Rajesh P. Poothrikovil

Snoring-Induced Nerve Lesions in the Upper Airway

The prevalence of habitual snoring is extremely high in the general population, and is reported to be roughly 40% in men and 20% in women. The low-frequency vibrations of snoring may cause physical trauma and, more specifically, peripheral nerve injuries, just as jobs which require workers to use vibrating tools over the course of many years result in local nerve lesions in the hands. Histopathological analysis of upper airway (UA) muscles have shown strong evidence of a varying severity of neurological lesions in groups of snoring patients. Neurophysiological assessment shows evidence of active and chronic denervation and re-innervation in the palatopharyngeal muscles of obstructive sleep apnoea (OSA) patients. Neurogenic lesions of UA muscles induced by vibration trauma impair the reflex dilation abilities of the UA, leading to an increase in the possibility of UA collapse. The neurological factors which are partly responsible for the progressive nature of OSAS warrant the necessity of early assessment in habitual snorers.

Predictive Value of Short-Term EEG Recording in Critically ill Adult Patients

ABSTRACT We assessed the EEG patterns and their prognostic significance in critically ill adult patients with encephalopathy, by digital EEGs lasting up to 1 hour. Of the 110 patients (age: 43.8 ± 19.4 years, male:female:1.6:1) studied, 32% had hypoxic ischemic encephalopathy (HIE), 17% severe infections, and 14.5% stroke. Observed EEG patterns were diffuse slowing (41%), low-voltage cerebral activity (LVCA, 18%), nonconvulsive status epilepticus (NCSE, 13.6%), and periodic abnormalities (9.1%). LVCA, age, Glasgow Coma Score (GCS) < 8, HIE, and modified Hockaday’s EEG grades of IV and V were associated with poor outcome (p < 0.005) at hospital discharge; generalized slowing was associated with a relatively good outcome (p = 0.003). On multivariate analysis, factors independently predictive of mortality were LVCA, older age, and poor GCS. In conclusion, LVCA and generalized background slowing were common EEG patterns among critically ill intensive care unit (ICU) patients with encephalopathy of varied etiologies. While LVCA was associated with a poor outcome, generalized background slowing predicted better prognosis. Conventional short-duration, bedside EEG studies could aid in the recognition of electrographic patterns of prognostic importance in facilities where continuous EEG monitoring is lacking.

Prevalence of Sleep-Disordered Breathing During Routine Electroencephalogram (EEG): A Hospital-Based Descriptive Study

Abstract Sleep-disordered breathing (SDB) in adults is a common condition that is associated with a range of medical problems including hypertension, cardiovascular complications, and increase of seizure frequency in susceptible individuals. Polysomnography (PSG) is considered the gold standard measure in the diagnosis of SDB. This is an observational study on the frequency of SDB in adult patients referred for routine EEG. We found that routine EEG was capable of detecting moderate to severe symptoms of SDB in 14% of adult patients (95% confidence interval = 8.1–19.9%). The state of sleep during a routine EEG recording could help in assessing a SDB pattern and could provide an opportunity for further diagnostic sleep consultation if the patient has not previously reported problems with sleep or if SDB was not considered by the referring physician. This study underscores the need for a practice approach to ensure that patients suffering from SDB are properly referred to a sleep specialist. In the context of this report, some training and experience in PSG can be an added advantage for EEG technologists in the detection of SDB.

The Usefulness of Nap Sleep Recording During Routine Electroencephalography: An Audit Study

OBJECTIVES A measure to increase the electroencephalogram (EEG) outcome includes a short period of nap sleep during a routine standard EEG with the aim of increasing its sensitivity to interictal abnormalities or provoking seizures. As part of an ongoing auditing of our EEG data, we aimed to investigate the contribution of nap sleep during routine outpatient department based EEGs requested for a variety of reasons. METHODS EEG data at the Department of Clinical Physiology at Sultan Qaboos University Hospital, Oman, from July 2006 to December 2007 and from January 2009 to December 2010 (total 42 months) were reviewed. The EEGs were for patients older than 13-years referred for possible epilepsy, blackouts, headache, head trauma, and other non-specified attacks. The recording period was between 20 to 40 minutes. Abnormalities were identified during waking and nap sleep periods. RESULTS A total of 2 547 EEGs were reviewed and 744 were abnormal (29.2%). Of those abnormal EEGs, nap sleep was obtained in 258 (34.7%) EEGs, and 39 (15.1%) showed abnormalities during nap sleep. Nineteen out of the 39 (48.7%) EEGs were abnormal during awake and nap sleep; and 20 (51.3%) were abnormal during nap sleep, which represented only 2.7% of the total abnormal EEGs (n = 744). CONCLUSIONS The contribution of the short nap sleep to the pickup rate of interictal abnormalities in EEG was minimal. We recommend the EEG service to include one cycle of spontaneous sleep EEG directed at patients with a history suggestive of epilepsy if their awake EEGs are normal.

