Muscle elastography: a new imaging technique for multiple sclerosis spasticity measurement

Multiple sclerosis (MS) spasticity is currently evaluated on the basis of neurological examinations such as Ashworth Scale (AS) and 0–10 NRS. Severity of spasticity is difficult to quantify. We investigated the use of real time elastography (RTHE) ultrasounds for evaluating objectively the muscle fibers status in MS spasticity patients and their changes after a new antispasticity treatment. Two studies were performed. In study A, 110 MS patients underwent a neurological evaluation based on the AS and RTHE. The RTHE images were scored with the new 1-5 muscle fibers rigidity imaging scale, here called MEMSs (Muscle Elastography Multiple Sclerosis Score). The correlation between AS and MEMSs was found to be statistically significant. In study B, 55 MS patients treated with THC:CBD oromucosal spray for their resistant spasticity were followed prospectively. MS spasticity was evaluated by the 0–10 NRS scale at baseline and after 4 weeks of treatment. MEMSs’ figures were obtained at both timepoints. Responders to THC:CBD oromucosal spray (pre-defined as an improvement ≥20% in their 0–10 NRS spasticity score vs. baseline) were 65% of sample. These patients had a mean 0-10 NRS reduction of 1.87 and a MEMSs reduction of 1.97 (P values <0.0001). The remaining 35% of patients, classified as clinically non-responders, showed still a significant mean reduction in MEMSs (0.8, P = 0.002). Our overall results showed that RTHE, operativized throughout MEMSs, could be an objective gold standard to evaluate MS muscle spasticity as well as the effectiveness of antispasticity therapy.     

Delta-9-tetrahydrocannabinol shows antispastic and analgesic effects in a single case double-blind trial

Summary A double-blind study was performed comparing 5 mg delta-9-tetrahydrocannabinol (THC) p.o., 50 mg codeine p.o., and placebo in a patient with spasticity and pain due to spinal cord injury. The three conditions were applied 18 times each in a randomized and balanced order. Delta-9-THC and codeine both had an analgesic effect in comparison with placebo. Only delta-9-THC showed a significant beneficial effect on spasticity. In the dosage of THC used no altered consciousness occurred.     

Sativex® as add-on therapy vs. further optimized first-line ANTispastics (SAVANT) in resistant multiple sclerosis spasticity: a double-blind,placebo-controlled randomised clinical trial

Purpose/aim: To evaluate the efficacy of tetrahydrocannabinol (THC):cannabidiol (CBD) oromucosal spray (Sativex^®) as add-on therapy to optimised standard antispasticity treatment in patients with moderate to severe multiple sclerosis (MS) spasticity.

Methods: Sativex^® as add-on therapy vs. further optimised first-line ANTispastics (SAVANT) was a two-phase trial. In Phase A, eligible patients received add-on THC:CBD spray for 4 weeks to identify initial responders [≥20% improvement from baseline in spasticity 0–10 numerical rating scale (NRS) score]. Following washout, eligible initial responders were randomised to receive THC:CBD spray or placebo for 12 weeks (double-blinded, Phase B). Optimisation of underlying antispasticity medications was permitted in both groups across all study periods.

Results: Of 191 patients who entered Phase A, 106 were randomised in Phase B to receive add-on THC:CBD spray (n?=?53) or placebo (n?=?53). The proportion of clinically relevant responders after 12 weeks (≥30% NRS improvement; primary efficacy endpoint) was significantly greater with THC:CBD spray than placebo (77.4 vs. 32.1%; p?<?0.0001). Compared with placebo, THC:CBD spray also significantly improved key secondary endpoints: changes in mean spasticity NRS (p?<?0.0001), mean pain NRS (p?=?0.0013), and mean modified Ashworth’s scale (p?=?0.0007) scores from Phase B baseline to week 12. Adverse events, when present, were mild/moderate and without new safety concerns.

Conclusions: Add-on THC:CBD oromucosal spray provided better and clinically relevant improvement of resistant MS spasticity compared with adjusting first-line antispasticity medication alone.     

