The interpretation of mu suppression as an index of mirror neuron activity: past, present and future

Mu suppression studies have been widely used to infer the activity of the human mirror neuron system (MNS) in a number of processes, ranging from action understanding, language, empathy and the development of autism spectrum disorders (ASDs). Although mu suppression is enjoying a resurgence of interest, it has a long history. This review aimed to revisit mu’s past, and examine its recent use to investigate MNS involvement in language, social processes and ASDs. Mu suppression studies have largely failed to produce robust evidence for the role of the MNS in these domains. Several key potential shortcomings with the use and interpretation of mu suppression, documented in the older literature and highlighted by more recent reports, are explored here

PCA-induced respiratory depression simulating stroke following endoluminal repair of abdominal aortic aneurysm: a case report

<p>Abstract</p> <p>Aim</p> <p>To report a case of severe respiratory depression with PCA fentanyl use simulating stroke in a patient who underwent routine elective endoluminal graft repair for abdominal aortic aneurysm (AAA)</p> <p>Case presentation</p> <p>A 78-year-old obese lady underwent routine endoluminal graft repair for AAA that was progressively increasing in size. Following an uneventful operation postoperative analgesia was managed with a patient-controlled analgesia (PCA) device with fentanyl. On the morning following operation the patient was found to be unusually drowsy and unresponsive to stimuli. Her GCS level was 11 with plantars upgoing bilaterally. A provisional diagnosis of stroke was made. Urgent transfer to a high-dependency unit (HDU) was arranged and she was given ventilatory support with a BiPap device. CT was performed and found to be normal. Arterial blood gas (ABG) analysis showed respiratory acidosis with PaCO₂81 mmHg, PaO₂140 mmHg, pH 7.17 and base excess -2 mmol/l. A total dose of 600 mcg of fentanyl was self-administered in the 16 hours following emergence from general anaesthesia. Naloxone was given with good effect. There was an increase in the creatinine level from 90 μmol/L preoperatively to 167 μmol/L on the first postoperative day. The patient remained on BiPap for two days that resulted in marked improvement in gas exchange. Recovery was complete.</p

Ictal Cortical Blindness with Permanent Visual Loss

Cortical blindness is rarely an ictal manifestation. We report the case of a man who developed transient cortical blindness followed by permanent visual deficits during repeated partial seizures. Intermittent visual impairment began at age 14 years. After he had the first generalized seizure at age 28 years, neurologic, ophthalmologic, angiographic, and brain computed tomographic (CT) examinations were normal. Several EEGs showed almost continuous biposterior spike-waves. Over the next several years, frequent partial seizures were associated with transient visual loss and left body twitching or paresthesias. When he was 32, transient blindness occurred during several days of repeated occipital seizures. Permanent left homonymous hemianopia, right homonymous central scotoma, dyschromatopsia, and altered stereopsis followed these seizures. Brain CT demonstrated a new right occipital lesion. Partial seizures arising posteriorly may cause transient cortical blindness and result in permanent visual deficits.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65600/1/j.1528-1157.1989.tb05292.x.pd

Thyroid-stimulating hormone elevation misdiagnosed as subclinical hypothyroidism following non-convulsive status epilepticus: a case report

<p>Abstract</p> <p>Introduction</p> <p>Non-convulsive status epilepticus is a form of epileptic seizure that occurs without convulsions. Recent reviews suggest that the diagnosis of non-convulsive status epilepticus remains difficult. Here, we report the case of a patient with thyroid-stimulating hormone elevation misdiagnosed as subclinical hypothyroidism following non-convulsive status epilepticus.</p> <p>Case presentation</p> <p>Our patient was a 68-year-old Japanese woman. The results of endocrine testing after her first episode of non-convulsive status epilepticus suggested latent subclinical hypothyroidism: she had elevated thyroid-stimulating hormone with normal levels of free tri-iodothyronine and free thyroxine. On examination, a diagnosis of thyroid disorder was not supported by other test results and our patient remained untreated. A follow-up examination revealed that her thyroid-stimulating hormone levels had spontaneously normalized. When she consulted another doctor for confusion, the transient increase in thyroid-stimulating hormone levels following non-convulsive status epilepticus was mistaken for subclinical hypothyroidism, and unfortunately treated with levothyroxine. Our patient then experienced levothyroxine-induced non-convulsive status epilepticus.</p> <p>Conclusions</p> <p>In this report, we suggested possible mechanisms for latent hypothyroid-like hormone abnormality following epileptic seizures and the possibility of provoking epileptic seizures by administering levothyroxine for misdiagnosed subclinical hypothyroidism.</p

