A Randomized Double Blind Controlled Trial Biology Essay


Facial palsy is a lesion of the facial nerve cranial nerve VII which can result in partial or full paralysis of one side of the face with preservation of facial sensation although some patients may report a feeling of numbeness (Pereira et al. 2011). Causes of the facial nerve palsy involving trauma, herpes zoster, polyneuritis, tumors, and diabetes mellitus. When it occurs suddenly and of unknown cause - as in about 70% of cases- it is called Bell's palsy (Teixeira et al. 2012). Facial palsy has annual incidence ranges between 23 to 35 cases for 100,000 people affecting both sexes mostly from 30 to 50 and 60 to 70 years old (Marques et al 2011). The facial motor fibers exit at the stylomastoid foramen to supply the muscles of facial expression. The facial nerve runs through the parotid gland to innervate the facial musculature through five main branches: the temporal, zygomatic, buccal, mandibular, and cervical branches (Mavrikakis, 2008). About 29% of cases with idiopathic facial nerve palsy has associated systemic symptoms including fever, headache, sore throat, or neck stiffness (Jaamaa et al. 2003). The majority of patients with facial palsy have a spontaneous clinical recovery, but about one-fifth of cases are left with sequelae (Jaamaa et al. 2003). On physical examination, the patient is unable to raise the eyebrow or tightly close the eyelid on the affected side. The nasolabial fold is typically absent, and the mouth may be drawn toward the unaffected side. Patients may drool from the affected side because of inability to keep the mouth closed (Mavrikakis, 2008). All these disfigurements of the face and impairment in the activities of daily living result in psychological, social and vocational handicap experienced by the patient with the facial neuromuscular dysfunction (VanSwearingen and Brach, 1996).

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Electrotherapy, massage, facial exercises and biofeedback are different physical therapy modalities that have been used for the treatment of Bell's palsy. Exercise therapy has been used more than other interventions (Teixeira et al. 2012). These physical therapy modalities aim to increase muscle and nerve function either through exercise or electrotherapy. Thermal methods and massage work by decreasing swelling and increasing blood flow to the affected tissues, increasing the amount of oxygen available to damaged, hypoxic tissues with the aim of promoting recovery (Lockhart, 2010). Laser therapy is a modality that can be used in the treatment of bell's palsy, it remains a painless therapeutic alternative, without side effects, which can be used for any type of patient including those who cannot use corticosteroids, such as diabetics and hypertensive patients (Quinn and Cramp, 2003).

Laser therapy has been used in regeneration of peripheral nerves with most favorable prognosis in both neurosensory and and neuromotor deficits (Ladalardo et al. 2001). Therapeutic laser has been found to be of value in the treatment of a variety of neural-related conditions such as trigeminal neuralgia, neuropathy, low back pain with sciatica, and herpes zoster (Kneebone; 2010). Laser therapy application produces both local and systemic effects which can enhance the nerve regeneration process (Kneebone; 2010). Moreover, Laser phototherapy improves recovery of the injured peripheral nerve and decreases posttraumatic retrograde degeneration of the neurons in the corresponding segments of the spinal cord. Investigative studies on the effects of low power laser irradiation 632.8 and 780nm on injured peripheral nerves of rats found to have protective immediate effects, which increase the functional activity of the injured peripheral nerve, preservation of the functional activity of the injured nerve, prevention or decreased degeneration in corresponding motor neurons of the spinal cord, and improving the axonal growth and myelinisation (Rochkind 2008). However, the evidence for the use of laser therapy in the acute and chronic Bell's palsy is still in need of further investigation (Quinn and Cramp, 2003).

Our present study aimed to investigate the effect of laser therapy on treatment of patients with Bell 's palsy and to compare between the high intensity laser therapy (HILT) and low level laser therapy (LLLT) in the treatment of patients with bell's palsy.



48 patients with facial palsy participated in the study. We excluded patients who had diseases of the central nervous system, sensory loss over the face, recurrence of facial paralysis and who were uncooperative during the study. The patients were randomly assigned into three groups.


Patients' evaluation was carried out before treatment, after six treatment sessions and after 12 treatment sessions to assess the grade of recovery using the facial disability scale (FDI) and the House-Brackmann Scale (HBS).

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Facial Disability Index Developed by Van Swearingen and Brach, to enhance the assessment of facial neuromuscular dysfunction beyond the impairment domain, this index provides a reliable measurement, with construct validity for evaluating the patients with facial nerve disorders (VanSwearingen and Brach, 1996).

House-Brackmann Scale Classified as a universal scale by the American Academy of Otolaryngology Committee of Disorders of the Facial Nerve, it was proposed and modified by House and Brackmann in 1985 (Pereira et al. 2011). Since then the HBS has extended to be the most accepted scale in assessment of facial nerve palsy because of its ease of use, and clinical sensitivity (Yen et al. 2003). This scale analyses the symmetry, synkinesis, stiffness and global mobility of the face. (Pereira et al. 2011).