Efficacy, safety and tolerability of an orally administered cannabis extract in the treatment of spasticity in patients with multiple sclerosis: a randomized, double-blind, placebo-controlled, crossover study

OBJECTIVE: Cannabis may alleviate some symptoms associated with multiple sclerosis (MS). This study investigated the effect of an orally administered standardized Cannabis sativa plant extract in MS patients with poorly controlled spasticity. METHODS: During their inpatient rehabilitation programme, 57 patients were enrolled in a prospective, randomized, double-blind, placebo-controlled crossover study of cannabis-extract capsules standardized to 2.5 mg tetrahydrocannabinol (THC) and 0.9 mg cannabidiol (CBD) each. Patients in group A started with a drug escalation phase from 15 to maximally 30 mg THC by 5 mg per day if well tolerated, being on active medication for 14 days before starting placebo. Patients in group B started with placebo for seven days, crossed to the active period (14 days) and closed with a three-day placebo period (active drug dose escalation and placebo sham escalation as in group A). Measures used included daily self-report of spasm frequency and symptoms, Ashworth Scale, Rivermead Mobility Index, 10-m timed walk, nine-hole peg test, paced auditory serial addition test (PASAT), and the digit span test. RESULTS: In the 50 patients included into the intention-to-treat analysis set, there were no statistically significant differences associated with active treatment compared to placebo, but trends in favour of active treatment were seen for spasm frequency, mobility and getting to sleep. In the 37 patients (per-protocol set) who received at least 90% of their prescribed dose, improvements in spasm frequency (P = 0.013) and mobility after excluding a patient who fell and stopped walking were seen (P = 0.01). Minor adverse events were slightly more frequent and severe during active treatment, and toxicity symptoms, which were generally mild, were more pronounced in the active phase. CONCLUSION: A standardized Cannabis sativa plant extract might lower spasm frequency and increase mobility with tolerable side effects in MS patients with persistent spasticity not responding to other drugs.     

THC/CBD oromucosal spray in patients with multiple sclerosis overactive bladder: a pilot prospective study

Lower urinary tract dysfunctions (LUTDs) are commonly reported in multiple sclerosis (MS) patients and are mainly related to neurogenic overactive bladder (OAB). The aim of this observational study was to assess the effect of a tetrahydrocannabinol-cannabidiol (THC/CBD) oromucosal spray on resistant OAB by means of clinical and instrumental tools. Twenty-one MS patients were screened, and 15 cases have been evaluated. They underwent a specific clinical assessment (overactive bladder symptom score, OABSS) and a urodynamic assessment evaluating the maximal cystometric capacity (CCmax), bladder compliance (Qmax), maximum detrusor pressure (Pdet max), detrusor pressure at the first desire (Pdet first), bladder volume at the first desire (BVFD), leakage volume (LV), and post-void residual volume (PVR), before and after 4 weeks of THC/CBD administration. A complete neurological evaluation, including the assessment of their spasticity using the Modified Ashworth Scale (MAS) and the spasticity 0–10 numerical rating scale (NRS), was performed at the same times. Mobility was evaluated through the 25-ft walking-time test (T25-WT). The THC/CBD treatment successfully reduced the OAB symptoms (p = 0.001). Regarding the urodynamic findings after the end of treatment, PVR was significantly reduced (p = 0.016). Regarding the urodynamic findings after the end of treatment, PVR was significantly reduced (p = 0.016), while BVFD and CCmax were increased although the difference was not statistically significant. THC/CBD oromucosal spray has shown to be effective in improving overactive bladder symptoms in MS patients demonstrating a favorable impact on detrusor overactivity.     

