This site welcomes original publications, review articles, case records in the field of neurology, psychiatry, neuroradiology, neuropathology, and neurosurgery
The author: Professor Yasser Metwally
http://yassermetwally.com
INTRODUCTION
January 11, 2012 — Neuronal migration disorders are an important differential diagnosis to be considered in the evaluation of intractable epilepsy. Though the underlying causative factors which govern their development are many and varied, genetic factors have been found to be contributory in a few forms of these disorders. An X–linked association with lissencephaly has been discovered and there are a few families described till now with this entity.
Neuronal migration disorders are often found as the underlying cause of intractable epilepsy and mental retardation. Though the genetic basis of these malformations has been established in some forms of these disorders, X- linked lissencephaly and its associations have only recently been documented.
Neuronal migration disorders commonly present in childhood as intractable epilepsy and mental subnormality. The proliferation and differentiation of the neuronal precursors in the periventricular germinal matrix and their migration to the cortical mantle begins in the sixth gestational week. The radial glial fibers form the framework on which the nerve cells migrate.[1] The migrating neuroblasts which initially maintain affinity with the radial glial fibers through specific glycoproteins, detach themselves on approaching the cortex. They subsequently interact with the dendrites and axon terminals of other neuroblasts and engage in layer formation. The migration of the neuroblasts occurs in an ‘inside-out’ fashion in that the last cells migrate to the superficial layers of the cortex.[2]
Abnormalities of neuronal migration at any stage give rise to a group of congenital malformations comprising lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. Cytoarchitectonic analysis of the agyric cortex suggests a disorder of neuronal migration between the 11th and 13th fetal week while the pachygyric cortex shows attenuated and later disorder acting in the Rakic and Sidman stage IV after the 13th fetal week. Therefore, there is a gradient from the agyric to the normal six-layered cortex. Polymicrogyria presumably results from events after the 16th fetal week when the migration has terminated.[3] When the layer of misplaced neurons is thinner, the later migrating neuroblasts pass through it to reach the cortex and form the double cortex. Sometimes when there is arrest of migration right at the place of origin, diffuse periventricular heterotopias occur. The latter two conditions are often associated with normal gyri.
The possible causes of neuronal migration disorders may be acquired or genetic. The acquired etiologies include cytomegalovirus and toxoplasmosis infections, exposure to toxins such as ethanol, carbon monoxide, isotretinoic acid and cytotoxic drugs, effects of ionizing radiation and intrauterine circulatory disturbances.[4] Classical lissencephaly occurring either as an isolated lissencephaly sequence or in association with the Miller-Dieker syndrome (MDS), has been found to be associated with visible or submicroscopic deletions of chromosome 17p 13.3 (in upto 90% of MDS patients).[4,5,6] The identification of unbalanced translocations and inversions is of particular importance because of the risk of recurrence, while deletions and ring chromosomes are mainly sporadic. Syndromes featuring lissencephaly type II are most probably autosomal recessively inherited though the location of the gene and the nature of the mutations are not known.
Two distinct X-linked malformations of neuronal migration have been described, namely X-linked lissencephaly (XLIS) and subcortical band heterotopia (SBH) localized to chromosome Xq22.3, and bilateral periventricular nodular heterotopia which is mapped to chromosome Xq28. XLIS has been delineated as a specific genetic syndrome with manifestations in males as lissencephaly and in females as SBH. The clinical features of XLIS are similar to the classical form of lissencephaly. Patients with SBH are mostly females and manifest with mental retardation, behavior problems and epilepsy. This skew towards females reflects the potential lethality of the mutation in the affected males. XLIS has so far been documented in only 7 families.[7,8,9,10,11,12] The existence of XLIS has been supported by chromosomal studies which show an apparently balanced denovo X – autosomal translocation in the gene at Xq22.3.[13] Though the nature of the product of the XLIS gene is not known, the phenotypic variability in the different sexes could be based on the complete absence of the gene product in males and functional mosaicism in females.
X-linked lissencephaly is a rare syndrome and needs documentation by clinical and molecular biological tools. Awareness and detection of this entity prenatally is important for preventive neurology and genetic counseling.
