G. Della Marca

Seizure-induced brain lesions: a wide spectrum of variably reversible MRI abnormalities.

Introduction MRI abnormalities in the postictal period might represent the effect of the seizure activity, rather than its structural cause. Material and Methods Retrospective review of clinical and neuroimaging charts of 26 patients diagnosed with seizure-related MR-signal changes. All patients underwent brain-MRI (1.5-Tesla, standard pre- and post-contrast brain imaging, including DWI-ADC in 19/26) within 7 days from a seizure and at least one follow-up MRI, showing partial or complete reversibility of the MR-signal changes. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Seizure-induced brain-MRI abnormalities remained a diagnosis of exclusion. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined. Results MRI showed unilateral (13/26) and bilateral abnormalities, with high (24/26) and low (2/26) T2-signal, leptomeningeal contrast-enhancement (2/26), restricted diffusion (9/19). Location of abnormality was cortical/subcortical, basal ganglia, white matter, corpus callosum, cerebellum. Hippocampus was involved in 10/26 patients. Reversibility of MRI changes was complete in 15, and with residual gliosis or focal atrophy in 11 patients. Reversibility was noted between 15 and 150 days (average, 62 days). Partial simple and complex seizures were associated with hippocampal involvement (p=0.015), status epilepticus with incomplete reversibility of MRI abnormalities (p=0.041). Conclusions Seizure or epileptic status can induce transient, variably reversible MRI brain abnormalities. Partial seizures are frequently associated with hippocampal involvement and status epilepticus with incompletely reversible lesions. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention.

Functional involvement of cerebral cortex in adult sleepwalking.

The pathophysiology of adult sleepwalking is still poorly understood. However, it is widely accepted that sleepwalking is a disorder of arousal. Arousal circuits widely project to the cortex, including motor cortex. We hypothesized that functional abnormality of these circuits could lead to changes in cortical excitability in sleepwalkers, even during wakefulness. We used transcranial magnetic stimulation (TMS) to examine the excitability of the human motor cortex during wakefulness in a group of adult sleepwalkers. When compared with the healthy control group, short interval intracortical inhibition (SICI), cortical silent period (CSP) duration, and short latency afferent inhibition (SAI) were reduced in adult sleepwalkers during wakefulness. Mean CSP duration was shorter in patients than in controls (80.9 ± 41 ms vs. 139.4 ± 37 ms; p = 0.0040). Mean SICI was significantly reduced in patients than in controls (73.5 ± 38.4% vs. 36.7 ± 13.1%; p = 0.0061). Mean SAI was also significantly reduced in patients than in controls (65.8 ± 14.2% vs. 42.8 ± 16.9%; p = 0.0053). This neurophysiological study suggests that there are alterations in sleepwalkers consistent with an impaired efficiency of inhibitory circuits during wakefulness. This inhibitory impairment could represent the neurophysiological correlate of brain “abnormalities” of sleepwalkers like “immaturity” of some neural circuits, synapses, or receptors.

Functional involvement of cerebral cortex in human narcolepsy

The pathophysiology of human narcolepsy is still poorly understood. The hypoactivity of some neurotransmitter systems has been hypothesised on the basis of the canine model. To determine whether narcolepsy is associated with changes in excitability of the cerebral cortex, we assessed the excitability of the motor cortex with transcranial magnetic stimulation (TMS) in 13 patients with narcolepsy and in 12 control subjects. We used several TMS paradigms that can provide information on the excitability of the motor cortex. Resting and active motor thresholds were higher in narcoleptic patients than in controls and intracortical inhibition was more pronounced in narcoleptic patients. No changes in the other evaluated measures were detected. These results are consistent with an impaired balance between excitatory and inhibitory intracortical circuits in narcolepsy that leads to cortical hypoexcitability. We hypothesise that the deficiency of the excitatory hypocretin/orexin-neurotransmitter-system in narcolepsy is reflected in changes of cortical excitability since circuits originating in the lateral hypothalamus and in the basal forebrain project widely to the neocortex, including motor cortex. This abnormal excitability of cortical networks could be the physiological correlate of excessive daytime sleepiness and it could be the substrate for allowing dissociated states of wakefulness and sleep to emerge suddenly while patients are awake, which constitute the symptoms of narcolepsy.

Reduced sensorimotor inhibition in the ipsilesional motor cortex in a patient with chronic stroke of the paramedian thalamus

OBJECTIVE Unilateral or bilateral paramedian infarction in the region of the thalamus and upper midbrain may lead to hypersomnia. To determine whether unilateral infarction of the paramedian thalamus leads to changes in excitability of ipsilesional primary motor hand area (M1). METHODS We describe a patient with chronic stroke of the right dorsomedian and intralaminar thalamic nuclei, who suffered from mild persistent hypersomnia. We studied the excitability of the right and left M1 with transcranial magnetic stimulation (TMS) in the patient, and in 10 healthy controls. RESULTS In contrast to healthy controls, contralateral electrical stimulation of the median nerve failed to induce short-latency afferent inhibition (SAI) in the ipsilesional M1. Other measures of corticomotor excitability and somatosensory evoked potentials were normal. CONCLUSIONS The selective loss of ipsilateral SAI in a patient with paramedian thalamic stroke suggests that during wakefulness, the intact paramedian thalamus facilitates the excitability of intracortical inhibitory circuits, which process thalamocortical sensory inputs in the ipsilateral M1. This preliminary finding suggests that measurements of SAI may provide a means of probing the integrity of some neural pathways, which are involved in the control of wakefulness and arousal. SIGNIFICANCE In addition to the established role of the paramedian thalamus in arousal and memory, our observation suggests that thalamocortical projections from the paramedian thalamus contribute to the integration of sensory input at the cortical level during wakefulness.

