Intraoperative monitoring of somatosensory (SSEPs) and transcranial electric motor-evoked potentials (tce-MEPs) during surgical correction of neuromuscular scoliosis in patients with central or peripheral nervous system diseases.

PURPOSE: Combined intraoperative monitoring (IOM) of transcranial electric motor-evoked potentials (tce-MEPs) and somatosensory-evoked potentials (SSEPs) is safe and effective for spinal cord monitoring during scoliosis surgery. However, the literature data regarding the reliability of spinal cord monitoring in patients with neuromuscular scoliosis are conflicting and need to be confirmed. METHODS: We reviewed IOM records of 40 consecutive patients with neuromuscular scoliosis related to central nervous system (CNS) (29 pts) or peripheral nervous system (PNS) (11 patients) diseases, who underwent posterior fusion with instrumentation surgery for spinal deformity. Multimodalitary IOM with SSEPs and tce-MEPs was performed. RESULTS: Spinal cord monitoring using at least one modality was attempted in 38/40 (95 %) patients. No false-negative results were present in either group, but a relatively high incidence of false-positive cases (4/29, 13.8 %) was noted in the CNS group. Two patients in the CNS group and one patient in the PNS group presented transient postoperative motor deficits (true positive), related to surgical manoeuvres in two cases and to malposition in the other one. CONCLUSIONS: Multimodalitary IOM is safe and effective to detect impending spinal cord and peripheral nerves dysfunction in neuromuscular scoliosis surgery. However, the interpretation of neurophysiological data may be challenging in such patients, and the rate of false-positive results is high when pre-operatory motor deficits are severe.

Consistence and discrepancy of neuropathic pain screening tools DN4 and ID-Pain.

Pain is a subjective condition that cannot be objectively measured; for this reason, self patient-perspective is crucial. Recently, several screening tools to discriminate between nociceptive and neuropathic pain have been developed. We aimed at assessing the consistence and discrepancy of two widely used screening tools, The Douleur Neuropathique 4 (DN4) and the 6-item questionnaire (ID-Pain), by comparing their ability in discriminating neuropathic from nociceptive pain. DN4 and ID-Pain were administered to 392 Italian patients attending 16 outpatient services for peripheral nerve diseases. Based on medical history, clinical findings and diagnostic tools, patients were divided into two groups (neuropathic and nociceptive). Globally, ID-Pain identified neuropathic pain in 60 % of patients (38 % probable, 22 % likely). Interestingly also DN4 diagnosed neuropathic pain in 60 % of cases. A discrepancy was observed in 16 % of cases. DN4 and ID-Pain resulted to be highly interrelated in the identification of neuropathic pain. Sensitivity of DN4 was 82 % and specificity was 81 %, while ID-Pain (considering both probable and likely groups) showed sensitivity 78 % and specificity 74 %. Reliable screening tools for neuropathic pain are well related between them; hence, they are available for researchers and clinicians who may choose the most appropriate for their activity. Since the gold standard for the diagnosis and treatment of neuropathic pain cannot do without a neurological evaluation, perhaps DN4, that includes physician objective measures, may help reducing the percentage of dubious cases. Conversely, when needing a more agile tool (not needing a physician) ID-Pain may be adopted.

The prevention of neural complications in the surgical treatment of scoliosis: the role of the neurophysiological intraoperative monitoring.