References
1. Barkovich AJ, Gressens P, Evrard P. Formation, maturation and disorders of brain neocortex. AJNR Am J Neuroradiol 1992;13:423-46.
2. Rakic P. Specification of cerebral cortical areas. Science 1988;241:170-6.
3. Jellinger K, Rett A. Agyria – pachygyria (lissencephaly syndrome). Neuropaediatrics 1976;7:66-91.
4. Barth PG. Disorders of neuronal migration. Can J Neurol Sci 1987;14:1-16.
5. Dobyns WB, Truwit CL. Lissencephaly and other malformations of cortical development: 1995 update. Neuropaediatrics 1995;26:132-47.
6. Dobyns WB, Reimer O, Carazzo R, et al. Lissencephaly: a human brain malformation associated with deletion of the L1S1 gene located at chromosome 17p13. J Am Med Asso 1993;270:2838-42.
7. Pavone L, Gullotta F, Incorpora G, et al. Isolated lissencephaly: report of four patients from two unrelated families. J Child Neurol 1990;5:52-9.
8. Berry-Kravis E, Israel J. X-linked pachygyria and agenesis of corpus callosum: evidence for an X chromosome lissencephaly locus. Ann Neurol 1994;36:229-33.
9. Pinard J-M, Motte J, Chiron C, et al. Subcortical laminar heterotopia and lissencephaly in two families: a single X linked dominant gene. J Neurol Neurosurg Psychiatry 1994;57:914-20.
10. Scheffer IE, Mitchell LA, Howell RA, et al. Familial band heterotopias; an X-linked dominant disorder with variable severity (abstract). Ann Neurol 1994;36:511.
11. Puche A, Rodriguez T, Domingo R, et al. X-linked subcortical laminar heterotopia and lissencephaly: a new family. Neuropaediatrics 1998;29:276-8.
12. Berg MJ, Sciffito G, Powers JM, et al. X-linked female band heterotopia – male lissencephaly syndrome. Neurology 1998;50:1143-6.
13. Dobyns WB, Andermann E, Andermann F. et al. X-linked malformations of neuronal migration. Neurology 1996;47:331-9.
December 13, 2011 — Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disease that has an incidence of approximately 1 in 6,000 to 10,000 live births and a carrier frequency of about 1 in 50 (Ogino and Wilson, 2004; Rodrigues et al, 1995). It is the second most common lethal autosomal recessive disease in humans, after cystic fibrosis, and the most common fatal neuromuscular disease diagnosed in children under the age of eighteen.
SMA is divided into three main groups based on age of onset and the clinical severity or prognosis of the disease. However, all subtypes are biologically similar and map by linkage analysis to the long arm of chromosome 5. SMA type I (Werdnig-Hoffmann Disease) is the infantile onset form which usually manifests before 6 months of age. Patients with this subtype typically have profound weakness early in life and are sometimes described as "floppy infants" with a loss of deep tendon reflexes and an inability to sit upright or walk. These patients usually have early death due to respiratory failure. There are some reports of babies presumed to have sudden infant death syndrome (SIDS) who were found to have an absence of the SMN1 gene and likely represent infants who died of respiratory failure due to SMA (Ogino and Wilson, 2004). Type II SMA (intermediate or juvenile) usually presents between 6 and 18 months of age, and patients can usually sit unaided, but not walk without assistance. Type II patients usually survive into adolescence or adulthood. Type III SMA (Kugelberg-Welander Disease) is the mildest form of SMA and usually manifests after 12-24 months of age. Patients with this subtype walk independently and typically have normal survival. SMA type IV (adult-type) has been a controversial entity (Brahe et al, 1995; Zerres et al, 1995), but is defined by some as SMA presenting after 30 years of age. The existence of type IV is questioned by some due to the fact that SMN1 is not homozygously absent in some of these patients, and therefore it is unclear if these represent SMN1-unrelated SMA or small intragenic mutations in SMN1.