Reduced cerebral cortex inhibition in dystonia: Direct evidence in humans

OBJECTIVE A loss of inhibition in central motor circuits resulting in abnormal motor control is the hypothesised cause of dystonia. So far, changes in inhibitory function of cerebral cortex in dystonia, have been revealed only indirectly by recording muscle responses evoked by transcranial magnetic stimulation (TMS) of the brain. The aim of present study was to evaluate more directly cerebral cortex changes in dystonia. We had the almost unique opportunity to record directly motor cortex output after brain stimulation, in a dystonic patient who had epidural electrodes implanted in the upper cervical cord. METHODS We evaluated descending activity evoked by single and paired pulse TMS together with the inhibitory effects produced by afferent stimuli on TMS evoked activity, and compared the results with those obtained in thirteen subjects with no central nervous system abnormality who also had cervical spinal electrodes. RESULTS The intrinsic inhibitory activity produced by paired TMS of the motor cortex, and the inhibitory effects produced by afferent inputs, were suppressed in the patient with dystonia. CONCLUSIONS These findings provide a direct evidence of the abnormality in motor cortex inhibitory systems in dystonia. SIGNIFICANCE The abnormality in cortical inhibitory system might have a role in the pathophysiology of dystonia.

Teaching NeuroImages: Transient epileptic amnesia

A 71-year-old man presented recurrent transient episodes of anterograde and retrograde amnesia, since age 60 years, with a frequency of 10 per month. The attacks, preceded by vague abdominal discomfort, lasted from a few minutes to 2–3 hours. History was unremarkable except for a head trauma; he took no drugs. MRI showed a left meningoencephalocele, likely posttraumatic, in the …

Recurrent Subarachnoid Bleeding and Superficial Siderosis in a Patient with Histopathologically Proven Cerebral Amyloid Angiopathy

A 68-year-old man with a history of hypertension presented with recurrent subarachnoid bleeding. Brain MRI showed superficial siderosis, and diagnostic cerebral angiograms did not show any intracranial vascular malformation or arterial aneurism. Post mortem neuropathological examination of the brain was consistent with a diagnosis of cerebral amyloid angiopathy. Clinicians should be aware that cerebral amyloid angiopathy should be considered in patients with unexplained recurrent subarachnoid bleeding, even in cases without familial clustering or transthyretin variant.

Relapsing demyelinating disease after chicken pox in a child

Post-infectious encephalomyelitis (PIE), an inflammatory demyelinating disorder, usually begins days to weeks after virus (usually measles, Epstein–Barr virus [EBV], cytomegalovirus [CMV], or varicella zoster virus [VZV]) or mycoplasma infection, and after vaccination with hepatitis B virus,1 Bordetella pertussis , and possibly influenza virus.2 The mechanism by which the infectious agent triggers demyelination is uncertain. Two days after varicella infection, a 3-year-old girl developed fever, confusion, lethargy, and status epilepticus. CSF was acellular with normal protein and glucose, without oligoclonal bands (OGBs) or amplifiable VZV DNA, and no VZV IgM or IgG antibody in serum or CSF. Brain CT revealed diffuse white matter edema. After IV treatment with ceftriaxone, acyclovir, clonazepam, and phenobarbital, seizures stopped and mental status was normal. Neurologic signs included increased DTRs, greater on the left, and ankle clonus bilaterally. Twenty days later, she became febrile. Neurologic signs consisted of ataxia with dysmetria bilaterally and intention tremor in the arms. Serum contained VZV IgM antibody, and VZV IgG was 6,800 international units (IU) per liter (normal < 50 IU/L). There was no amplifiable VZV DNA in blood. CSF was acellular, protein 31 mg%; …

Right Hemiparesis in Right Carotid Stenosis

A 72-year-old right-handed man with a history of hypertension and past smoking, taking low-dose aspirin therapy (100 mg once a day) for cardiovascular prevention, presented with sudden onset of right hemiparesis and confusion. The right hemiparesis improved during the following days, but the patient was still confused. He arrived at the emergency department 6 days after the onset of symptoms. On neurological examination, the patient showed mild disorientation both in time and in place; no other neurological signs could be elicited. Blood pressure was 160/90 mm Hg. Blood count, prothrombin time, activated thromboplastin time, ionogram, C-reactive protein, troponin Ic, and creatine kinase were normal. ECG revealed normal sinus rhythm (76 bpm). Extracranial …

RESTLESS LEGS SYNDROME WITH PERIODIC LIMB MOVEMENTS: A POSSIBLE CAUSE OF IDIOPATHIC HYPERCKEMIA

Idiopathic hyperCKemia is characterized by persistently increased serum creatine kinase (CK) encountered in healthy individuals with no evidence of neuromuscular diseases.1 They may complain of fatigue, cramps, and myalgia; these nonspecific symptoms overlap with the wide spectrum of limb discomfort reported by patients with restless legs syndrome (RLS). Nevertheless, hyperCKemia is not a laboratory finding in RLS. We describe 7 patients with idiopathic hyperCKemia in whom the diagnostic workup revealed the presence of RLS with periodic limb movements in sleep (PLMS). ### Methods. Seven patients (6 men, age 22–69 years; table) referred to a center for neuromuscular diseases for severe, persistent myalgia in the lower limbs, fatigue, and cramps were included. Laboratory tests revealed hyperCKemia, confirmed in at least 3 consecutive samples, at 30-day intervals, at rest. No patient reported assumption of statins or exposure to toxins. All showed lower limbs muscle hypertrophy, particularly of quadriceps and calves (figure e-1 on the Neurology ® Web site at www.neurology.org). Patients underwent an …