnel syndromes, shoulder pathology, or cervical spine disease. Treating the other conditions, along with TOS, is sometimes necessary to significantly improve symptoms. We concur with the authors' conclusion that surgery for TOS should be the last resort in therapy. All patients should be treated conservatively first. Only when conservative treatment fails and symptoms are disabling for work, recreation, or activities of daily living should surgery be considered. However, these data are not sufficient to justify a position that surgery for TOS is never justified in workers' compensation cases.
Proceedings of the National Academy of Sciences of the United States of America, Aug 22, 2005
Oral and Maxillofacial Surgery Clinics of North America, May 1, 1992
SUMMARY Microreconstructive inferior alveolar nerve surgery is indicated when there is pain, into... more SUMMARY Microreconstructive inferior alveolar nerve surgery is indicated when there is pain, intolerable anesthesia, or intolerable paresthesia due to a neuroma, compression, or transection. The decision to intervene surgically depends upon the diagnostic evaluation, progress of sensory recovery, and patient's desires and expectations of inferior alveolar nerve sensibility. In appropriately selected patients, microreconstructive surgery can predictably reduce pain and improve stimulus detection and protective reflexes; however, microreconstructive surgery is much less predictable in improving stimulus interpretation or perception. Microreconstructive inferior alveolar nerve surgery is a cascade of surgical steps. The surgeon proceeds to the next step in the cascade based upon the surgical findings and the sensory deficit. In the hands of an experienced microsurgeon, most inferior alveolar nerve injuries can be repaired transorally; however, the transcervical approach should be used if in the microsurgeon's judgment a better repair can be accomplished.
Nature Neuroscience, Sep 3, 2002
Acute deafferentation of a limb results in bilateral cortical reorganization, but the behavioral ... more Acute deafferentation of a limb results in bilateral cortical reorganization, but the behavioral consequences of this phenomenon are unknown. Here we found rapid improvements in tactile spatial acuity and changes in cortical processing for the left hand during cutaneous anesthesia of the right hand. The site-specific improvement in tactile spatial acuity may represent a behavioral compensatory gain.
Elsevier eBooks, 2003
Publisher Summary This chapter summarizes experiments showing that deprivation of somatosensory i... more Publisher Summary This chapter summarizes experiments showing that deprivation of somatosensory input could also elicit organizational changes in the hemisphere contralateral to the deafferented one. The existence of interactions among homotopic sites within cortical representations in both hemispheres provides a substrate for such an effect. It has been proposed that chronic deafferentation, in association with long-term practice as in blind, deaf, or individuals with amputation results in compensatory gains in the same and in other sensory modalities. However, the long-term changes described are mild and the question whether blind or deaf people develop enhanced capacities of their remaining senses is still controversial. Acute deafferentation leads to rapid changes of contra and ipsilateral cortical representations. Much less is known about the behavioral consequences of acute deafferentation in humans. It is conceivable that there are “built-in” mechanisms by which interruption of sensory input from one region leads to perceptual compensatory enhancements in a different site. An immediate behavioral improvement in a different body site or modality following acute deafferentation could reflect the existence of compensatory mechanisms to allow coping with the new deficit.
Journal of Neuroscience Methods, Sep 1, 2006
In order to expand the repertoire of somatosensory functions that can be effectively studied thro... more In order to expand the repertoire of somatosensory functions that can be effectively studied through functional MRI, we have developed a tactile stimulator which can deliver rich and varied combinations of stimulation that simulate natural tactile exploration. The system is computer controlled and compatible with an MRI environment. Complex aspects of somesthesis can thus be studied independent of confounds introduced by motor activity or problems with precision, accuracy or reproducibility of stimulus delivery.
Neurology, 2000
Background: In patients with focal hand dystonia, abnormal digit representations in the primary s... more Background: In patients with focal hand dystonia, abnormal digit representations in the primary somatosensory cortex (S1) could be the result of enlarged and overlapping receptor fields, as suggested by an animal model of dystonia. A possible clinical correlate of this S1 abnormality is a disturbed spatial discrimination capability. Objective: To test the hypothesis that somatosensory spatial discrimination is abnormal in focal hand dystonia. Methods: Seventeen patients with focal hand dystonia underwent a quantitative evaluation of somatosensory spatial frequency (gap detection, JVP domes, applied to the distal phalanx of the index finger) and single-touch localization (Von Frey monofilaments, applied to the middle phalanx of the index finger). Results: Compared with control subjects, patients had a decreased performance in both the gap detection (p ϭ 0.004) and the localization (p ϭ 0.013) tasks. The extent of spatial frequency abnormality correlated with age in both groups. Conclusions: These findings, together with a previously shown temporal discrimination deficit, support a role for sensory dysfunction in the pathophysiology of dystonia.