Iatrogenic spinal cord injury is the most feared complication of scoliosis surgery. The importance of combined somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) monitoring during spine surgery is well known. The current authors retrospectively evaluated the results of neurophysiological intraoperative monitoring (IOM) in a large population of patients who underwent surgical treatment for spinal deformity. Intraoperative monitoring of SEPs and transcranial electrical stimulation MEPs (TES-MEP) was performed in 172 successive patients who underwent surgical treatment of idiopathic (128 pts), congenital (15 pts) or syndromic (29 pts) scoliosis. The first 106 patients (Group 1) underwent only SEP monitoring, while the other 66 patients (Group 2) underwent combined SEP and TES-MEP monitoring, when the technique was introduced in the current authors' institution. Halogenate anaesthesia (Sevoflurane, MAC 0.6-1.2) was performed in Group 1 cases, total intravenous anaesthesia (Propofol infusion, 6-10 mg/kg/h) in Group 2 patients. A neurophysiological "alert" was defined as a reduction in amplitude (unilateral or bilateral) of at least 50% for SEPs and of 65% for TES-MEPs compared with baseline. In Group 1, two patients (1.9%) developed postoperative neurologic deficits following surgical correction of spinal deformity, consisting of permanent paraparesis in one case and transient paraparesis secondary to spinal cord ischaemia in the other. Twelve patients presented intraoperative significant changes of neurophysiological parameters that improved following corrective actions by surgeons and anaesthesiologists, and did not show any postoperative neurologic deficits. In ten cases the alert was apparently unrelated to surgical manoeuvres or to pharmacological interventions and no postoperative neurologic deficits were noted. Considering the patients of Group 2, two patients (3.0%) presented transient postoperative neurologic deficits preceded by significant intraoperative changes in SEPs and TES-MEPs. In five cases a transient reduction in the amplitudes of SEPs (1 patient) and/or TES-MEPs (5 patients) was recorded intraoperatively with no postoperative neurologic deficits. In conclusion, in the current series of 172 patients the overall prevalence of postoperative neurologic deficit was 2.3% (4 patients). When combined SEP and TES-MEP monitoring was performed, the sensitivity and specificity of IOM for sensory-motor impairment was 100 and 98%, respectively. Combined SEP and TES-MEP monitoring must be regarded as the neurophysiological standard for intraoperative detection of emerging spinal cord injury during corrective spinal deformity surgery. Early detection affords the surgical team an opportunity to perform rapid intervention to prevent injury progression or possibly to reverse impending neurologic sequelae.

Denervation findings on EMG in amyotrophic lateral sclerosis and correlation with prognostic milestones: Data from a retrospective study.

OBJECTIVE: To verify whether the finding of denervation activity on EMG at the time of diagnosis has a prognostic value in amyotrophic lateral sclerosis (ALS). METHODS: We retrospectively studied all the patients discharged with a diagnosis of ALS between January 2009 and January 2017. 92 patients met the inclusion criteria. We mainly verified three prognostic targets:All EMG examinations were reviewed and a denervation score (DS) was calculated. The association of DS with clinical milestones was analysed, adjusting for disease duration, age , sex, and clinical phenotype. RESULTS: We found a significant association between bulbar DS and time to NIV/tracheostomy (HR: 3.34, 95% CI: 1.49 to 7.48, p = 0.002) and with survival (HR 3.633, 95% CI 1.681-7.848, p = 0.001), regardless of the clinical phenotype. Furthermore, we found a significant influence of a general DS on survival (HR: 2.62, 95% CI 1.335-5.160, p = 0.005). CONCLUSION: EMG assessment could be of value not just for ALS diagnosis but also for its intrinsic prognostic value. SIGNIFICANCE: EMG could provide additional information about the rate of progression of ALS as early as the diagnosis is made.

Brainstem neurodegeneration correlates with clinical dysfunction in SCA1 but not in SCA2. A quantitative volumetric, diffusion and proton spectroscopy MR study.

