Motor unit firing in amyotrophic lateral sclerosis and other upper and lower motor neurone disorders

Objective

Motor unit recruitment order and firing rate was investigated in healthy subjects, and in small numbers of patients 50 years ago. We aimed to investigate firing rate in different disorders, testing the same target muscle with normal strength, to evaluate possible application in diagnosing upper motor neuron (UMN) lesion.

Methods

We studied motor unit firing in the tibialis anterior muscle in six groups of subjects; normal subjects (n = 45), patients with amyotrophic lateral sclerosis (ALS) (n = 36), primary lateral sclerosis (PLS) (n = 21), progressive muscular atrophy (PMA) (n = 14), various upper motor neurone lesions (n = 16) and polyneuropathy (n = 42). In all these subjects the tibialis anterior muscle was of normal strength. Motor units were recruited during slight contraction in order to study 2–5 motor units at each recording site, using a standard concentric needle electrode, so that 20–22 motor units were recorded in each muscle. We analysed the coefficient of variation (CV) for amplitude, area, duration and firing rate in these motor units, and the correlation between motor unit potential size and recruitment order.

Results

The mean MU firing rate in this task was similar in each group. No recruitment order was disclosed within the limits of the study task. The CV of firing rate was decreased in UMN and PLS groups. ALS patients with marked spasticity showed a lower CV of motor unit firing rate. The CV of amplitude, area and duration was similar between groups.

Conclusions

These results in tibialis anterior indicate that physiological modulation of lower motor neuron (LMN) firing rate is decreased in patients with lower limb spasticity. The variability of MU discharges tends to be greater in diseases affecting the LMN.

Significance

These results suggest that, notwithstanding the simplicity of the task we have used, the physiological variability of motor unit firing may be a useful variable in assessing UMN involvement in motor system disorders.     

Bandpass filter settings differentially affect measurement of P50 sensory gating in children and adults

Objective

This study investigated the effect of four different bandpass filter settings on measures of the P50 component and the signal-to-noise ratios (SNR) of averaged ERPs obtained from a sensory gating paradigm employing paired-click stimuli.

Methods

Participants were adults (n = 18) 20–55 years old and children (n = 25) 5–10 years old who were free of neurological disorders.

Results

Results show that the filter settings (0.23–75 Hz, 10–50 Hz, 10–75 Hz, and 10–200 Hz) differentially affected the P50 amplitude, noise power and SNR measures of the conditioning and test clicks, and P50 T/C ratios.

Conclusions

The 10–50 Hz filter setting may be optimal in studies that include only adults as these settings resulted in the smallest mean P50 T/C ratio, a reasonable standard deviation (SD) for the ratio, and the highest SNRs. The 10–200 Hz filter may be the best for studying young children as this setting had the smallest mean and SD of P50 T/C ratios for these participants.

Significance

In studies that include both adults and children investigators are advised to use the 10–200 Hz filter setting because the smaller variability of sensory gating in the child group helps ensure better homogeneity of variance measures between the groups.     

Short latency afferent inhibition associated with cortical compression and memory impairment in patients with chronic subdural hematoma

Objective

To evaluate the cortical excitability in patients with mild cortical compression.

Methods

The present study used short interval intracortical inhibition (SICI), intracortical facilitation (ICF), and short latency afferent inhibition (SAI) to evaluate motor cortex excitability in 16 chronic subdural hematoma (CSDH) patients with memory impairment and compared the data with those of 16 healthy controls.

Results

SAI was reduced in patients compared with controls (99 ± 14 vs. 47 ± 11% of the test size; p < 0.0001, unpaired t-test). CSDH patients tended to have a high resting motor threshold and less pronounced SICI and ICF than controls, but these differences were not significant. Treatment of hematoma improved memory impairment and SAI in CSDH patients with wide individual variations that ranged from an increase of 74% to 17% of test size.

Conclusion

These findings suggest that measuring SAI may provide a means of probing the integrity of cortical cholinergic networks in a compressed human brain.     

