Malgorzata Gawel

The value of quantitative EEG in differential diagnosis of Alzheimer's disease and subcortical vascular dementia

OBJECTIVE To investigate whether quantitative EEG may be useful in differential diagnosis of AD and SVD and to determine the correlation between dementia and abnormalities in EEG. MATERIALS AND METHODS The group under study was consisted of 62 patients with AD (mean age: 73.6 yrs; M 51%), 31 with SVD (mean age: 75.2 yrs, M 43%) and a control group of 14 healthy subjects (mean age: 69.5 yrs, M 43%). The patients were divided into subgroups of those with mild, moderate and marked dementia. EEG findings were classified using eight-degree scale according to the presence of slow waves, and then quantitative analysis was carried out by calculating the alpha/slow wave power ratios and the mean frequencies in all and some selected derivations. RESULTS A significant difference between visual EEGs and QEEGs in AD and SVD was found. Only QEEG parameters differed in AD and SVD subgroups with the same degree of cognitive impairment: the mean wave frequencies of waves in temporal derivations in subgroups with mild and moderate dementia and alpha/delta waves power ratio in subgroups with moderate dementia. CONCLUSIONS Visual EEGs and QEEGs could be used in addition to the differential diagnosis between AD and SVD, but only selected parameters of QEEG could be useful in differentiating between AD and SVD subgroups with the same degree of dementia.

Quality Control of Motor Unit Number Index (MUNIX) Measurements in 6 Muscles in a Single-Subject “Round-Robin” Setup

Background Motor Unit Number Index (MUNIX) is a neurophysiological measure that provides an index of the number of lower motor neurons in a muscle. Its performance across centres in healthy subjects and patients with Amyotrophic Lateral Sclerosis (ALS) has been established, but inter-rater variability between multiple raters in one single subject has not been investigated. Objective To assess reliability in a set of 6 muscles in a single subject among 12 examiners (6 experienced with MUNIX, 6 less experienced) and to determine variables associated with variability of measurements. Methods Twelve raters applied MUNIX in six different muscles (abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibialis anterior (TA), extensor dig. brevis (EDB), abductor hallucis (AH)) twice in one single volunteer on consecutive days. All raters visited at least one training course prior to measurements. Intra- and inter-rater variability as determined by the coefficient of variation (COV) between different raters and their levels of experience with MUNIX were compared. Results Mean intra-rater COV of MUNIX was 14.0% (±6.4) ranging from 5.8 (APB) to 30.3% (EDB). Mean inter-rater COV was 18.1 (±5.4) ranging from 8.0 (BB) to 31.7 (AH). No significant differences of variability between experienced and less experienced raters were detected. Conclusion We provide evidence that quality control for neurophysiological methods can be performed with similar standards as in laboratory medicine. Intra- and inter-rater variability of MUNIX is muscle-dependent and mainly below 20%. Experienced neurophysiologists can easily adopt MUNIX and adequate teaching ensures reliable utilization of this method.

Does EEG (visual and quantitative) reflect mental impairment in subcortical vascular dementia

UNLABELLED The aim of this study was to determine if the results of visual and quantitative EEG (QEEG) parameters reveal a correlation with mental impairment in subcortical vascular dementia (SVD), one of the most frequent causes of cognitive impairment in the elderly. In SVD, like in Alzheimers disease disturbances were found in cholinergic transmission. The cholinergic deficit as manifested in changes of synaptic potentials is reflected in EEG signals. MATERIAL 31 patients with probable SVD (according to NINCDS-AIREN and T. Erkinjuntiis criteria) and mean age 72.3 yrs;(M--43%, F--57%) and 14 healthy control subjects with mean age of 72.3 yrs (M-57%, F-43%). According to the Mini Mental Scale Examination (MMSE) the SVD group was divided into two subgroups with mild and moderate dementia, their EEGs being recorded with a Medelec and Neuroscan 4.2 system. Visual EEG findings were classified with the use of eight-degree scale of pathological changes by the presence of slow waves. Then QEEGs were made. The following parameters were calculated: alpha/slow wave power ratios, the mean wave frequency in all and in some selected derivations. RESULTS A significant difference was found between QEEGs in SVD subgroups with mild and moderate dementia (p<0.05), but there was no significant difference between visual EEGs. A significant correlation between QEEG parameters such as alpha/slow wave ratio or mean wave frequency and mental impairment (according to MMSE results) was found (p<0.001), but there was no significant correlation between degree of EEG abnormalities in visual analysis and MMSE results. CONCLUSION Only QEEGs are correlated with mental impairment in SVD. Visual EEG technique as a less precise tool does not reflect the mental impairment in SVD due to cholinergic deficit.