Magnetic resonance (MR) techniques enable in vivo measurement of the atrophy of the brainstem and cerebellum in spinocerebellar ataxia type 1 (SCA1) and 2 (SCA2) patients, which is accompanied by a decrease in the concentration of N-acetyl aspartate (NAA) or of the NAA/creatine ratio in the pons and cerebellum. Mean diffusivity (D) is emerging as an additional sensitive and quantitative MR parameter to investigate brain diseases. In order to explore differences between the MR features of SCA1 and SCA2 and correlate the MR and clinical findings in the two conditions, we examined 16 SCA1 patients, 12 SCA2 patients and 20 healthy control subjects. The MR protocol included T1-weighted 3D gradient echo sequences, single-voxel proton spectroscopy of the right cerebellar hemisphere (dentate and peridentate region) and of the pons with a PRESS sequence and an external reference quantitation method, and (in nine patients with SCA1 and nine patients with SCA2) diffusion-weighted echo-planar images with reconstruction of the D maps. The patients were evaluated with the Inherited Ataxia Clinical Rating Scale (IACRS). Compared with control subjects, the SCA1 and SCA2 patients showed a decrease (P < 0.01) in the volume of the brainstem and cerebellum and in the concentration of NAA in the pons and cerebellar hemisphere, whereas D of the brainstem and cerebellum was increased. No significant difference was observed between the SCA1 and SCA2 patient groups. No correlation between cerebellar volume and dentate and peridentate NAA concentration was found in SCA1 or SCA2 patients. The volume of the brainstem, D of the brainstem and cerebellum and the concentration of NAA in the pons were correlated (P < 0.05) with the IACRS score in SCA1 but not in SCA2. This discrepancy is in line with the clinical observation that the clinical deficit has a later onset and faster progression in SCA1 and an earlier onset and slower progression in SCA2, and suggests that neurodegeneration of the brainstem is a comparatively more rapid process in SCA1. In conclusion, our study indicates that SCA1 and SCA2 substantially exhibit the same MR features. The correlation in SCA1 between clinical severity and quantitative volumetric, diffusion MRI and proton MR spectroscopy findings in the brainstem indicates that these measurements might be employed for longitudinal studies and hopefully as surrogate markers in future pharmacological trials of this condition.

Transthyretin amyloidosis and superficial siderosis of the CNS.

OBJECTIVE: To describe a previously unreported clinical and radiologic presentation of hereditary transthyretin (TTR)-related amyloidosis. BACKGROUND: Unexplained cerebellar ataxia, pyramidal syndrome, and hearing loss are observed in some patients with TTR-related amyloidoses. METHODS: We performed clinical, radiologic, and pathologic examinations of three family members with TTR-related (Ala36Pro) amyloidosis. RESULTS: The patient was a 69-year-old woman with vitreal amyloid deposits, progressive sensorineural deafness, cerebellar ataxia, pyramidal syndrome, and recurrent transient neurologic symptoms. Cranial MRI showed symmetric thin rims of low signal intensity in T2- and T2*-weighted images in the cortex of the sylvian fissures, of the cerebellar hemispheres and vermis, and in the quadrigeminal plate consistent with superficial siderosis of the CNS. Her older daughter had vitreal amyloid deposits, acute Brown-Sequard syndrome at C4, acute sensorineural deafness, and recurrent transient neurologic symptoms. Cranial MRI at age 48 revealed a rim of low signal intensity in T2- and T2*-weighted images in the superior vermis folia and the right sylvian cortex. In addition, two small hemosiderin deposits were seen in the left parietal cortex. Lumbar puncture yielded colorless CSF with increased ferritin content and was followed by fourth ventricle hemorrhage. Cranial MRI 11 months later showed progression of brain hemosiderin deposits. The younger daughter had vitreal deposits, sensorimotor polyneuropathy, and acute sensorineural hearing but no evidence of siderosis on cranial MRI. She died at age 43 years of posterior fossa subarachnoid hemorrhage, and the neuropathologic examination showed amyloid deposition in the leptomeningeal spaces and vessels. CONCLUSION: Transthyretin-related amyloidosis may cause superficial siderosis of the CNS through subarachnoid bleeding related to meningovascular amyloid deposition.

Transcranial magnetic stimulation in epileptic patients: usefulness and safety.

We studied 58 patients with partial or generalized epilepsy who had transcranial magnetic stimulation (TMS) of the brain motor regions. Short-term monitoring disclosed that the stimulation did not provoke seizures or EEG changes in any patient. Long-term follow-up disclosed that the epileptic condition was not made worse by TMS. TMS, as currently used for monitoring conduction in central motor pathways, does not induce seizures in drug-treated epileptic patients.

Hypertension, hyperekplexia, and pyramidal paresis due to vascular compression of the medulla.

MRI showed impingement of the vertebral artery on the left lateral medulla in two patients with arterial hypertension, exaggerated startle reflexes (hyperekplexia), and progressive spastic paresis. One patient underwent microvascular decompression with normalization of arterial hypertension, disappearance of hyperekplexia, and improvement of spastic paresis. The combination of arterial hypertension, hyperekplexia, and progressive spastic paresis should arouse suspicion of neurovascular compression of the lateral medulla.