Measures of small-fiber neuropathy in HIV infection

Introduction

Noninvasive methods are needed to detect distal sensory polyneuropathy in HIV-infected persons on antiretroviral therapy (ART).

Methods

Quantitative sudomotor axon reflex test (QSART) and Utah Early Neuropathy Scale (UENS), small-fiber sensitive measures, were assessed in subjects with and without clinical neuropathy. Pain was assessed by visual analog scale (VAS).

Results

Twenty-two subjects had symptoms and signs of neuropathy, 19 had neither, and all were receiving ART. Median sweat volume (μL) was lower at all testing sites in those with neuropathy compared to those without (p < 0.01 for all). UENS and VAS (mm) were higher in neuropathy subjects (p < 0.05 for each). Lower sweat volume at all sites correlated with higher pin UENS subscore, total UENS, and VAS (p < 0.05 for all). In multivariable analyses adjusting for age, CD4⁺ T cells, sex, and use of “d-drug” ART, QSART and UENS remained associated (p = 0.003).

Conclusion

QSART and UENS have not been previously studied in this patient population and may identify small-fiber neuropathy in HIV-infected, ART-treated persons.     

How active are patients with idiopathic normal pressure hydrocephalus and does activity improve after shunt surgery? A controlled actigraphic study

Introduction

Actigraphy allows long-time evaluation of physical activity and resting behaviour in a normal environment. The aim of this study was, by use of actigraphy, to measure motor function, energy expenditure and resting/sleeping time in idiopathic normal pressure hydrocephalus (iNPH) patients before and after surgery, and compare the results with healthy individuals (HI).

Subjects and methods

33 patients (mean 73 year) and 17 HI (mean 73 year) participated. Actigraphy with SenseWear (BodyMedia Inc., Pittsburgh, PA, USA) was recorded in the iNPH patients before and three months postoperatively and twice in the HI with a three-month interval. In addition, gait speed, timed up and Go (TUG) and MMSE were registered pre- and post-operatively.

Results

During daytime the patients took fewer steps (p < 0.001) and their total energy expenditure (TEE) was lower (p < 0.01) than in the HI. Twenty patients were evaluated pre- and post-operatively and no change in either the number of steps, TEE, or time spent lying/sleeping after surgery could be detected. iNPH patients had lower gait speed, worse TUG and MMSE compared to the HI. Gait and TUG improved after surgery.

Conclusion

Actigraphy in iNPH patients indicated reduced ambulatory activity and lower energy expenditure compared to HI preoperatively. This did not change postoperatively in spite of improved TUG and gait speed.     

A comparison of two different continuous theta burst stimulation paradigms applied to the human primary motor cortex

Objective

The application of repetitive transcranial magnetic stimulation (rTMS) in bursts at theta frequencies (TBS) may produce lasting neuroplastic changes in the human cortex. However, there exists high variability in subjects’ responses, possibly due to non-optimal stimulation characteristics. Here we compare the efficacy of two variations of continuous TBS (cTBS) for producing neuroplastic change in the human primary motor cortex (M1).

Methods

The two cTBS paradigms were: (1) standard cTBS (cTBS_std) (three stimuli at 50 Hz, repeated at 5 Hz), and (2) modified cTBS (cTBS_mod) (three stimuli at 30 Hz, repeated at 6 Hz with intensity). Motor evoked potentials (MEPs) were recorded from the right first dorsal interosseous muscle before, as well as at 0, 5, 10, 20 and 30 min following each paradigm.

Results

Both cTBS_std (P = 0.05) and cTBS_mod (P < 0.0001) induced a suppression of MEP amplitudes. However, MEP suppression following cTBS_mod was greater (ANOVA_RM; P = 0.02). Experiments using magnetic brainstem stimulation provided evidence that cTBS_mod induced MEP suppression through cortical mechanisms.

Conclusions

The neuroplastic response of the human M1 to cTBS is highly dependent on the stimulation parameters employed.