Randomized controlled trial of cannabis-based medicine in spasticity caused by multiple sclerosis

Symptoms relating to spasticity are common in multiple sclerosis (MS) and can be difficult to treat. We have investigated the efficacy, safety and tolerability of a standardized oromucosal whole plant cannabis-based medicine (CBM) containing Δ-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), upon spasticity in MS. A total of 189 subjects with definite MS and spasticity were randomized to receive daily doses of active preparation ( n  = 124) or placebo ( n  = 65) in a double blind study over 6 weeks. The primary endpoint was the change in a daily subject-recorded Numerical Rating Scale of spasticity. Secondary endpoints included a measure of spasticity (Ashworth Score) and a subjective measure of spasm. The primary efficacy analysis on the intention to treat (ITT) population ( n  = 184) showed the active preparation to be significantly superior ( P  = 0.048). Secondary efficacy measures were all in favour of active preparation but did not achieve statistical significance. The responder analysis favoured active preparation, 40% of subjects achieved >30% benefit ( P  = 0.014). Eight withdrawals were attributed to adverse events (AEs); six were on active preparation and two on placebo. We conclude that this CBM may represent a useful new agent for treatment of the symptomatic relief of spasticity in MS.     

Sativex long-term use: an open-label trial in patients with spasticity due to multiple sclerosis

Sativex is an endocannabinoid system modulator principally containing Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). During a 6-week randomised controlled trial, Sativex had a clinically relevant effect on spasticity associated with multiple sclerosis (MS). Patients self-titrated oromucosal Sativex to symptom relief or maximum tolerated dose (maximum of 130 mg THC and 120 mg CBD daily). The primary objective was to evaluate the safety and tolerability of long-term treatment by recording the incidence and severity of adverse events (AEs). Secondary outcomes were to determine evidence of developing tolerance and to assess the long-term dosing profile of Sativex. A validated 11-point Numerical Rating Scale of spasticity severity was used to assess efficacy. A total of 146 patients elected to enter this open-label follow-up safety trial. Mean treatment exposure was 334 days (standard deviation, SD = 209 days), and patients administered on average 7.3 (SD = 4.42) actuations per day. Fifty-two (36 %) patients withdrew from the study in the first year, 14 % due to AEs and 9 % due to lack of efficacy. Most AEs were mild/moderate in severity. Common (>10 %) treatment-related AEs were dizziness (24.7 %) and fatigue (12.3 %). Serious AEs occurred in five patients (3.4 %), with two psychiatric events reported by one patient. No psychoses, psychiatric AE trends, or withdrawal symptoms occurred following abrupt cessation of treatment. Baseline symptoms including spasticity did not deteriorate but were maintained to study completion in those patients who did not withdraw. No new safety concerns were identified with chronic Sativex treatment, and serious AEs were uncommon. There was no evidence of tolerance developing, and patients who remained in the study reported continued benefit.     

Cannabinoids for Treatment of MS Symptoms: State of the Evidence

Purpose of Review

Cannabis and cannabinoids have been used medically and recreationally for thousands of years and recently there has been a growing body of research in this area. With increased access now that medical marijuana is available in many jurisdictions, patients and providers want to know more about the evidence for benefits and risks of cannabinoid use. This paper provides an overview of the available cannabinoid-based formulations, a summary of the highest quality evidence for the use of cannabinoids for treating spasticity and pain associated with multiple sclerosis (MS), and a discussion of possible dosing regimens based on information from these studies.

Recent Findings

Two recent high-quality systematic reviews concluded that the only strong evidence for medical marijuana in neurological disorders was for reducing the symptoms of patient-reported spasticity and central pain in MS and that the only complementary and alternative medicine (CAM) intervention in MS with strong supportive evidence was cannabinoids. Based on this review, they concluded that nabiximols (Sativex oral spray), oral cannabis extract (OCE), and synthetic tetrahydrocannabinol (THC) are probably effective at reducing patient-reported symptoms of spasticity in people with MS, but OCE and synthetic THC were not found to be effective for reducing physician-administered measures of spasticity. In addition, nabiximols, OCE, and synthetic THC are probably effective at reducing MS-related pain. Cannabinoids were generally well-tolerated. However, cannabis use has been associated with an increased risk of psychosis and schizophrenia in at-risk individuals, there is growing evidence that cannabis can increase the risk for cardiovascular diseases, including myocardial infarction (MI), hypertension, heart failure, and stroke, and a recently recognized adverse effect of cannabis is cannabinoid hyperemesis syndrome.