Androgen receptor gene (CAG)n repeat analysis in the differential diagnosis between Kennedy disease and other motoneuron disorders.

An increase in the number of (CAG)n repeats in the first coding exon of the androgen receptor (AR) gene has been strongly associated with Kennedy disease (KD) (spinal and bulbar muscular atrophy). This is an X-linked hereditary disorder characterized by motoneuron degeneration occurring in adults together with gynecomastia and hyperestrogenemia. We have performed AR gene molecular analysis in several members of a large family with KD as well as in 25 sporadic patients suffering from heterogeneous motoneuron disease (MND). An increase in the length of the (CAG)n repeats was detected, as expected, in all the affected males and in obligatory carrier females, some of which had minor signs of lower motoneuron involvement. There was only one possible exception, one young male with initial signs of the disease, who had an apparent normal length allele. An increased pathological allele was also found in 3 patients with MND. This indicates that the analysis of (CAG)n repeats of the AR gene plays a role in the differential diagnosis of this heterogeneous group of neurological diseases.

Epileptic negative myoclonus.

ENM is an etiologically heterogeneous disorder clinically evident as brief (less than 500 msec) lapses of tonic muscular contraction which seems to be related to lesions or dysfunction of different anatomofunctional levels of the CNS (Fig. 13). ENM can occur in heterogeneous epileptic disorders, ranging from benign syndromic conditions (such as BECTS) to focal static lesional epilepsy, as in neuronal migration disorders, and even to severe static or progressive myoclonic encephalopathies (PMEs). Neurophysiological studies in patients with ENM lead to the following conclusions: 1. A cortical origin of ENM is supported by EEG mapping and dipole analysis of spikes related to the ENM. In particular, our data suggest that the focal spike is a paroxysmal event involving, primarily or secondarily, the centroparietal and frontal "supplementary" motor areas. 2. A cortical inhibitory active mechanism for the genesis of ENM is supported by the occurrence of a decreased motor response to TMS, with preserved spinal excitability as demonstrated by the persistence of F waves. A "cortical motor outflow inhibition" related to spike-and-wave discharges was suggested by Gloor in his Lennox lecture (34). The cortical reflex negative myoclonus, described by Shibasaki et al. (16) in PME, is also consistent with a cortical active inhibitory mechanism. The spike associated with ENM raises new issues about the definition of "interictal" versus "ictal" EEG paroxysmal activity. A single spike on the EEG can be clinically silent (therefore, "interictal") or clinically evident as ENM (then viewed as "ictal"), depending on whether a given group of muscles is at rest or is showing tonic activity (see Fig. 4). These data, from a more general perspective, imply that the motor manifestation related to EEG paroxysmal events can depend not only on amplitude, topography, or intracortical distribution of seizure activity (35), but also on plasticity (36) and on the functional condition of the motor system (37). The variability of latency between the spike and the onset of the muscular inhibition (ranging from 15 to 50 msec, for the upper limbs), and the variability of duration of the ENM itself (from 50 to 400, or more, msec) indicate that ENM could be the result of inhibitory phenomena arising not only from a single cortical "inhibitory" area, but also from subcortical and pontine structures, as discussed by Mori et al. (this volume). The neurophysiological distinction between ENM and postmyoclonic periods of muscular suppression, mainly related to an EGG slow wave, as described by Lance and Adams (2) in the postanoxic action myoclonus is still a matter of discussion (38, 39). This is also the case for other movement disorders combining action myoclonus and epilepsy-as described in Ramsay Hunt syndrome (30), now better referred to as Unverricht-Lundborg syndrome (40) (Fig. 14). In these conditions, myoclonia and muscular silent periods are inconstantly associated with paroxysmal EEG discharges, suggesting a possible thalamocortical mechanism rather than a purely cortical one. In the most prolonged muscular inhibitions, both cortical and thalamocortical mechanisms might be implicated. Clearly, our knowledge of ENM is still very limited and gaining further insights into this complex phenomenon is a challenging problem.

Extreme somatosensory evoked potentials (ESEPs) elicited by tapping of hands or feet in children: a somatosensory cerebral evoked potentials study.