Significance

These findings may have significant implications for the clinical application of cTBS paradigms.     

Factors affecting the diagnostic delay in amyotrophic lateral sclerosis

Background

Although amyotrophic lateral sclerosis (ALS) is a relentlessly progressive disorder, early diagnosis allows a prompt start with the specific drug riluzole and an accurate palliative care planning. ALS at onset may however mimic several disorders, some of them treatable (e.g., multifocal motor neuropathy) or epidemiologically more frequent (e.g., cervical myelopathy).

Objective

To study the delay from onset to diagnosis in a cohort of ALS patients and to the variables that may affect it.

Methods

We performed a retrospective analysis of the diagnostic delays in a cohort of 260 patients affected by ALS (M/F = 1.32) followed at our tertiary referral ALS Center between 2000 and 2007.

Results

The median time from onset to diagnosis was 11 months (range: 6–21) for the whole ALS cohort, 10 months (range: 6–15) in bulbar-onset (n = 65) and 12 months (range: 7–23) in spinal-onset (n = 195) patients (p = 0.3). 31.1% of patients received other diagnoses before ALS and this led to a significant delay of the correct diagnosis in this group (other diagnoses before ALS, n = 81: median delay, 15 months [9.75–24.25] vs ALS, n = 179, median delay, 9 months [6–15.25], p < 0.001).

Conclusions

The diagnostic delay in ALS is about one year, besides the growing number of tertiary centres and the spread of information about the disease through media and internet. Cognitive errors based on an incorrect use of heuristics might represent an important contributing factor. Furthermore, the length of the differential diagnosis from other disorders and delays in referral to the neurologist seems to be positively associated with the delay in diagnosis.     

Evaluation of ability for basic movement scale for children type T (ABMS-CT) for disabled children

Background

The objective of this pilot study was to test the validity and reliability of a new scale, the Ability for Basic Movement Scale for Children Type T (ABMS-CT).

Methods

Forty-nine pediatric patients with disabilities (aged 1.00–15.17 years; 29 males and 20 females) participated in this prospective study. To prove the validity and reliability of the ABMS-CT, subjects were administered the ABMS-CT by two physicians. In addition to the ABMS-CT score, data on age, diagnosis, and results of the Functional Independence Measure for Children (WeeFIM) were recorded.

Results

Spearman’s rank correlation coefficient analysis showed that the ability to perform basic movements according to the individual scores for each item on the ABMS-CT and the total scores of the ABMS-CT correlated significantly with the total scores of the motor and cognitive WeeFIM, respectively (r = 0.753–0.892, p = 0.0001). The five items on the ABMS-CT had appropriate internal consistency (Cronbach’s α = 0.966). Inter-rater reliability analysis indicated that the “oral and facial area”, “hands and fingers”, “one leg”, “both legs”, and “stairs” items on the ABMS-CT had almost perfect reliability (κ = 0.854–0.925).

Conclusion

This study provides evidence for the validity and reliability of the ABMS-CT with regard to assessment of the functional ability for complex movements in disabled pediatric patients even if they can walk independently.     

Does photoparoxysmal response in children represent provoked seizure? Evidence from simultaneous motor task during EEG

Objectives

Acute cognitive changes during epileptiform discharges have been studied using computer assisted cognitive tasks. We aimed to demonstrate acute behavioral change (using a simple motor response task MRT) during photoparoxysmal response (PPR) in children below 18 years.

Methods

Children performed a simple repetitive motor task during intermittent photic stimulation (IPS). All episodes of PPR not associated with obvious clinical change (as observed by the technologist or reported by the patient) were analyzed for this study. The average time interval between two successive motor responses across a PPR (test time) was compared to the average time interval between two successive motor responses during IPS not associated with PPR (control time) using Wilcoxon signed ranks test.

Results

21 children who had PPR successfully completed the MRT. The difference between the mean durations was 0.894 s (p = 0.002). More than 50% increase compared to the control time was considered a delay in MRT during PPR. 10 children showed slowing of MRT during PPR.