Summary

The medical use of cannabinoids remains controversial. While cannabinoids have been studied for a variety of neurologic disorders, there is strongest evidence to indicate benefits in treatment of spasticity and neuropathic pain in multiple sclerosis. Although the best dose for an individual remains uncertain, most participants in the studies discussed in this paper used between 20 and 40 mg of THC a day in divided doses. Adverse events in studies were generally more common in the groups using cannabinoid products but serious adverse events were rare and cannabis products were generally well-tolerated. Cannabis use does appear to be associated with increased risk of certain adverse events, including psychosis, cardiovascular diseases, and cannabinoid hyperemesis syndrome.

     

Combination of cannabinoids,delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), mitigates experimental autoimmune encephalomyelitis (EAE) by altering the gut microbiome

Currently, a combination of marijuana cannabinoids including delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) is used as a drug to treat muscle spasticity in patients with Multiple Sclerosis (MS). Because these cannabinoids can also suppress inflammation, it is unclear whether such patients benefit from suppression of neuroinflammation and if so, what is the mechanism through which cannabinoids act. In the currently study, we used a murine model of MS, experimental autoimmune encephalomyelitis (EAE), to study the role of gut microbiota in the attenuation of clinical signs of paralysis and inflammation caused by cannabinoids. THC + CBD treatment attenuated EAE and caused significant decrease in inflammatory cytokines such as IL-17 and IFN-γ while promoting the induction of anti-inflammatory cytokines such as IL-10 and TGF-β. Use of 16S rRNA sequencing on bacterial DNA extracted from the gut revealed that EAE mice showed high abundance of mucin degrading bacterial species, such as Akkermansia muciniphila (A. muc), which was significantly reduced after THC + CBD treatment. Fecal Material Transfer (FMT) experiments confirmed that THC + CBD-mediated changes in the microbiome play a critical role in attenuating EAE. In silico computational metabolomics revealed that LPS biosynthesis, a key component in gram-negative bacteria such as A. muc, was found to be elevated in EAE mice which was confirmed by demonstrating higher levels of LPS in the brain, while treatment with THC + CBD reversed this trend. EAE mice treated with THC + CBD also had significantly higher levels of short chain fatty acids such as butyric, isovaleric, and valeric acids compared to naïve or disease controls. Collectively, our data suggest that cannabinoids may attenuate EAE and suppress neuroinflammation by preventing microbial dysbiosis seen during EAE and promoting healthy gut microbiota.     

Placebo Effects in a Multiple Sclerosis Spasticity Enriched Clinical Trial with the Oromucosal Cannabinoid Spray (THC/CBD): Dimension and Possible Causes

Regulatory authorities admit clinical studies with an initial enrichment phase to select patients that respond to treatment before randomization (Enriched Design Studies; EDSs). The trial period aims to prevent long‐term drug exposure risks in patients with limited chances of improvement while optimizing costs. In EDSs for symptom control therapies providing early improvements and without a wash‐out period, it is difficult to show further improvements and thus large therapeutic gains versus placebo. Moreover, in trials with cannabinoids, the therapeutic gains can be further biased in the postenrichment randomized phase because of carryover and other effects. The aims of the present review article are to examine the placebo effects in the enrichment and postenrichment phases of an EDS with Δ⁹‐tetrahydrocannabinol and cannabidiol (THC/CBD) oromucosal spray in patients with multiple sclerosis (MS) spasticity and to discuss the possible causes of maintained efficacy after randomization in the placebo‐allocated patients. The overall mean therapeutic gain of THC/CBD spray over placebo in resistant MS spasticity after 16 weeks can be estimated as a ~1.27‐point improvement on the spasticity 0–10 Numerical Rating Scale (NRS; ~?20.1% of the baseline NRS score). We conclude that careful interpretation of the results of EDSs is required, especially when cannabinoid‐based medications are being investigated.     