Neurology, 2001
line (RR 5 0.67, 95% CI 0.24, 1.89) relative to no selegiline in PD subjects. We agree, in genera... more line (RR 5 0.67, 95% CI 0.24, 1.89) relative to no selegiline in PD subjects. We agree, in general, that the RCT is the gold standard approach to efficacy. However, all studies are prone to bias, even RCTs. The major bias of RCTs is that they generally exclude a large proportion of subjects (very old, major comorbidity) who are exposed to these drugs. The UK-PDRG19 did recruit patients routinely but still had exclusions. In addition, approximately 50% switched treatment arm (with potential biases in an intention-totreat analysis). Finally, on-treatment analysis did not produce significant results,20 whereas the 21 months follow-up analysis also found a lower and nonsignificant adverse effect of selegiline.21 No study is perfect, even an RCT, and we should examine all the evidence,22 alongside the quality of design and analysis. Our main conclusion of no evidence of increase in mortality in patients with PD receiving selegiline is justified.
Proceedings of the National Academy of Sciences, 2005
To elucidate the neural basis of the recognition of tactile form and location, we used functional... more To elucidate the neural basis of the recognition of tactile form and location, we used functional MRI while subjects discriminated gratings delivered to the fingertip of either the right or left hand. Subjects were required to selectively attend to either grating orientation or grating location under identical stimulus conditions. Independent of the hand that was stimulated, grating orientation discrimination selectively activated the left intraparietal sulcus, whereas grating location discrimination selectively activated the right temporoparietal junction. Hence, hemispheric dominance appears to be an organizing principle for cortical processing of tactile form and location.
Nature Neuroscience, 2002
Acute deafferentation of a limb results in bilateral cortical reorganization, but the behavioral ... more Acute deafferentation of a limb results in bilateral cortical reorganization, but the behavioral consequences of this phenomenon are unknown. Here we found rapid improvements in tactile spatial acuity and changes in cortical processing for the left hand during cutaneous anesthesia of the right hand. The site-specific improvement in tactile spatial acuity may represent a behavioral compensatory gain.
Brain, 1994
Twenty-four subjects were studied before and up to 1 year after surgery that produced injury to a... more Twenty-four subjects were studied before and up to 1 year after surgery that produced injury to a major sensory branch of the trigeminal nerve. We employed a battery of 11 psychophysical tests, in which the neural mechanisms underlying performance are understood, to study the basis of recovery following nerve injury. Immediately after nerve injury, sensation was profoundly impaired in all subjects. In the following weeks and months, the recovery of performance proceeded in an orderly fashion. Although the rates of recovery varied between subjects, the order of recovery between tasks did not. The recovery rates fell into three distinct categories. Recovery in one task, brush-stroke directional discrimination, was most rapid. Two weeks after nerve injury, 52% of subjects could discriminate brush-stroke direction; by 3 months only one subject could not perform this task. The second category comprised recovery rates for pain thresholds for noxious heat, cold and mechanical stimuli, and to preinjury performance in tasks assessing touch and vibration detection, two-point discrimination, cooling detection and subjective magnitude estimation of mechanical force. The third, slowest group included recovery rates for warming detection and grating orientation discrimination. Early recovery to preinjury performance levels in the brush-stroke direction and one-point versus two-point discrimination tasks was correlated with later recovery to near normal performance in the grating orientation task. The grating orientation task was unique in providing a measure that corresponded consistently with the subjects' reports of sensory deficits. Our psychophysical findings are consistent with neurophysiological data showing that the major primary afferent fibre classes reinnervate the skin at a similar rate. A hypothesis that accounts for the psychophysical findings in this study is that differences in recovery rates between tasks is determined largely by their relative dependencies on functional innervation density. Alternative hypotheses are considered.
The Journal of Rehabilitation Research and Development, 2009
Texas medicine, Oct 1, 2018
Fear remains a major barrier to transparency of hospital errors.
Supplements to Clinical Neurophysiology, 2003
... 56) Chapter 24 Bihemispheric plasticity after acute hand deafferentation Konrad 1. Werhahn&am... more ... 56) Chapter 24 Bihemispheric plasticity after acute hand deafferentation Konrad 1. Werhahn", Jennifer Mortensen", Robert W. Van Boven-and Leonardo G ... reliance on the remaining senses like in blind (Van Boven et al., 2000) or deaf subjects (Neville and Lawson, 1987), the ...
A psychophysical study of the mechanisms of sensory recovery following nerve injury in humans
Fear remains a major barrier to transparency of hospital errors.
Oral and Maxillofacial Surgery Clinics of North America
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Papers by Robert Van Boven