Six children with tactile-evoked spikes in the EEG, also defined as extreme somatosensory evoked potentials (ESEPs), underwent an SEPs study in order to define the characteristics of such evoked potentials. Short-latency SEPs showed normal mean latency and amplitude values. Mid- or long-latency SEPs of abnormally high amplitude were recorded after stimulation of one or more extremities. Such extreme responses which showed the same reactivity proper to normal long-latency SEPs could be considered to correspond to the evoked spikes in the EEG.

Muscle fiber splitting, capillary internalization, and target-like fiber formation in familial amyloidotic polyneuropathy.

A case of familial amyloidotic polyneuropathy (FAP) is reported in which peripheral nerve and skeletal muscle biopsies were obtained from the right leg to assess the severity of the relatively late-onset but rapid-evolving neuropathy. The present paper deals with some remarkable features found in the muscular biopsy, taken from peroneus brevis and extensor digitorum longus muscles. Several fibers contained amyloid masses characterized by Congo red positivity and birefringence on polarized light microscopy: histoenzymologic staining revealed that these fibers were always type 2B and appeared grossly hypertrophied. The presence of amyloid inside the muscle fibers was possibly dependent on the internalization of capillaries leading to direct deposition of amyloid fibrils into the sarcoplasm. Fiber vascularization occurred independently of fiber splitting, which appeared to be frequent in both muscles and was characterized by unusual segmental changes in the histochemical properties of the daughter fibers with respect to those of the parent fiber. Target/targetoid and degenerating areas were also observed in a large number of type 2 fibers, usually in close relationship with segmental splitting phenomena. These findings were interpreted as possible secondary myopathic changes accompanying chronic denervation-reinnervation episodes in the course of FAP.

Chronic cerebro-spinal venous insufficiency: report of transcranial magnetic stimulation follow-up study in a patient with multiple sclerosis.

The pyramidal pathway is frequently affected early on in multiple sclerosis (MS) and impaired motor performance is a major cause of disability. Pyramidal tract function can be assessed using transcranial magnetic stimulation (TMS). TMS supports the diagnosis of MS, detecting corticospinal tract involvement and monitoring its course with or without treatment. It has been never investigated whether any relationship exists between the TMS outcome measure and minimally invasive treatment of multiple severe extracranial stenosis, affecting the principal ce rebrospinal venous segments in MS patients. We report the clinical and transcranial magnetic stimulation follow-up of a patient during a relapse in relapsing-remitting MS. She underwent percutaneous balloon angioplasty of the associated chronic cerebrospinal venous insufficiency (CCSVI), due to membranous obstruction of the proximal azygous vein, with severe stenosis of the left internal jugular vein. Treatment of the associated CCSVI made a parallel improvement in both clinical and neurophysiological parameters, allowing us to avoid high dose steroid therapy. The relationship between the clinical and neurophysiological course on the one hand, and haemodynamic correction of the associated CCSVI on the other, calls for further exploration on a wider number of patients. The impact of CCSVI on the different neuro-physiological parameters has not been fully estimated, but the intriguing case here reported suggests that it may be greater than previously assumed. The demonstration of a modification of the cerebrovenous function with both clinical manifestation and via TMS suggests that the hampered cerebral venous return may contribute to the clinical course of MS.

Neuropathy in multiple myeloma treated with thalidomide: a prospective study.

BACKGROUND: Thalidomide is effective as a first-line therapy for the treatment of multiple myeloma (MM), but its use is limited by peripheral neurotoxicity. OBJECTIVE: To study the occurrence of both myeloma-related neuropathy and thalidomide-induced neuropathy in 31 patients with newly diagnosed MM. METHODS: Clinical and electrophysiologic examinations were performed in 31 patients with newly diagnosed MM before and after 4 months of therapy with thalidomide (200 mg/day, total dose: 21 g) aimed at debulking MM, before autologous transplantation. After transplantation, the patients took thalidomide, 200 mg/day for another 3 months (total dose over three months: 18 g) and then underwent a final clinical and electrophysiologic checkup. RESULTS: At baseline, four patients presented a mild sensorimotor peripheral neuropathy related to MM, which tended to worsen slightly during treatment with thalidomide. At the end of treatment, 83% of the patients had clinical and electrophysiologic evidence of a mild sensory rather than motor, axonal, length-dependent polyneuropathy, whereas 100% of the patients showed improvement to the basic pathology (>or=partial response). CONCLUSIONS: Peripheral neuropathy, sometimes subclinical, and mild in our patients, is a common, early side effect of thalidomide therapy. The high doses (21 g) used in all patients for a relatively short time (4 months) rule out any correlations between neuropathy, total dose, and duration of treatment.

