Mobility issues associated with falls and freezing of gait have a devastating impact in the lives of PD patients. Fear of falling in itself can have an incapacitating effect in PD patients and can result in social seclusion leaving patients largely isolated leading to depression. Immobility can also lead to osteoporosis which in-turn facilitates future fracture development. This then becomes a vicious circle with falls leading to immobility and immobility facilitating future falls. Hip fractures from falls are the most common form of fracture among PD patients. Fractures increase treatment costs associated with health care expenditures in PD. Also, when gait is affected it often heralds the onset of Lewy body dementia.

Persons suffering from peripheral neuropathy experience numbness and tingling in their hands and feet. This can cause ambulation impairment, such as trouble climbing stairs or maintaining balance. Gait abnormality is also common in persons with nervous system problems such as cauda equina syndrome, multiple sclerosis, Parkinson's disease, Alzheimer's disease, myasthenia gravis, normal pressure hydrocephalus, and Charcot–Marie–Tooth disease. Research has shown that neurological gait abnormalities are associated with an increased risk of falls in older adults.

Orthopedic corrective treatments may also manifest into gait abnormality, such as lower extremity amputation, post-fracture, and arthroplasty (joint replacement). Difficulty in ambulation that results from chemotherapy is generally temporary in nature, though recovery times of six months to a year are common. Likewise, difficulty in walking due to arthritis or joint pains (antalgic gait) sometimes resolves spontaneously once the pain is gone. Hemiplegic persons have circumduction gait and those with cerebral palsy often have scissoring gait.

Tandem gait is a gait (method of walking or running) where the toes of the back foot touch the heel of the front foot at each step. Neurologists sometimes ask patients to walk in a straight line using tandem gait as a test to help diagnose ataxia, especially truncal ataxia, because sufferers of these disorders will have an unsteady gait. However, the results are not definitive, because many disorders or problems can cause unsteady gait (such as vision difficulties and problems with the motor neurons or associative cortex). Therefore, inability to walk correctly in tandem gait does not prove the presence of ataxia.

Profoundly affected tandem gait with no other perceptible deficits is a defining feature of posterior vermal split syndrome.

Suspects may also be asked to perform a tandem gait walk during the "walk and turn" part of a field sobriety test.

Gait abnormality is a deviation from normal walking (gait). Watching a patient walk is the most important part of the neurological examination. Normal gait requires that many systems, including strength, sensation and coordination, function in an integrated fashion. Many common problems in the nervous system and musculoskeletal system will show up in the way a person walks.

Subcortical arteriosclerotic encephalopathy (SAE), also called lower-body parkinsonism, and cerebellar ataxia are two other gait disorders whose symptoms seem to closely resemble that of Parkinson's. However, through regression analysis studies have revealed that in Parkinson's, increasing the velocity of walking changes the stride length linearly (which resembles that of controls). However, in SAE and cerebellar ataxia stride length had a disproportionate contribution to increasing velocity, indicating that SAE and cerebellar ataxia have common underlying mechanisms different from those of Parkinson's.

Myopathic gait (or waddling gait) is a form of gait abnormality.

The "waddling" is due to the weakness of the proximal muscles of the pelvic girdle.

The patient uses circumduction to compensate for gluteal weakness.

Conditions associated with a myopathic gait include pregnancy, congenital hip dysplasia, muscular dystrophies and spinal muscular atrophy

Bruns apraxia, or frontal ataxia is a gait apraxia found in patients with bilateral frontal lobe disorders. It is characterised by an inability to initiate the process of walking, despite the power and coordination of the legs being normal when tested in the seated or lying position. The gait is broad-based with short steps with a tendency to fall backwards. It was originally described in patients with frontal lobe tumours, but is now more commonly seen in patients with cerebrovascular disease.

It is named after Ludwig Bruns.

Toe walking refers to a condition where a person walks on their toes without putting much weight on the heel or any other part of the foot. Toe walking in toddlers is common. These children usually adopt a normal walking pattern as they grow older. If a child continues to walk on their toes past the age of three, they should be evaluated by a doctor.