Table 1. Types of Spinal Muscular Atrophy
The separation of SMA into distinct subtypes has also been correlated with SMN2 copy number (Mailman et al, 2002). With a decrease in the number of SMN2 gene copies, there appears to be an increase in the severity of weakness, with more patients presenting with type I SMA if there are one or two SMN2 gene copies (Mailman et al, 2002). Patients with three to four copies of the SMN2 gene appear more likely to have milder disease, such as SMA type III. It is important to realize that all patients with SMA will have at least one copy of SMN2, because the complete loss of SMN would be an embryonic lethal condition and not result in a live birth. Thus, it appears that SMN2 copy number has an important modifying effect on the disease severity and prognosis.
Molecular Pathogenesis:
SMA is most often (about 95% of cases) caused by a homozygous absence of the SMN1 gene. "Absence" can be due to either gene deletion (typically a large deletion that includes the whole gene) or gene conversion to SMN2. There is also a high rate of de novo gene deletions, which could explain the high carrier frequency of SMA (Ogino and Wilson, 2002).
The SMN genes give rise to a 38 kD SMN protein. The protein is thought to have a variety of functions, including splicing, ribosome formation, gene transcription, and possibly motor neuron specific actions, such as a role in neurite outgrowth and axonal transport (Briese et al, 2005). The SMN gene exists as 2 highly homologous copies in an inverted, duplicated region of the gene. The telomeric copy is referred to as SMN1, and the centromeric copy is referred to as SMN2. The 2 copies of SMN differ by a total of 5 nucleotide base pairs (one in exon 7, exon 8, and intron 6; two in intron 7). Although none of the single base pair differences cause a change in the amino acid sequence (i.e. translationally silent), the change in exon 7 influences the splicing pattern, such that it diminishes the ability of the SF2/ASF (serine/arginine rich) protein to bind to SMN2, and thereby reduces the recognition of SMN2 exon 7 by the spliceosome. This results in a truncated SMN protein that is less stable and cannot fully substitute for the full-length SMN protein from the SMN1 gene. The result is that there is insufficient full-length SMN protein for the survival and maintenance of motor neurons.
Molecular diagnosis of SMA can be done via targeted mutation analysis using PCR with restriction fragment length polymorphism (PCR-RFLP), which is able to detect the homozygous absence of SMN1 (van der Steege G. et al, 1995) as described above. Other diagnostic methods include sequencing of the SMN gene copies to find small intragenic mutations and linkage analysis for patients in whom neither a sequence variant nor an SMN1 gene deletion can be identified.
Also as mentioned, one drawback to the PCR-RFLP assay method is that it will not detect SMA carriers. To detect carriers, SMN1 dosage analysis must be done; this is typically determined by quantitative competitive PCR-RFLP using a stable diploid reference gene, such as the cystic fibrosis transmembrane regulator (CFTR) gene (McAndrew et al, 1997).
Recent developments:
Currently, there is no cure for SMA. It is likely that new therapeutic treatments will be available in the near future. Many promising agents are under investigation and going to clinical trials. Many of these therapeutic modalities involve increasing the transcription of the SMN2 gene in order to get more full-length SMN transcript, correcting the splicing defect to include exon 7, stabilizing the SMN protein, and repairing degenerating neurons through stem cell therapy. Some of these therapeutic agents include histone deacetylase inhibitors, sodium butyrate (Chang et al, 2001), short oligonucleotides (Skordis et al, 2003) and gene therapy.
If a cure becomes available or if a therapeutic agent is able to help these patients, it will be important to identify patients early to start treatment before anterior motor neurons degenerate. One group has proposed newborn screening for SMA using DNA extracted from blood spots assessed by real-time multiplex PCR analysis to identify patients with an absence of SMN1 exon 7 (Pyatt and Prior, 2006). This approach delivers an analytical sensitivity and specificity of 100% in pilot studies. A newborn screening test would require automated DNA extraction to screen large number of samples. The proposed test on newborns would not detect compound heterozygotes or deliver dosage analysis for patients who may develop a less severe phenotype because of additional SMN2 gene copies.