Effect of age and gender on the number of motor units in healthy subjects estimated by the multipoint incremental MUNE method.

Purpose: Motor unit number estimation (MUNE) is a tool for estimating the number of motor units. The aim was to evaluate the multipoint incremental MUNE method in a healthy population, to analyze whether aging, gender, and the dominant hand side influence the motor unit number, and to assess reproducibility of MUNE with the Shefner modification. Materials and Methods: We studied 60 volunteers (mean age, 47 ± 17.7 years) in four groups aged 18 to 30, 31 to 45, 46 to 60, and above 60 years. Motor unit number estimation was calculated in the abductor pollicis brevis (APB) and the abductor digiti minimi (ADM) by dividing the single motor unit action potential amplitude into the maximal compound motor action potential amplitude. Results: Test–retest variability was 7%. The mean value of MUNE for APB was 133.2 ± 43 and for ADM was 157.1 ± 39.4. Significant differences in MUNE results were found between groups aged 18 to 30 and 60 years or older and between groups aged 31 to 45 and 60 years or older. Motor unit number estimation results correlated negatively with the age of subjects for both APB and ADM. Single motor unit action potential, reflecting the size of motor unit, increased with the age of subjects only in APB. Compound motor action potential amplitude correlated negatively with the age of subjects in APB and ADM. Significant correlations were seen between MUNE in APB or ADM and compound motor action potential amplitude in these muscles and the age of female subjects. A similar relationship was not found in males. Conclusions: Multipoint incremental MUNE method with the Shefner modification is a noninvasive, easy to perform method with high reproducibility. The loss of motor neurons because of aging could be confirmed by our MUNE study and seems to be more pronounced in females.

Are we really closer to improving the diagnostic sensitivity in ALS patients with Awaji criteria

Abstract The Awaji criteria, recently introduced to increase diagnosis sensitivity in amyotrophic lateral sclerosis (ALS), equate the diagnostic significance of neurogenic electrophysiological changes to clinical signs of lower motor neuron dysfunction. They also increase the electrophysiological significance of fasciculation potentials (FPs). The aim of our study was to analyse whether the new parameters improve diagnostic sensitivity in ALS patients primarily diagnosed with the El Escorial criteria. Medical and electrophysiological records of 135 consecutive patients with ALS and 25 patients with progressive muscular atrophy (PMA) who underwent electrophysiological examination of at least three anatomical regions were analysed retrospectively. Results showed that implementation of the Awaji criteria increased the level of ALS diagnosis sensitivity in 5.9% of cases – 1.5% due to the new role of FPs potentials and 4.4% because of equalization of clinical and EMG findings. In 4% of patients the ALS diagnosis was, however, changed from laboratory-supported probable ALS to possible ALS. In conclusion, our study confirms that Awaji modifications are able to improve the diagnostic certainty in a few ALS cases. Although the new approach to FPs markedly increases the number of involved muscles, it only slightly raises the number of involved regions.

Motor unit loss estimation by the multipoint incremental MUNE method in children with spinal muscular atrophy – A preliminary study

Quantitative EMG reflects denervation of muscles after lower motor neuron degeneration in spinal muscular atrophy (SMA) but does not reflect actual motor unit loss. The aim of our study was to assess the value of the multipoint incremental motor unit number estimation (MUNE) method in the modification by Shefner in estimating motor unit loss in SMA. The number of motor units, the mean amplitude of an average surface-detected single motor unit potential (SMUP), and the amplitude of compound motor action potentials (CMAP) were estimated in 14 children with SMA in the abductor pollicis brevis (ABP). Significant differences in MUNE values and SMUP and CMAP amplitude were found between the SMA and control groups (P < 0.0001). MUNE values correlated with Hammersmith Functional Motor Scale (HFMS) scores (P < 0.05). Increased SMUP amplitude values correlated with decreased HFMS scores (P < 0.05). The study confirms that MUNE method in the modification by Shefner is a useful tool reflecting motor unit loss in SMA, and it is easy to perform and well tolerated. MUNE and SMUP amplitude seemed to be sensitive parameters reflecting motor dysfunction in SMA but a longitudinal study in a larger number of subjects is needed.