Conclusion

By definition, acute behavioral change during generalized epileptiform discharges represent provoked seizures. Detecting subclinical seizures can have important safety implications in children (skiing, skating and driving) with PPR on EEG, but no clinical seizures. We recommend MRT during IPS.     

Malignant glioma grade 3 and 4: How relevant is timing of radiotherapy?

Aims and background

The aim of this study is to determine prognostic factors that influence further outcome in patients with glioma.

Methods

Between 01/2002 and 08/2008, 153 patients with malignant gliomas of WHO-grade 3 or 4 who were treated with external beam radiotherapy with or without chemotherapy.

Results

In univariate analysis, following factors were ascertained as statistically significant prognostic parameters: grade (p = 0.000), time between operation and radiotherapy >24 days (p = 0.044) for progression-free survival; grade (p = 0.000), age < 58 years (p = 0.001), extent of surgery (p = 0.011), time between operation and radiotherapy >24 days (p = 0.009), overall treatment time >68 days (p = 0.003), use of chemotherapy (p = 0.015) for overall survival. A longer time period between resection and start of radiotherapy showed to be associated with improved outcome. After multivariate analysis, only grade (p = 0.000) remained a statistically significant factor for progression-free and grade (p = 0.000) and use of chemotherapy (p = 0.031) for overall survival.

Conclusions

We were able to recognize grade and use of chemotherapy as statistically significant prognostic determinants, but not time intervals or overall treatment time.     

Outcome of Chlamydia pneumoniae associated acute ischemic stroke in elderly patients: a case-control study

Background

Limited data exists about the role of Chlamydia pneumoniae elderly patients with acute ischemic stroke.

Objective

To study the role of C. pneumoniae in elderly patients (age more than 65 years) with acute ischemic stroke and its impact on stroke out come.

Methods

We recruited 100 elderly patients with acute ischemic stroke and 100 age and sex matched controls over a period of 2 years. IgG and IgA anti C. pneumoniae antibodies were measured by microimmunofluorescence technique in patients and controls. Good outcome was defined as a Modified Rankin score (mRS) of ≤2.

Results

We found C. pneumoniae antibodies in 35% stroke patients and in 18% control subjects (p = 0.01). Good out come at 90 days follow up was found in 20/35(57.1%) seropositive stroke patients compared to 37/65(56.9%) seronegative stroke patients (p = 0.9).

Conclusions

C. pneumoniae antibody positivity was independently associated with ischemic stroke in elderly patients and its presence does not alter the stroke outcome.     

Postural function in idiopathic normal pressure hydrocephalus before and after shunt surgery: A controlled study using computerized dynamic posturography (EquiTest)

Introduction

Postural dysfunction is one of the major features of idiopathic normal pressure hydrocephalus (iNPH). With computerized dynamic posturography (CDP) balance can be assessed objectively. The primary aim of this study was to describe the postural function in iNPH patients pre- and post-operatively in comparison with healthy individuals (HI) using CDP.

Subjects and methods

Thirty-five patients (16 M, 19 F) with a mean age of 73 (range 49–81) with iNPH, and sixteen HI (7 M, 9 F) aged 73 (62–89) were included. iNPH patients were operated on with a ventriculo-peritoneal shunt. Patients and HI were tested regarding motor function, balance and cognition. CDP, EquiTest (NeuroCom International, Clackamas, OR), was performed before and three months after shunt surgery and twice in HI, with a three-month interval.

Results

Pre-operatively, the 35 patients had poorer balance measured with the Sensory Organizing Test (SOT) score in every condition (p = 0.01 in SOT 1 and p < 0.001 in SOT 2–6) compared to the HI. The greatest difference was in test conditions measuring mainly vestibular function, where loss of balance (LOB) was frequent. Twenty patients were evaluated three months after shunt surgery and 18/20 (90%) of them were considered shunt responders, with a mean improvement of motor score of 26% (range 5–67%). There was an improvement post-operatively in the weighted composite SOT score (p < 0.05) but no significant change in any of the SOT conditions. LOB was not significantly reduced in any of the test conditions.