Until a cure or treatment is available for these patients, management will continue to involve preventative care with immunizations and early treatment of any respiratory infections due to the risk of severely compromising respiratory function.
Briese M, Esmaeili B, Sattelle DB. Is spinal muscular atrophy the result of defects in motor neuron processes? BioEssays 2005; 27:946-957.
Chang JG, Hsieh-Li HM, Jong YJ, Wang NM, Tsai CH, Li H. Treatment of spinal muscular atrophy by sodium butyrate. PNAS 2001;98(17):9808-9813.
Mailman MD, Heinz JW, Papp AC, Snyder PJ, Sedra MS, Wirth B, Burghes AHM, Prior TW. Molecular analysis of spinal muscular atrophy and modification of the phenotype by SMN2. Genetics in Medicine 2002:4(1):20-25.
McAndrew PE, Parsons DW, Simard LR, Rochette C, Ray PN, Mendell JR, Prior TW, Burghes AHM. Identification of Proximal Spinal Muscular Atrophy
Carriers and Patients by analysis of SMNt and SMNc Gene Copy Number. Am J Human Genetics 1997; 60:1411-1422.
Ogino S and Wilson RB. Genetic Testing and risk assessment for spinal muscular atrophy (SMA). Human Genetics 2002; 4(1):15-29.
Ogino S and Wilson RB. Spinal Muscular Atrophy: molecular genetics and diagnostics. Expert Rev. Mol. Diagn. 2004; 111:477-500.
Pyatt RE, Prior TW. A feasibility study for the newborn screening of spinal muscular atrophy. Genetics in Medicine 2006;8(7): 428-437.
Rodrigues NR, Owen N, Talbot K, Ignatius J, Dubowitz V, Davies KE. Deletions in the survival motor neuron gene on 5q13 in autosomal recessive spinal muscular atrophy. Human Mol Genet 1995;4:631-634.
Skordis LA, Dunckley MG, Yue B, Eperon IC, Muntoni F. Bifunctional antisense oligonucleotides provide a trans-acting splicing enhancer that stimulates SMN2 gene expression in patient fibroblasts. PNAS 2003; 100 (7):4114-4119.
van der Steege G. Grootscholten PM, van der Vlies P, Draaijers TG, Osinga J, Cobben JM, Scheffer H, Buys CH. PCR-based DNA test to confirm clinical diagnosis of autosomal recessive spinal muscular atrophy. Lancet 1995;345(8955):985-986.
Similarly, since this assay does not quantitate gene copy number, it cannot detect heterozygous deletion carriers since the normal gene copy will yield a PCR product.
December 13, 2011 — Hypertensive encephalopathy, described in 1928 by Oppenheimer and Fishberg (8), is a specific clinical syndrome characterized by acute neurologic change in the setting of sudden and/or prolonged hypertension that overcomes the autoregulatory capacity of the cerebral vasculature. It is a subset of the more generalized reversible posterior leukoencephalopathy syndrome (9,10). At clinical examination, the neurologic manifestations include headache, nausea, vomiting, seizures, convulsions, visual changes, confusion, and coma (11). Although myocardial, renal, hepatic, and hematologic manifestations exist, they are less easily identified. Treatment of hypertension often leads to complete neurologic recovery. Untreated hypertension can lead to progressive central nervous system failure with intracranial hemorrhage, irreversible cerebral infarction, coma, and death (12).
Hypertensive encephalopathy occurs most commonly in adult patients who have an abrupt elevation in systemic blood pressure. It often occurs in association with essential or severe chronic hypertension, renal disease, collagen-vascular disease, mixed connective-tissue disorders, endocrine abnormalities, preeclampsia-eclampsia syndrome, and/or use of immunosuppressive medications (most notably cyclosporine) (9,13–20).
Figure 1. Reversible hypertensive encephalopathy-induced cerebral edema. Initial transverse T2-weighted image (2,500/90) demonstrates bilateral parietal and occipital areas of high signal intensity (arrows).
