Task-specific walking training improves walking ability in an individual with vitamin B12 deficiency peripheral neuropathy: a case report

Introduction. A 32-year-old man, diagnosed with vitamin B12 deficiency neuropathy by means of laboratory parameters and electroneuromiography, and presented 3 month history of mild weakness of both lower limbs, associated with gait disturbances, fall history and fatigue . Method. After the pre-treatment evaluate, he started the exercise therapy program. To elucidate the therapeutic effects of exercise therapy program, the TUG, 10MWT and 6MWT was of exercise therapy program. Results. After 180-days of intervention, he showed an improvement on TUG test, totalizing an improvement of 31% when compared to the baseline time (5.1 seconds faster). On the 10MWT, the gait speed improvement presented an increased of 50% compared to the baseline speed. On the last walking distance assessment, at 180-days of intervention, the participant also showed an improvement of endurance, reaching 284 meters in 6 minutes of confortable walking. Conclusion. The described exercise therapy program for this patient resulted in improved walk ability after 180-days of intervention, including gait speed, gait endurance, ability to walk over longer distances and fall risk. basal (5,1 segundos más rápido). A las 10MWT, la mejora en la velocidad de la marcha mostró un aumento del 50% con relación a la velocidad inicial. En la última valoración de la distancia recorrida, a los 180 días de intervención, la participante también mostró mejoría en la resistencia, alcanzando los 284 metros en 6 minutos de marcha cómoda. Conclusión. El entrenamiento específico para retrasar la marcha descrito para este paciente dio como resultado una mejora en la capacidad para caminar después de 180 días de intervención, incluida la velocidad de la marcha, la resistencia de la marcha, la capacidad para caminar largas distancias y el riesgo de caídas.

of exercise therapy program. Results. After 180-days of intervention, he showed an improvement on TUG test, totalizing an improvement of 31% when compared to the baseline time (5.1 seconds faster). On the 10MWT, the gait speed improvement presented an increased of 50% compared to the baseline speed. On the last walking distance assessment, at 180-days of intervention, the participant also showed an improvement of endurance, reaching 284 meters in 6 minutes of confortable walking. Conclusion. The described exercise therapy program for this patient resulted in improved walk ability after 180-days of intervention, including gait speed, gait endurance, ability to walk over longer distances and fall risk.

INTRODUCTION
Vitamin deficiencies is a common nutritional disorder and, unless severe, they are often clinically unrecognized.
Vitamin B12 is an essential micronutrient required for normal cell function as it participates in a variety of critical processes including DNA, fatty acids and myelin synthesis 1,2 . The exact prevalence of vitamin B12 deficiency in the general population is unknown and the actual data is devived from a small survey, however, it may be a public health problem that could affects millions globally in both developing and developed countries [3][4][5]  Furthermore, the purpose of our study was to discuss and evaluate a exercise therapy program based on streghtening exercises plus task-specific walking training four times per week over 180 days as propose to improve its functionality.

Study Design and case presentation
This study was characterized as a case report and At the time of the study, the participant required assistance with activities of daily living, but was able to walk short distances with the aid of a Lofstrand crutch (Canadian crutch) and slowly climb the stairs one leg at a time using the handrail to provide stabilitiby and support. paramenters and electroneuromiography pattern (Table 1 and 2). The blood test and the electroneuromyography was performed at the same week of the beginning of exercise therapy program.

Exercise therapy program
The physiotherapy evaluation and treatment was The progression of the streghtening exercises was focused on increase the range of motion and, once resistence was introduced, the progression was made by increasing the weight machines.

Gait-related measures
The gait assessment was performed at the pretreatment baseline to verifity the walking ability before the proposed intervention, and was assessed at 90 and 180 days of intervention by means of the Timed Up & Go (TUG) test 12 , the 10-meter walk test (10MWT) 13 , and the 6-minute walk test (6MWT) 14

Timed Up & Go test
To perform the TUG test, the participant was asked to stand up from a 45cm-high-chair, walk 3 meters as quickly and safety as possible, turn around in a traffic cone, return to the chair and sit down, at the initial position. The required time to perform this activity was measured (in seconds). A total of three measurements were performed with an interval of 3 minute between measurements, with the best performance being considered for data analysis.
The TUG test was used to determine his permormance of multiple tasks, including sit-to-stand tansfers, gait speed, and postural stability. The time required for a subject to stand up from a chair, walk 3 meters, return to the chair and sit down has been used as an indicator of patients who are at risk of falling.