Conclusion

CDP showed that the patients had a poorer balance than the HI. The greatest difference was in SOT 5–6, indicating that the postural disturbance is of primarily central vestibular origin. There was a slight improvement of balance post-operatively.     

Quality of life in patients with focal dystonia

Objectives

The aims of this study were to identify the clinical and demographic factors influencing health-related quality of life (HR-QoL) and to compare HR-QoL measures between various types of focal dystonia (cervical dystonia, blepharospasm, and writer’s cramp).

Methods

We examined 157 consecutive patients with adult-onset primary focal dystonia, and HR-QoL was assessed by using the SF-36 questionnaire. Univariate and multivariate regression analyses were performed.

Results

Patients with writer’s cramp scored better in all SF-36 domains, except role functioning physical (RP), while these differences were statistically significant for physical functioning (PF) (p = 0.020), bodily pain (BP) (p = 0.001), and general health (GH) (p = 0.004). Patients with writer’s cramp and blepharospasm scored significantly better for BP (p = 0.001) than patients with cervical dystonia. We found that each of the eight dimensions of SF-36 proved to be significantly correlated to the Hamilton depression rating scale score in patients with torticollis and blepharospsm, while vitality (VT), social functioning (SF), and mental health (MH) scales showed statistically significant correlations in patients with hand dystonia. Similar relationships were observed between anxiety and SF-36 domains.

Conclusion

Depression and anxiety are the most important predictors of poorer HR-QoL in patients with all three types of focal dystonia.     

Representation of cricothyroid muscles at the primary motor cortex (M1) in healthy subjects, mapped by navigated transcranial magnetic stimulation (nTMS)

Objectives

To establish a methodology for mapping of primary motor cortex (M1) for cricothyroid (CTHY) muscles in a group of healthy subjects using three-dimensional (3D) magnetic resonance imaging (MRI) navigated transcranial magnetic stimulation (nTMS).

Methods

Two independent measurements were performed. Twelve right-handed healthy subjects were included in the study. In the first measurement, mapping of the abductor pollicis brevis (APB) muscle was followed by mapping of the M1 for CTHY. This was performed in 11 subjects. Second, to avoid bias concerning using a hand knob as a landmark, mapping of M1 for CTHY muscle was followed by mapping of M1 for APB. This was performed in three healthy subjects.The nTMS was used, with selective recordings of motor evoked potentials (MEPs) from APB muscle and corticobulbar motor evoked potentials (CoMEPs) from the CTHY muscle. For recording the responses from the CTHY muscle two hook wire electrodes (the size of 76 μm of diametre passing through 27 gauge needle) were inserted in the muscle. For the recording of MEPs from APB muscle, surface electrodes were used.

Results

First measurement: Stimulation over the left M1 for APB muscles elicits MEPs in the contralateral APB muscle with a mean latency of 22.8 ± 1.69 ms. Stimulation over the left M1 for the CTHY muscle elicits CoMEPs in the contralateral CTHY muscle with a mean latency of 11.89 ± 1.26 ms. The distance between the cortical representation for APB and CTHY was 25.19 ± 6.52 mm, with CTHY muscle representation lateral to the APB muscle.Second measurement: The results of second measurement of the distance between M1 for CTHY and M1 for APB and their cortical localisation were comparable to the results of the first measurement.

Conclusion

This is the first study with the aim to determine the exact cortical localisation of CTHY muscle with nTMS. Mapping of M1 for CTHY and APB muscles by nTMS was successfully performed in all healthy subjects. The exact location of the stimulating points over M1 muscles eliciting responses in CTHY and APB muscles was determined and superimposed over 3D MRI images. The data show that M1 for CTHY muscle is about 25 mm more lateral with regard to M1 for the APB muscle.