Hypertensive encephalopathy is rare in the pediatric population. When present, it is usually related to renal diseases such as acute glomerulonephritis, renal vascular hypertension, or chronic renal failure from any cause (21–23). As in the adult population, hypertensive encephalopathy may also occur with an acute abrupt elevation in blood pressure. Since there are age-dependent normal ranges of blood pressure in pediatric patients, the requirement for blood pressure to exceed a particular value is inappropriate as the sole criterion for the diagnosis of hypertension. The diagnosis of hypertensive encephalopathy should be made in children who demonstrate a change in neurologic function that is coincident with an elevation in blood pressure above the age-dependent normal range and in whom other causes of acute encephalopathy have been excluded (21).
Physiologic autoregulatory modulation of precapillary arteriolar vasomotor tone maintains a constant cerebral perfusion pressure despite fluctuations in systemic blood pressure (24,25). Perivascular sympathetic tone is increased in the setting of hypertension and serves to protect the brain from increased intravascular pressure. Initial investigators (26–28) postulated that hypertensive encephalopathy was the result of uncontrolled autoregulatory vasoconstriction that led to hypoperfusion, with focal areas of ischemia and infarction. Although some controversy still persists about the exact mechanism that leads to hypertensive encephalopathy, it is now generally believed that cerebral vascular vasodilatation caused by high-pressure autoregulatory failure is the pathophysiologic mechanism (1,4,13,20,24,29,30). Increased vascular permeability results in cerebral edema due to extravasation and transudation of protein and fluid into the brain parenchyma. The relative paucity of sympathetic innervation to the posterior circulation compared with that of the anterior circulation likely accounts for the resultant distribution of changes with a preponderance of posterior circulatory changes (25,26,31).
Neurologic MR imaging and computed tomographic findings consistent with those of hypertensive encephalopathy have been described previously; these include reversible and predominantly posterior temporal, parietal, and occipital edema that is preferentially located in the paramedian subcortical white matter. In cases of mild hypertension, the findings are usually supratentorial; in cases of more severe hypertension, similar changes are noted in the basal ganglia, cerebellar hemispheres, and brainstem (1–4).
Neurologic findings at follow-up imaging reflect the clinical outcome. With control of hypertension and reversal of symptoms, the imaging findings normalize. If left untreated, hypertension leads to progressive neurologic deterioration, and images demonstrate progressive areas of abnormal signal intensity that reflect hypertensive encephalopathy–induced ischemia, infarction, and/or hemorrhage.
Early recognition of hypertensive encephalopathy as posterior parietal parasagittal areas of high signal intensity on T2-weighted images and normal signal intensity on diffusion-weighted images allows the institution of appropriate antihypertensive treatment when the potential for complete neurologic recovery still exists. Failure to recognize this syndrome may lead to progressive, irreversible neurologic deterioration with cerebral ischemia and infarction. In this patient population, it can also lead to alterations in treatment regimens, with the potential to discontinue the use of chemotherapeutic agents that have been proved to be highly efficacious in the treatment of such disorders.
Schwartz RB, Jones KM, Kalina P, et al. Hypertensive encephalopathy: findings on CT, MR imaging and SPECT imaging in 14 cases. AJR Am J Roentgenol 1992; 159:379-383.[Abstract]
Kingma A, Tamminga RY, Kamps WA, Le Coultre R, Saan RJ. Cerebrovascular complications of L-asparaginase therapy in children with leukemia: aphasia and other neuropsychological deficits. Pediatr Hematol Oncol 1993; 10:303-309.[Medline]
July 6, 2011 — Cerebellar signs
Video 1. Cerebellar signs
Metwally, MYM: Textbook of neuroimaging, A CD-ROM publication, (Metwally, MYM editor) WEB-CD agency for electronic publication, version 12.2 April 2011 [Click to have a look at the home page]
July 4, 2011 — Facial paralysis is a disfiguring disorder that has a great impact on the patient. Facial nerve paralysis may be congenital, neoplastic, or result from infection, trauma, toxic, or iatrogenic causes. The most common cause of unilateral facial paralysis is Bell palsy, also known as idiopathic facial paralysis. Bell palsy is thought to account for approximately 60-75% of acute unilateral facial paralysis.
