For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to de... more For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examin...
Today, treatment of the nondystrophic myotonias consists of mexiletine, although care has to be t... more Today, treatment of the nondystrophic myotonias consists of mexiletine, although care has to be taken because of the proarrhythmogenic potential of this drug. In this article, we report years of experience with the carbonic anhydrase inhibitor acetazolamide. We present three children with nondystrophic myotonias. During acetazolamide treatment, symptoms and signs of myotonia decreased in our children. Based on this clinical experience and the favorable pharmacologic profile of acetazolamide, it may be a good treatment option for children with nondystrophic myotonias.
We report on a 16-year-old Dutch patient in whom rippling muscle disease (RMD) was diagnosed year... more We report on a 16-year-old Dutch patient in whom rippling muscle disease (RMD) was diagnosed years after his mother had been falsely diagnosed with acid maltase deficiency. The autosomal dominant mode of inheritance of the neuromuscular symptoms in this family had led to a re-evaluation of the diagnosis of acid maltase deficiency. Physical examination revealed the three key features leading to the clinical diagnosis of RMD: rippling, mounding, and percussion-induced rapid muscle contraction. Mutation analysis revealed a novel heterozygous missense mutation in the caveolin-3 gene (c.79C > G; p.Arg27Gly) in both the index patient and his mother. This case report stresses the importance of adhering to the mode of inheritance in the diagnosis of neuromuscular disorders. It also indicates that typical RMD phenomena are not easily acknowledged among paediatricians or neurologists. We therefore present an overview of these clinical characteristics of rippling muscle disease RMD.
... Harper 2004; Steinert 1910). Esta enfermedad es causada por la expansión de la repetición del... more ... Harper 2004; Steinert 1910). Esta enfermedad es causada por la expansión de la repetición del trinucleótido CTG (citosina-timina-guanina) en el gen DMPK en el cromosoma 19q (Brook 1992; Harley 1992). La herencia se ...
To assess whether shared medical appointments (SMAs) for neuromuscular patients represent a way o... more To assess whether shared medical appointments (SMAs) for neuromuscular patients represent a way of using clinicians' time efficiently without compromising quality of care for patients. Patients with a chronic neuromuscular disease (NMD) (n = 272) were randomly allocated to either an SMA or a regular individual annual appointment and followed up for a period of 6 months. Data on resource utilization and quality of life (EQ-5D) were collected prospectively, using a health care perspective. Incremental costs and changes in quality-adjusted life-years (QALYs) were computed using a probabilistic decision model. Factors critical to the incremental cost-effectiveness of SMAs were explored in sensitivity analyses. No substantial differences between SMAs and individual visits in terms of costs per QALY were found (incremental cost-effectiveness ratio €-960.00; 95% confidence interval €-34,600.00, €+36,800.00). Sensitivity analyses showed that the cost-effectiveness ratio was particularly...
Patients with non-dystrophic myotonias, including chloride (myotonia congenita) and sodium channe... more Patients with non-dystrophic myotonias, including chloride (myotonia congenita) and sodium channelopathies (paramyotonia congenita/potassium aggravated myotonias), may show muscular hypertrophy in combination with some histopathological abnormalities. However, the extent of muscle changes has never been assessed objectively in a large group genetically confirmed patients. This study quantitatively determines echo intensities, thicknesses, ranges-of-motion and force of four skeletal muscles in 63 genetically confirmed patients. The main findings revealed elevated echo intensities in all muscles except the rectus femoris (+1.3-2.2SD, p<0.0001), and hypertrophy in the arms (+0.5-0.9SD, p<0.01). Muscle echo intensities were inversely correlated to the corresponding ranges-of-motion (biceps brachii: r= -0.43; p<0.001, forearm flexors: r= -0.47; p<0.001, rectus femoris: r= -0.40; p=0.001, and tibial anterior: r= -0.27; p=0.04) and correlated positively to age (r=0.22; p=0.05)....
Various ancillary investigations can assist clinicians in the differential diagnosis of patients ... more Various ancillary investigations can assist clinicians in the differential diagnosis of patients with parkinsonism. It is unknown which test offers greatest diagnostic value in clinical practice. We included 156 consecutive patients with parkinsonism, but with an initially uncertain diagnosis. At baseline, all patients underwent extensive clinical testing and the following ancillary investigations: brain magnetic resonance imaging (MRI); (123)I-iodobenzamide single photon-emission computed tomography (IBZM-SPECT); analysis of cerebrospinal fluid (CSF); and anal sphincter electromyography (EMG). The final diagnosis was established after 3-year follow-up by two movement disorder specialists, according to international consensus criteria. We determined the diagnostic value by comparing the baseline clinical parameters and ancillary studies with the final diagnosis. Out of a potential 138 parameters, univariate analysis identified 35 parameters that discriminated Parkinson's disease...