Toe walking can be caused by different factors. One type of toe walking is also called "habitual" or "idiopathic" toe walking, where the cause is unknown. Other causes include a congenital short Achilles tendon, muscle spasticity (especially as associated with cerebral palsy) and paralytic muscle disease such as Duchenne muscular dystrophy. A congenital shortening of the Achilles tendon can be hereditary, can take place over time as the result of abnormal foot structure which shortens the tendon, or can shorten over time if its full length is not being used. Toe walking is sometimes caused by a bone block located at the ankle which prevents the antagonist movement, dorsiflexion. This cause is often associated with trauma or arthritis. It may also be one way of accommodating a separate condition, foot drop. Persistent toe walking in children has been identified as a potential early sign of autism.

Toe walking has been found to be more prevalent in males than females when tested with very large numbers of children. This study looked for family history of toe walking and the connection to children demonstrating ITW. 64.2% of the subjects with ITW were males showing a relationship between ITW and males. Of 348 subjects with positive family history of toe walking, about 60% had family history on the paternal side showing it may be genetically related to paternal genes. In 30-42% of idiopathic toe walkers, a family link has been observed.

Stomping gait (or sensory ataxia gait) is a form of gait abnormality.

Frontal lobe ataxia is often associated with damage to the frontopontocerebellar tract (Arnold's bundle) that connects the frontal lobe to the cerebellum. This pathway normally sends information from the cortical regions to the cerebellum, particularly information used to initiate planned movement.

Many neurologists describe frontal lobe ataxia as really an apraxia, in which voluntary control of initiating movement is greatly hindered, but normal movement is present when elicited involuntarily or reflexively. This indicates that cerebellar function is intact and that the presented symptoms of Bruns apraxia are due to damage located within frontal lobe regions and pathways leading from there to the cerebellum.

The Trendelenburg gait pattern (or gluteus medius lurch) is an abnormal gait (as with walking) caused by weakness of the abductor muscles of the lower limb, gluteus medius and gluteus minimus. People with a lesion of superior gluteal nerve have weakness of abducting the thigh at the hip.

This type of gait may also be seen in L5 radiculopathy and after poliomyelitis, but is then usually seen in combination with foot drop.

During the stance phase, the weakened abductor muscles allow the pelvis to tilt down on the opposite side. To compensate, the trunk lurches to the weakened side to attempt to maintain a level pelvis throughout the gait cycle. The pelvis sags on the opposite side of the lesioned superior gluteal nerve.

This gait is precipitated by strain to the gluteus maximus and gluteus minimus. Sufferers frequently complain that an overly strenuous session at the gym, particularly with glute-isolating equipment, result in this awkward gait, or worse.

This gait may be caused by cleidocranial dysostosis.

Biofeedback and physical therapy have been used in treatment.

When the hip abductor muscles (gluteus medius and minimus) are weak, the stabilizing effect of these muscles during gait is lost.

When standing on the right leg, if the left hip drops, it's a positive right Trendelenburg sign (the contralateral side drops because the ipsilateral hip abductors do not stabilize the pelvis to prevent the droop).

"When the patient walks, if he swings his body to the right to compensate for left hip drop, he will present with a compensated Trendelenburg gait; the patient exhibits an excessive lateral lean in which the thorax is thrust laterally to keep the center of gravity over the stance leg."

Although HSP is a progressive condition, the prognosis for individuals with HSP varies greatly. It primarily affects the legs although there can be some upperbody involvement in some individuals. Some cases are seriously disabling while others are less disabling and are compatible with a productive and full life. The majority of individuals with HSP have a normal life expectancy.

Studies have been performed to determine the source of the association between toe walking and cerebral palsy patients. One study suggests that the toe walking—sometimes called an equinus gait—associated with cerebral palsy presents with an abnormally short medial and lateral gastrocnemius and soleus—the primary muscles involved in plantarflexion. A separate study found that the gait could be a compensatory movement due to weakened plantarflexion muscles. The study performed clinical studies to determine that a greater plantarflexion force is required for normal heel-to-toe walking than for toe walking. Able bodied children were tasked to perform gaits at different levels of toe walking and the study discovered that their toe walking could not reduce the force to the levels that cerebral palsy patients indicated in their walk. This suggests that cerebral palsy in which an equinus gait is present may be due to abnormally weakened plantarflexion that can only manage toe walking.