Changes in Seizure Frequency and Test-Retest Scores on the Wechsler Adult Intelligence Scale

Test-retest performance on the Wechsler Adult Intelligence Scale (WAIS) of two groups of adult epilepsy patients are presented and compared. In one group, Seizures Improved (SI) group, seizure frequency had decreased during the test-retest interval, and in the other group, Seizures Unimproved (SU) group, the number of seizures had either increased or stayed the same over the test-retest interval. The SI group showed a significant test-retest improvement on WAIS Verbal IQ, Performance 1Q, and Full Scale IQ, as well as on eight of 11 WAIS subtests. In comparison, the SU group showed significant increases only on the Performance IQ and Object Assembly subtest. Furthermore, differences between the two groups were observed in the pattern of test-retest changes seen on the Performance measures relative to the Verbal measures. The results suggest that change in seizure frequency is one of the factors associated with test-retest changes in the intellectual functioning of epilepsy patients. RÉSUMÉ Les rÉsultats obtenus À I‘Échelle de WAIS (Wechsler Adults Intelligence Scale) a partir d'une passation I (test) et d'une passation II (retest) chez deux groupes d'Épileptiques adultes sont prÉsentÉs et compares: (a) Dans un groupe la frequence des crises a diminue dur-ant I'intervalle “test-retest” (c'est a dire dans I'inter-valle separant la passation I (test) de la passation II (retest): Groupe des crises ameliorees (SI: seizures improved), (b) Dans l'autre groupe le nombre des crises au contraire a augmente ou bien est reste iden-tique au cours de I'intervalle “test-retest”: Groupe des crises non ameliorees (SU: seizures unimproved). Le groupe des “crises ameliorees” montre une amelioration significative tant sur le plan du QIV (quotient de I'echelle verbale), que du QIP (quotient de I'echelle performance) et du QIG (quotient global), ainsi que de 8 des subtests parmi les onze que contien I'echelle. En comparaison le groupe des “crises non ameliorees” ne montre une amelioration significative qu'au niveau du QIP et en particulier sur le subtest d'assemblage d'ob-jets (celui-ci faisant partie de I'echelle performance). De plus, on observe entre les deux groupes des differences du “type” des modifications entrainees par la situation “test-retest”, sur les rÉsultats obtenus a I'echelle performance et ceux obtensus a I'echelle verbale. Ces rÉsultats permettent de suggerer que, dans le fonctionnement intellectuel des sujets epileptiques, les changements dans la frequence des crises sont un des facteurs a mettre en correlation avec les changements observes a partir de la situation “test-retest”. RESUMEN Se compararon dos grupos de adultos con epilepsia por medio del rendimiento en dos tests de WAIS. En un grupo, la frecuencia de los ataques habia disminuido en el intervalo entre el primer test y el segundo [grupo con mejoria (SI)], mientras que en el otro el mimero de crisis no habia variado o habia au-mentado [grupo sin mejoria (SU)]. El grupo SI mostro una mejoria en laescala verbal CI, en la realizacion CI, en la escala total de CI y en los subtests WAIS. En comparacion, el grupo SU solo mostro un aumento significativo en la realizacion CI y en el subtest de Reunion de Objetos. Ademas, se observaron diferen-cias entre los dos grupos en lo que respecta a la prim-era y a la segunda prueba en la realizacion de las medidas verbales. Los resultados sugieren que los cambios en la frecuencia de los ataques juegan un papel en lo que respecta a funciÓn intelectual cuando se compara el primer WAIS con el segundo. ZUSAMMENFASSUNG Test und Retest Ergebnisse im WAIS von 2 Gruppen erwachsener Epileptiker werden dargestellt und ver-glichen. In einer Gruppe hatte die Anfallshaufigkeit wahrend des Test-Retest-Intervalls abgenommen– verbesserte Gruppe (SI)–und in einer anderen Gruppe war die Anfallshaufigkeit entweder gestiegen oder gleich geblieben wahrend des Test-Retest-Intervalls– unveranderte Gruppe (SU). Die SI-Gruppe zeigte signifikante Verbesserung zwischen Test und Retest im Verbal-IQ des WAIS, im Handlungsteil und im Gesamt-IQ ebenso wie in 8 von 11 WAIS Subtests. Im Vergleich hierzu zeigte die SU-Gruppe signifikante Verbesserung nur im Handlungs-IQ und im Objekte-zuordnungs-Subtest. Weiterhin wurden Unterschiede zwischen den beiden Gruppen im Muster der Test-Retest-Veranderungen im Verhaltnis des Handlung-steils zum Verbalteil bemerkt. Die Ergebnisse lassen vermuten, dalJ die Veranderung der Anfallshaufigkeit einer der Faktoren ist, der hinsichtlich der in-tellektuellen Funktion anfallskranker Patienten Bezie-hungen zu den Veranderungen des Test-Retest-Ergeb-nis aufweist.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65457/1/j.1528-1157.1981.tb04334.x.pd