To systematically study the effects of shared medical appointments (SMAs) compared with individua... more To systematically study the effects of shared medical appointments (SMAs) compared with individual appointments for patients with a chronic neuromuscular disorder and their partners. In this randomized controlled trial with a follow-up of 6 months, we included patients with a chronic neuromuscular disorder and their partners. Participants were randomly allocated to an SMA or an individual outpatient appointment. The primary outcome measure was patients' health-related quality of life (QOL) (36-Item Short Form Health Survey). Secondary outcome measures included self-efficacy, social support, patient and partner satisfaction with the appointment, and time available per patient. Two hundred seventy-two patients and 149 partners were included. Health-related QOL showed greater improvement in patients who had attended an SMA (mean difference 2.8 points, 95% confidence interval 0.0-5.7, p = 0.05). Secondary outcomes showed small improvements in the control group for satisfaction with ...
Nederlands tijdschrift voor geneeskunde, Jan 17, 2005
Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is... more Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is responsible for the symptoms. They manifest as diseases of the heart, brain or skeletal muscle. Hereditary skeletal-muscle channelopathies are characterised by myotonia, periodic paralysis or a combination of both and can be categorised as chloride, sodium and calcium channelopathies. When there is myotonia, the skeletal-muscle membrane is overexcited. In cases of periodic paralysis, the skeletal-muscle membrane is inactive. It is difficult to classify hereditary muscle channelopathies on the basis of clinical criteria only. A more reliable diagnosis is made using DNA analysis. Scientific research should focus on genotype-phenotype relationships.
Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is... more Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is responsible for the symptoms. They manifest as diseases of the heart, brain or skeletal muscle. Hereditary skeletal-muscle channelopathies are characterised by myotonia, periodic paralysis or a combination of both and can be categorised as chloride, sodium and calcium channelopathies. When there is myotonia, the skeletal-muscle
BACKGROUND: Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disabil... more BACKGROUND: Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disability in myotonic disorders. Sodium channel blockers, tricyclic antidepressive drugs, benzodiazepines, calcium-antagonists, taurine and prednisone may be of use in reducing myotonia. OBJECTIVES: To consider the evidence from randomised controlled trials on the efficacy and tolerability of drug treatment in patients with clinical myotonia due to a myotonic
For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to de... more For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examin...
Today, treatment of the nondystrophic myotonias consists of mexiletine, although care has to be t... more Today, treatment of the nondystrophic myotonias consists of mexiletine, although care has to be taken because of the proarrhythmogenic potential of this drug. In this article, we report years of experience with the carbonic anhydrase inhibitor acetazolamide. We present three children with nondystrophic myotonias. During acetazolamide treatment, symptoms and signs of myotonia decreased in our children. Based on this clinical experience and the favorable pharmacologic profile of acetazolamide, it may be a good treatment option for children with nondystrophic myotonias.
We report on a 16-year-old Dutch patient in whom rippling muscle disease (RMD) was diagnosed year... more We report on a 16-year-old Dutch patient in whom rippling muscle disease (RMD) was diagnosed years after his mother had been falsely diagnosed with acid maltase deficiency. The autosomal dominant mode of inheritance of the neuromuscular symptoms in this family had led to a re-evaluation of the diagnosis of acid maltase deficiency. Physical examination revealed the three key features leading to the clinical diagnosis of RMD: rippling, mounding, and percussion-induced rapid muscle contraction. Mutation analysis revealed a novel heterozygous missense mutation in the caveolin-3 gene (c.79C &amp;amp;gt; G; p.Arg27Gly) in both the index patient and his mother. This case report stresses the importance of adhering to the mode of inheritance in the diagnosis of neuromuscular disorders. It also indicates that typical RMD phenomena are not easily acknowledged among paediatricians or neurologists. We therefore present an overview of these clinical characteristics of rippling muscle disease RMD.
... Harper 2004; Steinert 1910). Esta enfermedad es causada por la expansión de la repetición del... more ... Harper 2004; Steinert 1910). Esta enfermedad es causada por la expansión de la repetición del trinucleótido CTG (citosina-timina-guanina) en el gen DMPK en el cromosoma 19q (Brook 1992; Harley 1992). La herencia se ...