Early-Onset Facioscapulohumeral Muscular Dystrophy Type 1 With Some Atypical Features

Facioscapulohumeral muscular dystrophy cases with facial weakness before the age of 5 and signs of shoulder weakness by the age of 10 are defined as early onset. Contraction of the D4Z4 repeat on chromosome 4q35 is causally related to facioscapulohumeral muscular dystrophy type 1, and the residual size of the D4Z4 repeat shows a roughly inverse correlation with the severity of the disease. Contraction of the D4Z4 repeat on chromosome 4q35 is believed to induce a local change in chromatin structure and consequent transcriptional deregulation of 4qter genes. We present early-onset cases in the Polish population that amounted to 21% of our total population with facioscapulohumeral muscular dystrophy. More than 27% of them presented with severe phenotypes (wheelchair dependency). The residual D4Z4 repeat sizes ranged from 1 to 4 units. In addition, even within early-onset facioscapulohumeral muscular dystrophy type 1 phenotypes, some cases had uncommon features (head drop, early disabling contractures, progressive ptosis, and respiratory insufficiency and cardiomyopathy).

Carpal Tunnel Syndrome in Children

Carpal tunnel syndrome rarely occurs in children. We retrospectively analyzed clinical data of 11 patients aged 5-17 diagnosed with carpal tunnel syndrome at a single pediatric neuromuscular center. Nerve conduction studies were performed according to the American Association of Electrodiagnostic Medicine recommendations. Additional imaging tests of the wrist were performed in 10 patients. In our group of 11 children, carpal tunnel syndrome was idiopathic in only 1 case. In the remaining subjects, it was secondary to congenital bone anomaly (6), hypothyroidism (2), or myopathic contractures (1). In 1 case, metabolic workup revealed an underlying mucopolysaccharidosis. Our results confirm that idiopathic carpal tunnel syndrome is rare in children. Hand clumsiness and thenar hypoplasia rather than sensory complaints are the presenting symptoms. Whenever carpal tunnel syndrome is diagnosed in a child, a thorough differential diagnosis should be made because of the secondary nature of this disease in most pediatric patients.

Motor unit number estimation as a complementary test to routine electromyography in the diagnosis of amyotrophic lateral sclerosis

Electromyographic (EMG) abnormalities that reveal denervation and reinnervation caused by lower motor neuron degeneration do not reflect the number of motor units that determines muscle strength. Consequently, motor unit activity potential (MUAP) parameters do not reflect muscle dysfunction. The aim of the study was to compare the value of motor unit number estimation (MUNE) and MUAP parameters as indicators of clinical muscle dysfunction in patients with amyotrophic lateral sclerosis (ALS), and to analyze the role of MUNE as a supplement to the EMG criteria for the diagnosis of ALS. In 25 patients with ALS, MUNE by the multipoint incremental method in the abductor digiti minimi (ADM) and quantitative EMG in the first dorsal interosseous (FDI) were obtained. The Medical Research Council (MRC) scale was used to evaluate clinical muscle dysfunction. A strong correlation between the number of motor units evaluated by MUNE and ADM clinical function by the MRC scale was found (P<0.001). An increased value of surface-detected single motor action potential was associated with a decreased MRC score for ADM (P<0.1). No relation was found between MUAP parameters in FDI and MRC scores. Our data support the value of the MUNE method for the detection of motor unit loss in ALS, and it could be postulated that MUNE studies may be considered complementary tests for ALS in a future revision of ALS criteria.

Clinical and Functional Assessment of Dysautonomia and Its Correlation in Alzheimer’s Disease

The aims were to assess dysautonomia in Alzheimer’s Disease (AD), clinically and electrophysiologically, using sympathetic skin response (SSR) test and R-R interval variation (RRIV) test and to analyze the relationship between symptoms of dysautonomia and SSR/RRIV results. A tota of 54 patients with AD and 37 controls were evaluated using Autonomic Symptoms Questionnaire and SSR/RRIV test. Clinical dysautonomia was observed in 66% of patients (eg, orthostatic hypotension in 34.5%, constipation in 17.2%, urinary incontinence in 13.8%). The SSR test was abnormal in 26%, but the RRIV test was abnormal in 97.7% of cases; there was significant difference in RRIV test results between AD and controls (R mean 8.05% and 14.6%, respectively). In AD, clinical dysautonomia occurs at a various degree, and the abnormal SSR and RRIV test results were not always related to the presence of clinical dysautonomia; this observation points that the tests could be used as a useful tool in the assessment of subclinical dysautonomia.