In-home evaluation of efficacy and titration of a mandibular advancement device for obstructive sleep apnea

There is increasing evidence that mandibular advancement devices (MADs) can be an effective treatment for some patients with obstructive sleep apnea, a highly prevalent chronic disease. In this study, the objectives were to objectively assess the effectiveness of MAD therapy using a limited channel recorder, and to develop a model for identifying patients who may be appropriate for MAD therapy as the initial treatment option. Thirty patients were prospectively recruited and studied at two independent dentist offices and the participants’ homes. Subjects wore the ARES Unicorder for two nights before insertion of the MAD, and again when the dentist determined that the patient had reached the titration endpoint. Self-reported measures of depression, sleepiness, and quality of life were obtained pre- and posttreatment. The reviewer was blinded to the study status while the physiological signals were being visually inspected. Significant reductions in the apnea/hypopnea index (AHI), hypoxemia measures, and snoring level were observed posttreatment. Twenty-seven of the 30 (90%) patients had a posttreatment AHI (using a 4% desaturation for hypopneas) below a clinical cut-off of 10. All but one patient (97%) exhibited at least a 50% decrease in AHI or had a posttreatment AHI ≤ 10. Significant differences in body mass index, weight, and neck circumference in patients with posttreatment AHIs above and below a clinical cut-off of five were identified. The linear regression used to predict the posttreatment AHI using pretreatment data resulted in an R2 of 0.68. The model correctly predicted two patients who were unable to obtain a posttreatment AHI of 10 or less. This study was designed to demonstrate two models of collaboration between a dental sleep medicine specialist and a sleep medicine physician in the monitoring of a patient treated with a MAD. The outcome data suggest that the limited channel recording system can be used as an alternative to laboratory polysomnography to reduce the cost of MAD treatment, and to improve the quality and consistency of posttreatment patient care

The Dynamics of Sensorimotor Cortical Oscillations during the Observation of Hand Movements: An EEG Study

Background The observation of action done by others determines a desynchronization of the rhythms recorded from cortical central regions. Here, we examined whether the observation of different types of hand movements (target directed, non-target directed, cyclic and non-cyclic) elicits different EEG cortical temporal patterns. Methodology Video-clips of four types of hand movements were shown to right-handed healthy participants. Two were target directed (grasping and pointing) motor acts; two were non-target directed (supinating and clenching) movements. Grasping and supinating were performed once, while pointing and clenching twice (cyclic movements). High-density EEG was recorded and analyzed by means of wavelet transform, subdividing the time course in time bins of 200 ms. The observation of all presented movements produced a desynchronization of alpha and beta rhythms in central and parietal regions. The rhythms desynchronized as soon as the hand movement started, the nadir being reached around 700 ms after movement onset. At the end of the movement, a large power rebound occurred for all bands. Target and non-target directed movements produced an alpha band desynchronization in the central electrodes at the same time, but with a stronger desynchronization and a prolonged rebound for target directed motor acts. Most interestingly, there was a clear correlation between the velocity profile of the observed movements and beta band modulation. Significance Our data show that the observation of motor acts determines a modulation of cortical rhythm analogous to that occurring during motor act execution. In particular, the cortical motor system closely follows the velocity of the observed movements. This finding provides strong evidence for the presence in humans of a mechanism (mirror mechanism) mapping action observation on action execution motor programs