Significance

Mapping of M1 for CTHY muscle might represent an important neurophysiologic marker for facilitating preoperative mapping of motor speech-related cortical areas due to the proximity of motor cortical representation for laryngeal muscles and opercular part of the Broca area.     

Mismatch negativity and low frequency oscillations in schizophrenia families

Objective

Theta-alpha range oscillations have been associated with MMN in healthy controls. Our previous studies showed that theta-alpha activities are highly heritable in schizophrenia patients’ families. We aimed to test the hypothesis that theta-alpha activities may contribute to MMN in schizophrenia patients and their family members.

Methods

We compared MMN and single trial oscillations during MMN in 95 patients, 75 first-degree relatives, 87 controls, and 34 community subjects with schizophrenia spectrum personality (SSP) traits.

Results

We found that (1) MMN was reduced in patients (p < 0.001) and SSP subjects (p = 0.047) but not in relatives (p = 0.42); (2) there were augmented 1–20 Hz oscillations in patients (p = 0.02 to <0.001) during standard and deviant stimuli; (3) theta-alpha (5–12 Hz) oscillations had the strongest correlation to MMN in controls and relatives (ΔR² = 21.4–23.9%, all p < 0.001), while delta (<5 Hz) showed the strongest correlation to MMN in schizophrenia and SSP trait subjects; and, (4) MMN (h² = 0.56, p = 0.002) and theta-alpha (h² = 0.55, p = 0.004) were heritable traits.

Conclusions

Low frequency oscillations have a robust relationship with MMN and the relationship appears altered by schizophrenia; and schizophrenia patients showed augmented low frequency activities during the MMN paradigm.

Significance

The results encourage investigation of low frequency oscillations to elucidate the neurophysiological pathology underlying MMN abnormalities in schizophrenia.     

Prediction of infarct growth and neurologic deterioration in patients with positive perfusion-diffusion mismatch

Background

To assess the value of baseline clinical severity and perfusion–diffusion mismatch as predictors for further infarct growth and clinical outcome.

Methods

Patients with acute ischemic stroke and initial perfusion–diffusion mismatch within 72 h were enrolled. Baseline perfusion defects on time-to-peak (TTP) and cerebral blood volume (CBV) maps were measured. Infarct volume and stroke severity were assessed by diffusion-weighted image (DWI) and NIHSS, and were repeatedly assessed 7 days later. The predictive value of baseline NIHSS and perfusion defects on further infarct growth and neurologic deterioration was determined.

Results

Fifty-two patients (mean age 68.3 ± 12.8 years, 42% women) were enrolled. CBV defects were significantly associated with infarct growth (CBV, p = 0.02). Initial stroke severity, but not TTP and CBV mismatch (p = 0.65 and 0.76, respectively), significantly inversely correlated with neurologic deterioration (p = 0.001).

Conclusions

In patients with mismatch, those with severe symptoms initially are more likely to have infarct growth, while those with minor symptoms tend to suffer from larger extent of neurologic deterioration within 1 week. CBV is associated with further infarct growth but not clinical deterioration.     

Platelet poor plasma serotonin level in delinquent adolescents diagnosed with conduct disorder

Objective

Accumulating data indicate the involvement of the serotonergic system in adolescent aggression. The aim of this study was to examine the platelet-poor plasma (PPP) serotonin (5-HT) levels among delinquent adolescent boys with conduct disorder (CD) in comparison with normal controls.

Method

PPP 5-HT levels were measured in 16 male delinquent CD adolescents from a correctional facility and in 14 normal male adolescent controls. Severity of aggressive behavior was assessed by the Child Behavior Checklist (CBCL) and the Overt Aggression Scale (OAS).

Results

Delinquent CD adolescents had higher PPP 5-HT levels (about 3-fold) than the normal controls (27.68 ± 32.29 vs. 7.76 ± 4.23 ng/ml, respectively, p = 0.027). In the delinquent CD adolescents a significant correlation was found between the PPP 5-HT levels and the CBCL and OAS aggressive scores (r = 0.68, p = 0.0034 and r = 0.59, p = 0.016, respectively).