Early onset aggressive hereditary amyloidosis: report of an Italian family with TTR Arg47 mutation.

Arg47 is a rare transthyretin-related (TTR) amyloidosis variant that is characterised by polyneuropathy and autonomic failure. We describe an Italian family with this mutation whose members (two women and their father) showed a rapid progression of the peripheral nervous system involvement and died within 5 years of clinical onset. Patients with Arg47 or other aggressive TTR amyloidoses should be considered high priority patients for orthotopic liver transplantation.

Amyloid deposits inside myocardial fibers in transthyretin-Met30 familial amyloidotic polyneuropathy. A histological and biochemical study.

A case of severe cardiac involvement is reported in a patient affected with familial amyloidotic polyneuropathy due to the Portuguese type I variant (Val-->Met30) of the transthyretin (prealbumin) molecule. Echocardiographic and hemodynamic studies suggested the presence of a progressive infiltrative cardiomyopathy that was later confirmed by endomyocardial biopsy. Amyloid deposits were found in both intra- and extra-myofiber location and thought to be related to primary involvement of the heart. Norepinephrine content of myocardial bioptic specimens was about threefold lower than normal, indicating that autonomic denervation may contribute to the maintenance and progression of cardiomyopathy. A sample obtained from the sural nerve showed a loss of myelinated fibers along with accumulation of amyloid masses in the endoneurial space. This histopathologic pattern correlated with a sharp decrease in the activity of the enzyme subserving electrochemical conduction through the axonal membrane, Na+, K(+)-ATPase.

Electromyographic findings in transthyretin (TTR)-related familial amyloid polyneuropathy (FAP).

Affected members and asymptomatic relatives of 9 Italian families with transthyretin (TTR)-related hereditary amyloidosis carrying different TTR mutations (Met30, Pro36, Ala47, Ala49, Gln89) were followed up with repeated EMG investigations. In 3 patients, spontaneous myoclonic discharges with synkinesia were found in the facial muscles. EMG signs of chronic denervation with features of proximal neural involvement were also found in proximal limb muscles. Neuropathy worsened step-wise with progressing clinical stage. Sympathetic skin responses progressively decreased, disappearing in the late stages of the disease. Symptomatic relatives carrying the TTR mutations had significantly reduced sensory conduction velocities and amplitudes of compound motor action potentials. Follow-up studies in 3 patients after liver transplant showed progression of sensory-motor neuropathy 1 year after the transplant, and a slight improvement 18 months later. Based on our electrophysiological findings and a review of the literature, we propose that TTR-related FAP type I be considered not only a peripheral neuropathy, but also a meningoradiculopathy due to deposition of amyloidogenic TTR in the leptomeninges.

Restless legs syndrome and nocturnal myoclonus: initial clinical manifestation of familial amyloid polyneuropathy.

Restless legs syndrome was the first isolated clinical manifestation in four siblings of a family with familial amyloid polyneuropathy. Clinical and electrophysiological evidence of peripheral neuropathy appeared after a variable time interval. Polysomnography showed abnormal sleep patterns and nocturnal myoclonus in all patients. The restless legs syndrome responded favourably to clonazepam.

Slowly progressive familial dementia with recurrent strokes and white matter hypodensities on CT scan.

We describe 2 normotensive sisters presenting slowly progressive dementia associated with acute or subacute focal neurological symptoms, unilateral or bilateral motor signs, and dysarthria. Their father, who died in the seventh decade, had a similar clinical picture. Computerized axial tomography (CT) scan of the head showed symmetrical hypodensities in the periventricular white matter and mild to moderate hydrocephalus. In these patients a diagnosis of Binswanger's disease was based on the clinical features supported by white matter changes on CT scan. Our study suggests that genetic factors may play a role in the etiology of Binswanger's disease.