To assess whether shared medical appointments (SMAs) for neuromuscular patients represent a way o... more To assess whether shared medical appointments (SMAs) for neuromuscular patients represent a way of using clinicians' time efficiently without compromising quality of care for patients. Patients with a chronic neuromuscular disease (NMD) (n = 272) were randomly allocated to either an SMA or a regular individual annual appointment and followed up for a period of 6 months. Data on resource utilization and quality of life (EQ-5D) were collected prospectively, using a health care perspective. Incremental costs and changes in quality-adjusted life-years (QALYs) were computed using a probabilistic decision model. Factors critical to the incremental cost-effectiveness of SMAs were explored in sensitivity analyses. No substantial differences between SMAs and individual visits in terms of costs per QALY were found (incremental cost-effectiveness ratio €-960.00; 95% confidence interval €-34,600.00, €+36,800.00). Sensitivity analyses showed that the cost-effectiveness ratio was particularly...
Patients with non-dystrophic myotonias, including chloride (myotonia congenita) and sodium channe... more Patients with non-dystrophic myotonias, including chloride (myotonia congenita) and sodium channelopathies (paramyotonia congenita/potassium aggravated myotonias), may show muscular hypertrophy in combination with some histopathological abnormalities. However, the extent of muscle changes has never been assessed objectively in a large group genetically confirmed patients. This study quantitatively determines echo intensities, thicknesses, ranges-of-motion and force of four skeletal muscles in 63 genetically confirmed patients. The main findings revealed elevated echo intensities in all muscles except the rectus femoris (+1.3-2.2SD, p<0.0001), and hypertrophy in the arms (+0.5-0.9SD, p<0.01). Muscle echo intensities were inversely correlated to the corresponding ranges-of-motion (biceps brachii: r= -0.43; p<0.001, forearm flexors: r= -0.47; p<0.001, rectus femoris: r= -0.40; p=0.001, and tibial anterior: r= -0.27; p=0.04) and correlated positively to age (r=0.22; p=0.05)....
Various ancillary investigations can assist clinicians in the differential diagnosis of patients ... more Various ancillary investigations can assist clinicians in the differential diagnosis of patients with parkinsonism. It is unknown which test offers greatest diagnostic value in clinical practice. We included 156 consecutive patients with parkinsonism, but with an initially uncertain diagnosis. At baseline, all patients underwent extensive clinical testing and the following ancillary investigations: brain magnetic resonance imaging (MRI); (123)I-iodobenzamide single photon-emission computed tomography (IBZM-SPECT); analysis of cerebrospinal fluid (CSF); and anal sphincter electromyography (EMG). The final diagnosis was established after 3-year follow-up by two movement disorder specialists, according to international consensus criteria. We determined the diagnostic value by comparing the baseline clinical parameters and ancillary studies with the final diagnosis. Out of a potential 138 parameters, univariate analysis identified 35 parameters that discriminated Parkinson's disease...
To systematically study the effects of shared medical appointments (SMAs) compared with individua... more To systematically study the effects of shared medical appointments (SMAs) compared with individual appointments for patients with a chronic neuromuscular disorder and their partners. In this randomized controlled trial with a follow-up of 6 months, we included patients with a chronic neuromuscular disorder and their partners. Participants were randomly allocated to an SMA or an individual outpatient appointment. The primary outcome measure was patients' health-related quality of life (QOL) (36-Item Short Form Health Survey). Secondary outcome measures included self-efficacy, social support, patient and partner satisfaction with the appointment, and time available per patient. Two hundred seventy-two patients and 149 partners were included. Health-related QOL showed greater improvement in patients who had attended an SMA (mean difference 2.8 points, 95% confidence interval 0.0-5.7, p = 0.05). Secondary outcomes showed small improvements in the control group for satisfaction with ...
Nederlands tijdschrift voor geneeskunde, Jan 17, 2005
Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is... more Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is responsible for the symptoms. They manifest as diseases of the heart, brain or skeletal muscle. Hereditary skeletal-muscle channelopathies are characterised by myotonia, periodic paralysis or a combination of both and can be categorised as chloride, sodium and calcium channelopathies. When there is myotonia, the skeletal-muscle membrane is overexcited. In cases of periodic paralysis, the skeletal-muscle membrane is inactive. It is difficult to classify hereditary muscle channelopathies on the basis of clinical criteria only. A more reliable diagnosis is made using DNA analysis. Scientific research should focus on genotype-phenotype relationships.
Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is... more Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is responsible for the symptoms. They manifest as diseases of the heart, brain or skeletal muscle. Hereditary skeletal-muscle channelopathies are characterised by myotonia, periodic paralysis or a combination of both and can be categorised as chloride, sodium and calcium channelopathies. When there is myotonia, the skeletal-muscle
BACKGROUND: Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disabil... more BACKGROUND: Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disability in myotonic disorders. Sodium channel blockers, tricyclic antidepressive drugs, benzodiazepines, calcium-antagonists, taurine and prednisone may be of use in reducing myotonia. OBJECTIVES: To consider the evidence from randomised controlled trials on the efficacy and tolerability of drug treatment in patients with clinical myotonia due to a myotonic
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