A double-blind, randomized, placebo-controlled, parallel-group study of THC/CBD oromucosal spray in combination with the existing treatment regimen, in the relief of central neuropathic pain in patients with multiple sclerosis

Central neuropathic pain (CNP) occurs in many multiple sclerosis (MS) patients. The provision of adequate pain relief to these patients can very difficult. Here we report the first phase III placebo-controlled study of the efficacy of the endocannabinoid system modulator delta-9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray (USAN name, nabiximols; Sativex, GW Pharmaceuticals, Salisbury, Wiltshire, UK), to alleviate CNP. Patients who had failed to gain adequate analgesia from existing medication were treated with THC/CBD spray or placebo as an add-on treatment, in a double-blind manner, for 14 weeks to investigate the efficacy of the medication in MS-induced neuropathic pain. This parallel-group phase of the study was then followed by an 18-week randomized-withdrawal study (14-week open-label treatment period plus a double-blind 4-week randomized-withdrawal phase) to investigate time to treatment failure and show maintenance of efficacy. A total of 339 patients were randomized to phase A (167 received THC/CBD spray and 172 received placebo). Of those who completed phase A, 58 entered the randomized-withdrawal phase. The primary endpoint of responder analysis at the 30 % level at week 14 of phase A of the study was not met, with 50 % of patients on THC/CBD spray classed as responders at the 30 % level compared to 45 % of patients on placebo (p = 0.234). However, an interim analysis at week 10 showed a statistically significant treatment difference in favor of THC/CBD spray at this time point (p = 0.046). During the randomized-withdrawal phase, the primary endpoint of time to treatment failure was statistically significant in favor of THC/CBD spray, with 57 % of patients receiving placebo failing treatment versus 24 % of patients from the THC/CBD spray group (p = 0.04). The mean change from baseline in Pain Numerical Rating Scale (NRS) (p = 0.028) and sleep quality NRS (p = 0.015) scores, both secondary endpoints in phase B, were also statistically significant compared to placebo, with estimated treatment differences of ?0.79 and 0.99 points, respectively, in favor of THC/CBD spray treatment. The results of the current investigation were equivocal, with conflicting findings in the two phases of the study. While there were a large proportion of responders to THC/CBD spray treatment during the phase A double-blind period, the primary endpoint was not met due to a similarly large number of placebo responders. In contrast, there was a marked effect in phase B of the study, with an increased time to treatment failure in the THC/CBD spray group compared to placebo. These findings suggest that further studies are required to explore the full potential of THC/CBD spray in these patients.     

Symptomatic treatment of multiple sclerosis using cannabinoids: recent advances

Recent years have seen a dramatic increase in the number of clinical trials investigating the potential efficacy of medicinal cannabinoids for the symptomatic treatment of chronic pain and spasticity in multiple sclerosis (MS). A number of different cannabinoids have been used, including: delta9-tetrahydrocannabinol (THC) itself; the synthetic delta9-THC, dronabinol; a 1:1 ratio of delta9-THC:cannabidiol (Sativex); and the synthetic delta9-THC metabolites CT-3 and nabilone. Other Cannabis extracts have also been tested. While 2-3 years ago there was little consensus in the literature, now the majority of studies are beginning to suggest that cannabinoids are useful in the treatment of MS in at least a subset of individuals. Their adverse side-effect profile has generally been mild compared with other drugs used for pain and spasticity; nonetheless, there is still concern about potential long-term side effects, particularly psychiatric side effects and effects on fetal development.     

Clonazepam, baclofen and placebo in the treatment of spasticity.

25 patients with multiple sclerosis (MS) and other spastic disorders, 33 MS patients and 10 control patients with MS were given clonazepam, baclofen or placebo over a period of 5 days to 20 weeks. Both clonazepam and baclofen were significantly more effective than placebo in the treatment of spasticity (p less than 0.005 or p less than 0.01). A clinical trial of clonazepam versus baclofen was carried out and this showed no significant difference between the two drugs. However, there was indication that clonazepam influenced with better improvement in patients with slight muscle hypertonia mainly of cerebral origin. Patients with more severe forms, mainly of spinal spasticity, benefited rather from baclofen treatment (Fisher's test, p = 0.003). There was suggestion that combination of the two drugs may be more effective in some patients than than clonazepam or baclofen alone.     