In 1550, Fallopius noted the narrow lumen in the temporal bone through which a part of the seventh cranial nerve passes. In 1828, Charles Bell made the distinction between the fifth and seventh cranial nerves, he noted that the seventh nerve was mainly involved in the motor function of the face and the fifth nerve was mainly concerned with the sensory perception of the face.
Even today, controversy still surrounds the etiology and treatment of Bell palsy. Clinical features of Bell palsy that may help distinguish this from other causes of facial paralysis include sudden onset of unilateral facial paralysis (less than 48 hours), absence of signs and symptoms of CNS disease, and absence of signs and symptoms of ear or posterior fossa disease.
The majority of patients who suffer from Bell palsy have neurapraxia or local nerve conduction block. These patients are likely to have a prompt and complete recovery of the nerve. Patients with axonotmesis, with disruption of the axons, have a fairly good recovery but it is usually not complete. The risk factors thought to be associated with a poor outcome in patient’s with Bell palsy include (1) age greater than 60 years, (2) complete paralysis, and (3) decreased taste or salivary flow on the side of paralysis (usually 10-25% compared to the patient’s normal side). Other factors thought to be associated with poor outcome include pain in the posterior auricular area and decreased lacrimation.
Patients generally have a good prognosis; approximately 80-90% of the patients will recover without noticeable disfigurement within one and a half to three months. Patients aged 60 years or older have approximately a 40% chance of complete recovery and have a higher rate of sequelae. Patients younger than 30 years have a 10-15% chance of partial recovery and sequelae. If no recovery occurs by 4 months, then the patient is more likely to have sequelae from the disease, which include synkinesis, crocodile tears, and rarely hemifacial spasm.
Synkinesis is an abnormal contracture of the facial muscles while smiling or closing the eyes. It may be mild and result in slight movement of the chin when the patient blinks, eye closure with smiling, or contracture around the mouth while blinking. Crocodile tears are observed; patients shed tears while they eat.
Facial spasm is a very rare complication of Bell palsy. It occurs as tonic contraction of one side of the face. Spasms are more likely to occur during times of stress or fatigue and may occur during sleep. This condition may occur secondary to compression of the root of the seventh nerve by an aberrant blood vessel, tumor, or demyelination of the nerve root. It occurs most commonly in the fifth and sixth decades, and sometimes the etiology is not found. The presence of progressive facial hemispasm with other cranial nerve findings indicates a possibility of a brainstem lesion.
Diabetics are 30% more likely to have only partial recovery; recurrence of Bell palsy is also more common among diabetics. Bell palsy accounts for only 23% of bilateral facial paralysis. The majority of patients with bilateral facial palsy have Guillain-Barré syndrome (GBS), sarcoidosis, Lyme disease, meningitis (neoplastic or infectious) or bilateral neurofibromas in patient’s with Neurofibromatosis 2. Recurrent Bell palsy occurs in 10-15% of patients. It may occur on the ipsilateral or contralateral side of the initial palsy. It is usually associated with a family history of recurrent Bell palsy. Approximately 30% of patients with recurrent ipsilateral facial palsy were found to have tumors of the seventh nerve or parotid gland. Patients with recurrent ipsilateral facial palsy should undergo MRI or high-resolution CT to rule out neoplastic or inflammatory (multiple sclerosis or sarcoidosis) cause of recurrence.
Synkinesis
Synkinesis means “simultaneous movement.” Synkinesis occurs secondary to abnormal facial nerve regeneration after Bell’s palsy or instances where the facial nerve has been cut and sewn back together. The facial nerve fibers can implant into the different muscles in cases of bells palsy. Additionally, when the nerve is re-sewn, the facial nerve fibers oftentimes reconnect to the wrong nerve group causing undesired and simultaneous facial movement. Synkinesis, therefore, results in abnormal synchronization of facial movement where muscles, other than those intended contract together during a particular movement pattern.