LLLT Group 15 patients randomly assigned into this group received facial massage, facial expression exercise, and LLLT Gallium-Aluninum-Arsenide diode (GaAs) laser with a wavelength of 830 nm, average energy density of 10J/cm2, frequency of 3KHz, power density of 50mW, duty cycle 80% and a diameter of 1cm. For all cases, the laser in direct contact on the superficial roots of the facial nerve on the affected side (Figure 1) with time of application 4 min and 10 sec per point for 8 points and total energy of 80J for 12 sessions and two sessions per week.

HILT Group 17 Patients randomly assigned in this group received facial massage, facial expression exercise, HILT with energy density of 610 mJ/cm2/pulse, frequency of 3 KHz. The cases randomized in this group received HLLT on the superficial roots of the facial nerve on the affected side over the same points as the LLLT group but application time of 7 sec per point for 12 sessions and 2 sessions / week.

Control Group 16 Patients randomly assigned in this group received facial massage, and facial expression exercise.

Figure 1. Point of laser application in therapy for facial paralysis (adapted from Bernal 1993)

Outcome measures

Evaluation of the patients was carried out before treatment intervention, after six sessions, and after 12 sessions of the treatment to assess the grade of recovery using the FDI and the HBS.

Facial Disability Index This questionnaire has ten items that evaluate patients' physical and social aspects (mastication, deglutition, communication, labial mobility, emotional alterations and social integration). It uses a 100-point scale, with higher scores indicating less impairment and handicap (Pereira et al. 2011).

House-Brackmann Scale It is divided into six categories (normal, mild dysfunction, moderate dysfunction, moderately severe dysfunction, severe dysfunction and total paralysis) with grade 1 representing normal facial function in all areas and grade 6 representing total paralysis (Pereira et al. 2011).

Data Analysis

Friedman Test and Wilcoxon-signed ranks Test was used to compare the FDI and HBS scores within each group. Kruskal-Wallis Test and Mann-Whitney U-Test to compare the scores between the groups. The significance level was set to 0.05.


Friedman Test and Wilcoxon-signed ranks test showed statistical improvement after six sessions of treatment and after 12 sessions of the treatment in the HBS and in the components of FDI scores within each group with the greatest improvement found after 12 sessions (table 1 and 2). Kruskal-Wallis Test revealed no significant difference between the treatment groups in the HBS and in the components of FDI scores before treatment. After six sessions of the treatment, Kruskal-Wallis Test showed significant difference between the treatment groups in the HBS and FDI score (table 1).

The Mann-Whitney U-Test revealed that the greatest improvement in the components of FDI scores occurred in HILT group followed by LLLT group treated with the LILT group and the least improvement was in control group treated with massage and facial expression exercises only as shown in table 3. While for the HBS scores, the best effect was also for the HILT group and we did not find significant difference between LLLT group and control group after six treatment sessions (table 3).

Analysis of the HBS and FDI scores with Mann-Whitney U-Test after 12 session of the treatment showed significant difference between the treatment groups in the HBS and FDI scores (table 1). Moreover, we found the greatest effect in HILT group followed by LLLT group and the least effect was found in the control group (table 3).


In 1993 Bernal used mixed laser irradiation (904 nm diode GaAs and 632.8 nm helium/neon diode) to treat patients with facial paralysis. The lesion duration ranged from two days to15 weeks. He chose the case histories of 17 patients out of 50 patients and divided them into three groups. Group one consisted of patients who came for treatment within 15 days of the lesion. This group was further divided into those who had received medication and those with no previous treatment. Group two consisted of those presenting for treatment more than 15 days post-lesion. Finally, group three were patients who presented for treatment more than two years post-lesion. A major deficit of this study is that no objective scale was used to assess the patients' recovery, thus introducing an assessor bias. They concluded that low level laser light is anti-inflammatory, regenerative and produces cellular stimulation and that it is an excellent complementary medium for the recovery of facial paralysis, an excellent and painless therapeutic alternative without side-effects which can be used for any type of patient, including those who cannot use corticosteroids, such as diabetics and hypertensive patients. In addition, they considered it very important that there are no rules with regard to this illness and that spontaneous recovery should not be expected for a patient even though the literature reefers to 75% recovery within two weeks, because it is precisely this 25% which does not recover spontaneously with traditional medicines and therapies, that will retain a notable consequence of their paralysis, and that might have had a total recovery if they receive complementary treatment with laser within 15 days. Therefore, we consider that the laser must be taken into account as an excellent physical complementary therapy which allows recovery from facial paralysis, diminishing the possibility of side-effects due to corticosteroids, the actual results of the paralysis which are handled only with traditional therapy and above all the possibility of applying it to patients who cannot use corticosteroids. It also allows for the recovery in a noticeable manner.

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A study by Ladalardo et al; on four patients with bell's palsy treated with LLLT using GaAs diode laser of 780 nm, 50mW, continuous wave emission, spot size 3 mm, and total dosage 20 Joules per session, distributed to the peripheral trajectory of the injured nerve in a point by point contact mode. Altogether, 24 treatment sessions were performed in a period of 12 consecutive weeks twice a week. The lesion duration ranged from 23 days to 27 years. The outcome measures used was the HBS, pre- and post-treatment. Patient showed recovery of facial nerve condition and functional improvement ranging between one and three grades on the HBS.