Conclusions

Juvenile delinquency is associated with high PPP 5-HT levels. Modulation of 5-HT neurotransmission may have a role in the symptomatology and treatment of severe adolescent CD.     

Postoperative changes in the superficial temporal artery and the external carotid artery duplex sonography after extra-intracranial bypass surgery in European Moyamoya disease

Introduction

Despite Duplex ultrasonography being a noninvasive, easily repeatable, readily available and economical tool, this examination and its normal ranges are rarely described in Moyamoya disease (MMD).

Methods

Duplex ultrasonography examinations of the superficial temporal artery (STA) and external carotid artery (ECA) were performed preoperatively, postoperatively (within 30 days) and as follow-up exams (6 months postoperatively) after 32 cerebral revascularization procedures in 20 European patients with MMD.

Results

A significant higher mean diastolic flow of STA compared to preoperative values was found in postoperative (p < .000) and follow-up exams (p < .001) in Duplex ultrasonography. Postoperative and follow-up Duplex sonography of STA also showed a significantly higher mean systolic flow compared to preoperative values (p < .05 and p < .05). Also ECA showed significantly changes after bypass surgery (p < .05).

Conclusion

Duplex ultrasonography of STA is a reliable and non-invasive tool to investigate hemodynamic changes after bypass surgery and to detect bypass patency in European patients with MMD.     

Manganese superoxide dismutase gene Ala-9Val polymorphism might be related to the severity of abnormal involuntary movements in Korean schizophrenic patients

Objective

This study examined whether the manganese superoxide dismutase (MnSOD) gene Ala–9Val single-nucleotide polymorphism (SNP) is associated with neuroleptic-induced tardive dyskinesia (TD) and the severity of the abnormal involuntary movements in Korean schizophrenic patients.

Method

We investigated whether the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients with (n = 83) and without (n = 126) TD who were matched for exposure to antipsychotics and other relevant variables.

Results

Logistic regression analysis revealed that being older (p = 0.026) was a risk factor for TD, but that there was no significant association between MnSOD gene and TD. Abnormal involuntary movements were more severe in carriers of the Ala allele than in noncarriers (p = 0.044).

Conclusion

These findings do not support that the MnSOD gene Ala–9Val SNP is associated with TD in Korean schizophrenic patients. However, this polymorphism might be related to the severity of abnormal involuntary movements in this population.     

Effect of concentration and mode of intrathecal baclofen administration on soleus H-reflex in patients with muscle hypertonia

Objectives

Assess spinal reflex excitability after increasing intrathecal baclofen (ITB) flow by manipulation of drug concentration and mode of administration.

Methods

The effect of concentration was assessed by comparing changes in H-reflex (H/M ratio) 1–6 h after a 50 μg ITB bolus at 50 μg/ml concentration administered manually via lumbar puncture (LP, duration 1–2 min, n = 27) to a 50 μg bolus at 500 μg/ml concentration programmed through the pump and delivered via intrathecal catheter (IC, duration 10 min) above simple continuous dose (25–100 μg/day, n = 16). The effect of mode of administration was assessed by comparing peak changes in H/M ratio after 50 μg IC bolus above simple continuous dose (complex continuous mode, n = 27) to simple continuous mode only (n = 22) at equivalent daily doses (75–150 μg/day).

Results

H/M decrease was faster and overall greater after LP than IC bolus (mean 1-h 77% vs. 63%, p = 0.012; 1–6 h 91% vs. 82%, p < 0.001, respectively). H/M ratio also decreased significantly more with complex (91%) than simple continuous mode of administration (78%, p = 0.025).

Conclusions

Lower ITB concentration and complex continuous mode of administration lead to greater decrease in H/M ratio.

Significance

Decreased spinal reflex excitability after adjustment of drug and pump parameters to increase ITB flow may result in better clinical response.