Synkinesis does have some predictable facial muscle patterns and can have a range of severities. It is important to separate true paralysis and synkinesis. If patients have good facial tone and some visible movement, then they do not have full paralysis and many of their abnormal facial movements are a result of synkinesis. The most common effect of synkinesis is when patients experience eye closure during a smile. The eyes tend to twitch or close while the patient is trying to smile or laugh. Synkinesis can also be a powerful cause of inability of the corner of the mouth to move upwards in patients who have regained their facial tone. Patients usually just think that their face is not moving; however, in many patients their inability to smile is secondary to synkinetic (simultaneous) movement of muscles that droop the corner of mouth (depressor anguli oris, platysma, and mentalis muscles) and muscles that elevate the area (zygomaticus major and minor). Other patterns of synkinesis are dimpling in the chin and narrowing of the eyes. In addition to these abnormal movement patterns, synkinesis also causes increased muscle tone with spasm, contracture and tightness of the neck bands and cheeks.
Prevention of Synkinesis
There are some ways to reduce the risk of developing synkinesis after bells palsy. The Chevalier’s method is one of the more common ways of using a “facial re-education” method to prevent synkinesis and educate your facial muscles. Patients are encouraged to maintain facial symmetry by keeping the normal side of face up when speaking, chew food with eyes open, avoid gum, wear sunglasses to prevent squinting, massage the intraoral buccal area, always align face to block associated movement, Stretch orbicularis oculi (eye muscles). Patients are also encouraged to really work on having slow and symmetric movements. The key aspect of prevention is the first 3-4 months after injury or Bell’s palsy. It is important to note that some studies have shown that electrical stimulation can result in increased likelihood of developing synkinesis.
Management of Synkinesis
Once synkinesis has occurred, treatment relies on three distinct modalities: neuromuscular retraining (physical therapy), Botox (botulinum toxin) and surgery. Treatment of synkinesis can be initiated at any time after its occurrence. This may be even years after a patient has suffered Bell’s palsy or facial paralysis.
Neuromuscular retraining and physical therapy of synkinesis is very different than what is performed for other medical problems such as back pain and orthopedic injuries. Facial neuromuscular retraining is more comparable to a vocal therapist that is treating a singer who has hoarseness or poor mechanics. Facial neuromuscular retraining is primarily focused on coordinating appropriate facial muscle movements. This is achieved by inhibiting the activity of the abnormal movement patterns resulting in “auto-paralysis” of unwanted muscles.
The muscles that are contracting abnormally are first identified. Muscles that are contracting out of sequence are inhibited. Small steps are usually taken in order to gradually retrain the muscles as there needs to be significant changes at the neurologic (brain) level for success. Electrical stimulation is avoided as it tends to increase the overactive muscles. Muscles that are extremely overactive in the cheek and neck are actively massaged and stretched. Patients are discouraged from undergoing strong muscle strengthening exercises as again this is more about re-coordination rather than stimulation. Patients are also taught how to elevate the upper eyelids during eating to reduce the eye synkinesis. Ninety percent of the therapy is done with the patient at home. The therapist at the Facial Paralysis Institute typically teaches the patients the appropriate home exercises. Other treatment modalities will focus on mirror and video exercises.
The second mode of therapy for synkinesis is BOTOX (botulinum toxin-A). Botox is used in conjunction with facial neuromuscular therapy in most cases. Botox works by reducing the activity of the muscles that are overactive or uncoordinated. Most common areas of injection are eye muscles (orbicularis), neck bands (platysma), and chin dimpling (mentalis). We also utilize it occasionally for very tight cheek if therapy has been unsuccessful. Botox can also be used to symmetrize the face by reducing the activity of certain muscles on the normal side of the face such as: forehead, lower lip depressors (depressor anguli oris) and crow’s feet (orbicularis).
The final modality for synkinesis is surgery. Surgery is utilized only when physical therapy and botox have been unsuccessful in obtaining the desired results. Static suspension of the corners of the mouth, surgical manipulation of the neck bands and blepharoplasty (eyelid surgery) are commonly utilized to address these concerns. During your consultation, all options are discussed at length if you are an appropriate candidate.
