D Berckmans

Publications (6)4.13 Total impact

• Article: Unobtrusive assessment of motor patterns during sleep based on mattress indentation measurements.

  Vincent Verhaert, Bart Haex, Tom De Wilde, Daniel Berckmans, Marie Vandekerckhove, Johan Verbraecken, Jos Vander Sloten
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  ABSTRACT: This study investigates how integrated bed measurements can be used to assess motor patterns (movements and postures) during sleep. An algorithm has been developed that detects movements based on the time derivate of mattress surface indentation. After each movement, the algorithm recognizes the adopted sleep posture based on an image feature vector and an optimal separating hyperplane constructed with the theory of support vector machines. The developed algorithm has been tested on a dataset of 30 fully recorded nights in a sleep laboratory. Movement detection has been compared to actigraphy, whereas posture recognition has been validated with a manual posture scoring based on video frames and chest orientation. Results show a high sensitivity for movement detection (91.2%) and posture recognition (between 83.6% and 95.9%), indicating that mattress indentation provides an accurate and unobtrusive measure to assess motor patterns during sleep.
  IEEE transactions on information technology in biomedicine: a publication of the IEEE Engineering in Medicine and Biology Society 03/2011; 15(5):787-94. · 1.69 Impact Factor
• Article: A new test set-up for skull fracture characterisation.

  P Verschueren, H Delye, B Depreitere, C Van Lierde, B Haex, D Berckmans, I Verpoest, J Goffin, J Vander Sloten, G Van der Perre
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  ABSTRACT: Skull fracture is a frequently observed type of severe head injury. Historically, a variety of impact test set-ups and techniques have been used for investigating skull fracture. The most frequently used are the free-fall technique, the guided fall or drop tower set-up and the piston-driven impactor set-up. This document proposes a new type of set-up for cadaver head impact testing which combines the strengths of the most frequently used techniques and devices. The set-up consists of two pendulums, which allow for a 1 degree of freedom rotational motion. The first pendulum is the impactor and is used to strike the blow. The head is attached to the second pendulum using a polyester resin. Local skull deformation and impact force are measured with a sample frequency of 65 kHz. From these data, absorbed energy until skull fracture is calculated. A set-up evaluation consisting of 14 frontal skull and head impact tests shows an accurate measurement of both force and local skull deformation until fracture of the skull. Simplified mechanical models are used to analyse the different impacting techniques from literature as well as the new proposed set-up. It is concluded that the proposed test set-up is able to accurately calculate the energy absorbed by the skull until fracture with an uncertainty interval of 10%. Second, it is concluded that skull fracture caused by blunt impact occurs before any significant motion of the head. The two-pendulum set-up is the first head impact device to allow a well-controlled measurement environment without altering the skull stress distribution.
  Journal of Biomechanics 02/2007; 40(15):3389-96. · 2.43 Impact Factor
• Chapter: Cerebral Bridging Vein Rupture in Humans: An Experimental Evaluation

  Bart Depreitere, C. Van Lierde, P. Verschueren, H. Delye, D. Berckmans, I. Verpoest, J. Vander Sloten, G. Van der Perre, J. Goffin
  01/2005: pages 305-12;
• Chapter: Cerebral Bridging Vein Rupture in Humans

  B. Depreitere, C. Van Lierde, P. Verschueren, H. Delye, D. Berckmans, I. Verpoest, J. Vander Sloten, G. Van der Perre, J. Goffin
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  ABSTRACT: A well known cause of death and disability after head trauma is the occurrence of an acute subdural haematoma (ASDH) due to bridging vein rupture. In the past, damage to the bridging veins and ASDH has been shown to be related to angular acceleration of the head in the sagittal plane. The objective of the present study was to establish critical peak angular accelerations in short duration impacts on the head (<15ms), typical for falls and collisions. 18 tests were performed. The results complement impact data from Löwenhielm. Moreover, the tolerance criteria for bridging vein disruption suggested by Löwenhielm are confirmed for short pulse durations. The first states that the peak angular acceleration cannot exceed 4500 rad/s?. The second constitutes a limitation of the change in angular velocity to 40 rad/s. If both of these conditions are fulfilled, the integrity of the bridging veins is said to be assured.
  12/2004: pages 305-312;
• Chapter: Biomechanics of Frontal Skull Fracture

  H. Delye, P. Verschueren, B. Depreitere, C. Van Lierde, I. Verpoest, D. Berckmans, J. Vander Sloten, G. Van der Perre, J. Goffin
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  ABSTRACT: The main purpose of the present study was to investigate whether an energy failure level would apply to the skull fracture mechanics in unembalmed post mortem human heads under dynamic frontal loading conditions. A double-pendulum set-up was used to conduct frontal impact tests on specimens from eight unembalmed post mortem human subjects. The specimens were isolated at the occipital condyle level and pre-test computed tomography images were obtained. The specimens were rigidly attached to an aluminum pendulum in an upside down position and obtained a single degree of freedom, allowing motion in the plane of impact. A steel pendulum delivered the impact and was fitted with a flat-surfaced, cylindrical aluminum impactor, which distributed the load to a force sensor. The relative displacement between the two pendulums was measured using a laser sensor and used as a measure for the deformation of the specimen in the plane of impact. Two impact velocity conditions were created: low (3.60±0.24 m/s) or high (5.18±0.04m/s) velocity. Computed tomography and dissection techniques were used to detect pathology. If no fracture was detected, repeated tests on the same specimen were performed with higher impact energy until fracture occurred. Eventually all specimens were fractured. Peak force, displacement and energy variables were used to describe the biomechanics. These preliminary data suggest a positive correlation between impact velocity and energy to fracture. Further experiments are necessary to elucidate the possibility of an energy criterion for skull fracture in head impacts.
  12/2004: pages 185-193;
• Chapter: Clinical and Biomechanical Research for Bicycle Helmet Optimisation

  C. Van Lierde, B. Depreitere, P. Verschueren, H. Delye, D. Berckmans, I. Verpoest, J Goffin, J. Vander Sloten, G. Van der Perre
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  ABSTRACT: Epidemiological studies on bicycle accidents show that a substantial fraction of the cyclists that call for medical aid, are suffering from skull and brain damage. The aim of the research performed at the K.U.Leuven is to reduce the risk of serious head injuries by the creation of a new type of bicycle helmet. To achieve this goal, a clinical review of pedal cyclist head lesions has been performed, a 3D accident simulation program has been developed, skull behaviour during impact testing has been studied and the current protective effect of a typical series of bicycle helmet has been evaluated. The absence of a temple cover allows a potentially dangerous contact between the temple of the head and the impact surface [1].
  12/2004: pages 247-254;