An open-label pilot study of cannabis-based extracts for bladder dysfunction in advanced multiple sclerosis

The majority of patients with multiple sclerosis (MS) develop troublesome lower urinary tract symptoms (LUTS). Anecdotal reports suggest that cannabis may alleviate LUTS, and cannabinoid receptors in the bladder and nervous system are potential pharmacological targets. In an open trial we evaluated the safety, tolerability, dose range, and efficacy of two whole-plant extracts of Cannabis sativa in patients with advanced MS and refractory LUTS. Patients took extracts containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD; 2.5 mg of each per spray) for eight weeks followed by THC-only (2.5 mg THC per spray) for a further eight weeks, and then into a long-term extension. Assessments included urinary frequency and volume charts, incontinence pad weights, cystometry and visual analogue scales for secondary troublesome symptoms. Twenty-one patients were recruited and data from 15 were evaluated. Urinary urgency, the number and volume of incontinence episodes, frequency and nocturia all decreased significantly following treatment (P <0.05, Wilcoxon's signed rank test). However, daily total voided, catheterized and urinary incontinence pad weights also decreased significantly on both extracts. Patient self-assessment of pain, spasticity and quality of sleep improved significantly (P <0.05, Wilcoxon's signed rank test) with pain improvement continuing up to median of 35 weeks. There were few troublesome side effects, suggesting that cannabis-based medicinal extracts are a safe and effective treatment for urinary and other problems in patients with advanced MS.     

A randomised, double blind, placebo controlled trial of botulinum toxin in the treatment of spastic foot in hemiparetic patients.

OBJECTIVE: To confirm the apparent effectiveness of botulinum toxin (BTX) in hemiparetic patients with ankle plantar flexors and foot invertor spasticity. METHODS: Twenty three hemiparetic patients with spasticity of the ankle plantar flexors and foot invertors were included in a randomised double blind, placebo controlled study with BTX. Patients were examined on days 0, 30, 90, and 120 and received one injection of BTX and one of placebo in a random order at day 0 and day 90. RESULTS: Patients reported a clear subjective improvement in foot spasticity after BTX (P = 0.0014) but not after placebo. Significant changes were noted in Ashworth scale values for ankle extensors (P < 0.0001) and invertors (P = 0.0002), and for active ankle dorsiflexion (P = 0.0001). Gait velocity was slightly but not significantly (P = 0.0731) improved after BTX injections. The severity of spasticity did not modify treatment efficacy, but BTX was less effective in patients with longer duration of spasticity (P = 0.0081). CONCLUSION: The efficacy of BTX injections in the treatment of spastic foot suggests that BTX may be particularly useful during the first year after a stroke.     

Adenosine A2A receptors are involved in physical dependence and place conditioning induced by THC

A2A adenosine and CB1 cannabinoid receptors are highly expressed in the central nervous system, where they modulate numerous physiological processes including adaptive responses to drugs of abuse. Both purinergic and cannabinoid systems interact with dopamine neurotransmission (through A2A and CB1 receptors, respectively). Changes in dopamine neurotransmission play an important role in addictive-related behaviours. In this study, we investigated the contribution of A2A adenosine receptors in several behavioural responses of Delta9-tetrahydrocannabinol (THC) related to its addictive properties, including tolerance, physical dependence and motivational effects. For this purpose, we first investigated acute THC responses in mice lacking A2A adenosine receptors. Antinociception, hypolocomotion and hypothermia induced by acute THC administration remained unaffected in mutant mice. Chronic THC treatment developed similar tolerance to these acute effects in wild-type and A2A-knockout mice. However, differences in the body weight pattern were found between genotypes during such chronic treatment. Interestingly, the somatic manifestations of SR141716A-precipitated THC withdrawal were significantly attenuated in mutant mice. The motivational responses of THC were also evaluated by using the place-conditioning paradigm. A significant reduction of THC-induced rewarding and aversive effects was found in mice lacking A2A adenosine receptors in comparison with wild-type littermates. Binding studies revealed that these behavioural changes were not associated with any modification in the distribution and/or functional activity of CB1 receptors in knockout mice. Therefore, this study shows, for the first time, a specific involvement of A2A receptors in the addictive-related properties of cannabinoids.     