Waveform Window #34: A Tip for Taps: Tactile-Induced Discharges in EEG

In epilepsy patients, focal or generalized paroxysmal activity or seizures have been found to be elicited by external stimulation, including visual, auditory, and touch. Hyperexcitability of certain cortical areas is responsible for reflex seizures and EEG paroxysms, photoparoxysmal response being a typical example. Benign childhood epilepsy with centrotemporal spikes (BECT or rolandic epilepsy) is a type of epilepsy of the somatosensory area and usually carries an excellent prognosis. A subgroup of BECT has been identified in which mechanical stimulation (i.e., the independent tapping of each finger bilaterally or the sole of the foot) elicits high-voltage evoked potentials in the parasagittal or contralateral centrotemporal regions, called “tactile rolandic discharges” or “tactile-enhanced discharges” (Langill and Wong 2003). This form of rolandic epilepsy is known as “benign epilepsy with extreme somatosensory evoked potentials (SEPs)” (Tassinari and De Marco 1985). In continuous EEG, these high-voltage SEPs can be seen as evoked spikes over the rolandic area which are timelocked to mechanical stimulation (tapping) (Manganotti et al. 1998; Rajesh et al. 2002). A few EEG samples of tapping-induced spikes are shown here from two BECT patients. The first patient is a 7-year-old girl with a history of nocturnal seizures (during night sleep with facial twitches) associated with hypersalivation. Her routine wakeful EEG, including hyperventilation and photic stimulation, was within normal limits. A sleep record was not obtained. Tapping the fingers of both hands and both feet independently induced spikes in the EEG as shown in Figures 1–3. The second patient is a 10-year-old boy who has a history of brief (<1 minute) focal motor seizures in the form of tonic posturing of upper limbs (usually left) with head/eye deviation and frothing of saliva, occasionally associated with impairment of consciousness and cyanosis. His wakeful record showed intermittent spikes from bilateral centrotemporal areas independently and was enhanced during his sleep record.

Atypical Presentation of Subclinical Rhythmic Electrographic Discharge of Adults (SREDA) in a Patient with Idiopathic Generalized Epilepsy

ABSTRACT. Subclinical rhythmic electrographic discharge of adults (SREDA) is considered a benign EEG pattern of uncertain significance, although it may closely resemble an electrographic seizure pattern. SREDA was first described by Westmoreland and Klass in 1981 as a distinctive rhythmic and rare EEG pattern primarily seen in older subjects. The typical pattern consists of sharp contoured, non-evolving 5 to 7 Hz theta rhythm with a widespread bilaterally synchronous distribution, but maximal over the parietal and posterior temporal regions. It usually lasts for a few seconds to several minutes without clinical association. Later in 1997, several unusual variants of SREDA were reported consisting of variations in frequency, morphology, topographic distribution, duration, and stage of alertness. We report SREDA in a patient with idiopathic generalized epilepsy which shows some atypical features (such as asynchronous onset, bifid waveforms, asymmetry, and fragmentation) and mimics a secondarily generalized partial seizure. It is important to successfully identify SREDA to avoid misdiagnosis and incorrect treatment. The technologists contribution is essential and valuable. EEG technologists and interpreters should be aware of typical and atypical features of SREDA and its wide spectrum.

Mystery Case: EEG FOLDer

A 20-year-old woman underwent sleep-deprived EEG (figure) for evaluation of possible seizure disorder. Interpret the EEG finding.

P6-5 The correlation between EEGs amplitude and interictal abnormalities

Results: The structure of intrinsic connectivity in both groups showed that the cerebellum has unidirectional connections with both left (dominant connection) and right BG. Unidirectional connections of the BG with SMA and SMA with cerebellum were present. In controls, the modulatory input decreased the relation of cerebellum with left BG and SMA with more pronounced symmetry of these connections. On contrary, PD patients showed an increased EC among cerebellum and both BG with more pronounced asymetry (stronger connection with left BG). Conclusion: Our findings indicate that the PD patients and controls use identical functional circuits to maintain the successful outcome in predictive motor timing behaviour, however the strength of EC differs between these two groups. Supported by Research Plan of Czech Ministry of Health MSM0021622404.