10-Meter Walk Test
The

6-Minute Walk Test
To execute the 6MWT, the participant was asked to walk for a 15-meter-long corridor during 6 minutes, at a comfortable speed. Standardized verbal encouragement was provide at minute intervals ("You are doing well", "Good job, continue!" And "Keep up the good work"). The 6MWT was used to determine gait endurance and ability to walk over longer distances. The participant walked for 6 minutes at comfortable speed and could rest when they felt unable to continue.

Outcomes analysis
The participant was assessed at the pre-treatment baseline and 90 and 180 days of the exercise therapy program. All collected data were entered into a Microsoft Excel spreadsheet. Tables and graphs were used to make comparisons among different periods of gait assessment in order to verify the effectivity of the exercise therapy program. For the TUG and 10MWT test, three measurements were performed and the best performance was used for data analysis.

Laboratory parameter
A review of her laboratory parameters at the pretreatment baseline showed lower values in hemoglobin (11.7g/dL) and hematocrit levels (34.5%) compared to normative values, which was an indicative of a mild anemia. There was also a decrease in Vitamin B12 level, proving a severe hypovitaminosis. The participant presented 50pg/mL of B12, while the normative value for vitamin B12 is between 211 and 911pg/mL, as shown in Table 1.

Gait parameters
The measurements of the TUG, 10WMT and 6MWT from pre-treatment baseline, 90 and 180-days of proposed intervention are compiled, as shown in Table 3.
The assessment of walking ability at the pre-treatment baseline showed that the time required on TUG test was   and affect the quality of life of people with disabilities, thus, an effective approach aiming to reduce gait alterations is essential. Many interventions have been designed to improve walking function, however, an accumulating body of evidence reveals that task-specific training is effective in improving lower limb activities in general and walking outcomes specifically [16][17][18][19] . In this therapy the patients practice context-specific motor tasks and focus on improvement of performance in functional tasks through goal-directed practice and repetition 16 . However, "taskspecific training" is an generic term used to describe several approaches including task-orientated training and repetitive task training 16,18,19 .
The results shown here are consistent with our hypothesis that strengthening exercises plus task-specific walking training may act improving the patient functionality against the gait alterations in a young adult patient who was diagnosed with vitamin B12 deficiency neuropathy. So far, there is plenty of evidence indicating that the brain is able to reorganize itself in response to change in behavioural demands through neuroplasticity 16,20 , therefore, the task-specific training can restore function by using nonaffected or supplementary parts of the brain (for detail review 21 ). Studies reveal that task-specific training shows effective results in diferents neurological conditions, as stroke, traumatic brain injury, Parkinson's disease, spinal cord injury and brachial plexus injury, however, to the best of our knowledge, the tast-specific training have never been used to analyze the therapeutic effects on gait ability in vitamin B12 deficiency peripheral neuropathy. More studies need to be performed in order to establish the effectiveness of tast-specific walking training in peripheral neuropathy.
The gait speed was measured in two types of tests and, the data obtained on the 6MWT showed a lower speed compared to that results on the 10MWT. Thus, using the gait speed data obtained on the 10MWT, the individual was classified as limited community ambulator at the baseline assessment and, at the end of the exercise program he was classified as full community ambulator. On the other hand, using the gait speed data colected on the 6MWT, the individual was classified as household ambulator at the baseline assessment and limited community ambulator at the end of the exercise program 15 . Suggesting that 10MWT and the 6MWT may measure different aspects of walking function in patients with peripheral neuropathy.

CONCLUSION
The results presented here suggests that a streghtening exercises plus task-specific walking training could be an effective form of exercise therapy program for improving mobility in patients with peripheral neuropathy.
This program significantly improved walk ability, including gait speed, gait endurance, ability to walk over longer distances and fall risk.
Due to the case report design of the present study, we could not compare the effect of this particular exercise therapy program to a control group. Further research with larger sample sizes is required before recommendations for practice can be made, hence, a randomized controlled trial is warranted.