Levetiracetam for phasic spasticity in multiple sclerosis

BACKGROUND: Spasticity is a common and debilitating symptom of multiple sclerosis (MS). Current treatments are effective, but may be difficult to tolerate for many patients. OBJECTIVE: To determine if levetiracetam, a second-generation antiepileptic drug, may be useful for the treatment of spasticity in MS. METHODS: A retrospective medical record review of patients attending the Multiple Sclerosis Program at the University of Texas, Southwestern Medical Center at Dallas was performed. A series of 12 patients who had been treated with levetiracetam for spasticity was identified. Most of the patients were female (10/11), and the mean age was 41.0 years. The main outcome measure was a change in Penn spasm score or modified Ashworth score. Both scores are measured on a scale of 0 to 4. RESULTS: The Penn Spasm score (a measure of phasic spasticity) was decreased for all patients following treatment with levetiracetam. The mean +/- SD Penn Spasm score was 2.7 +/- 0.65 at baseline and decreased to 0.9 +/- 0.29 at follow-up. There was no change in modified Ashworth scores (a measure of tonic spasticity). Five patients reported adverse events; 1 patient discontinued treatment owing to an adverse event (edema). Three patients incidentally reported improvements in neuropathic pain. CONCLUSIONS: Levetiracetam was effective for reducing phasic spasticity but not tonic spasticity in this 12-patient case series. The drug was well tolerated and therefore shows promise as a treatment for phasic spasticity. Large, well-controlled trials are needed to confirm these findings.     

The modulation of long-term potentiation by delta-9-tetrahydrocannabinol in the rat hippocampus, in vitro

The duration of long-term potentiation (LTP) of the CA1 evoked field potential in rat hippocampal slices was significantly modulated by pre-treatment of slices with delta-9-tetrahydrocannabinol (THC) added to the incubation media. The three THC doses tested: 10 picomolar (pM), 100 pM, and 1000 pM, resulted in a biphasic change in population spike amplitude, such that 10 pM resulted in an increase, while 100 and 1000 pM resulted in dose-related decreases as compared to the control treatment. Upon subsequent induction of LTP by tetanizing stimulation, the THC treatments resulted in significant changes in the duration but not magnitude of potentiation. The early component of potentiation, post-tetanic potentiation, or PTP, was not affected by the THC treatments. LTP was seen to decay in an exponential manner over the 121 mini post-tetanus monitoring period. For comparisons of LTP duration, therefore, the half-life (t1/2) of LTP was extrapolated from linear regression analysis. The t1/2 values were determined for each treatment group from the slopes of the linear regression analysis of the logarithmically transformed time course data. While the control group t1/2 was determined as 280 min, the t1/2 for the THC groups were: 350 min (10 pM); 91 min (100 pM); and 33 min (1000 pM) doses, respectively. In context with previous reports of the disruptive action of marihuana intoxication on learning and memory, these results suggest that one possible action of THC may be in modulating hippocampal electrophysiology and its role in short-term memory processes.     

Baclofen, a new antispastic drug. A controlled, multicenter trial in patients with multiple sclerosis.

A double-blind, five-week, multicenter trial was conducted to compare the effect of baclofen, a unique amino acid derivative, with that of placebo in the treatment of 106 patients with spasticity secondary to multiple sclerosis. A spasticity assessment method that included a neurological examination, physicians' clinical impressions of changes during treatment, and a patient's self-evaluation was used to determine efficacy. This method showed baclofen (70 to 80 mg daily maximum, titrated) is effective relative to placebo in relieving symptoms of spasticity, such as flexor spasms, pain and stiffness, resistance to passive joint movements, and tendon stretch reflexes. Patient self-evaluation results also showed a significant reduction in clonus. Side effects were generally mild and transient.