Training of the feet, utilizing foot gymnastics and going barefoot on varying terrain, can facilitate the formation of arches during childhood, with a developed arch occurring for most by the age of four to six years. Ligament laxity is also among the factors known to be associated with flat feet. One medical study in India with a large sample size of children who had grown up wearing shoes and others going barefoot found that the longitudinal arches of the bare-footers were generally strongest and highest as a group, and that flat feet were less common in children who had grown up wearing sandals or slippers than among those who had worn closed-toe shoes. Focusing on the influence of footwear on the prevalence of pes planus, the cross-sectional study performed on children noted that wearing shoes throughout early childhood can be detrimental to the development of a normal or a high medial longitudinal arch. The vulnerability for flat foot among shoe-wearing children increases if the child has an associated ligament laxity condition. The results of the study suggest that children be encouraged to play barefooted on various surfaces of terrain and that slippers and sandals are less harmful compared to closed-toe shoes. It appeared that closed-toe shoes greatly inhibited the development of the arch of the foot more so than slippers or sandals. This conclusion may be a result of the notion that intrinsic muscle activity of the arch is required to prevent slippers and sandals from falling off the child’s foot.

Flat feet can also develop as an adult ("adult acquired flatfoot") due to injury, illness, unusual or prolonged stress to the foot, faulty biomechanics, or as part of the normal aging process. This is most common in women over 40 years of age. Known risk factors include obesity, hypertension and diabetes. Flat feet can also occur in pregnant women as a result of temporary changes, due to increased elastin (elasticity) during pregnancy. However, if developed by adulthood, flat feet generally remain flat permanently.

If a youth or adult appears flatfooted while standing in a full weight bearing position, but an arch appears when the person plantarflexes, or pulls the toes back with the rest of the foot flat on the floor, this condition is called flexible flatfoot. This is not a true collapsed arch, as the medial longitudinal arch is still present and the windlass mechanism still operates; this presentation is actually due to excessive pronation of the foot (rolling inwards), although the term 'flat foot' is still applicable as it is a somewhat generic term. Muscular training of the feet is helpful and will often result in increased arch height regardless of age.

An upper motor neuron lesion (also known as pyramidal insufficiency) occurs in the neural pathway above the anterior horn cell of the spinal cord or motor nuclei of the cranial nerves. Conversely, a lower motor neuron lesion affects nerve fibers traveling from the anterior horn of the spinal cord or the cranial motor nuclei to the relevant muscle(s).

Upper motor neuron lesions occur in the brain or the spinal cord as the result of stroke, multiple sclerosis, traumatic brain injury and cerebral palsy.

Foot drop is a gait abnormality in which the dropping of the forefoot happens due to weakness, irritation or damage to the common fibular nerve including the sciatic nerve, or paralysis of the muscles in the anterior portion of the lower leg. It is usually a symptom of a greater problem, not a disease in itself. Foot drop is characterized by inability or impaired ability to raise the toes or raise the foot from the ankle (dorsiflexion). Foot drop may be temporary or permanent, depending on the extent of muscle weakness or paralysis and it can occur in one or both feet. In walking, the raised leg is slightly bent at the knee to prevent the foot from dragging along the ground.

Foot drop can be caused by nerve damage alone or by muscle or spinal cord trauma, abnormal anatomy, toxins, or disease. Toxins include organophosphate compounds which have been used as pesticides and as chemical agents in warfare. The poison can lead to further damage to the body such as a neurodegenerative disorder called organophosphorus induced delayed polyneuropathy. This disorder causes loss of function of the motor and sensory neural pathways. In this case, foot drop could be the result of paralysis due to neurological dysfunction. Diseases that can cause foot drop include trauma to the posterolateral neck of fibula, stroke, amyotrophic lateral sclerosis, muscular dystrophy, poliomyelitis, Charcot Marie Tooth disease, multiple sclerosis, cerebral palsy, hereditary spastic paraplegia, Guillain–Barré syndrome, and Friedreich's ataxia. It may also occur as a result of hip replacement surgery or knee ligament reconstruction surgery.

The causes of foot drop, as for all causes of neurological lesions, should be approached using a localization-focused approach before etiologies are considered. Most of the time, foot drop is the result of neurological disorder; only rarely is the muscle diseased or nonfunctional. The source for the neurological impairment can be central (spinal cord or brain) or peripheral (nerves located connecting from the spinal cord to an end-site muscle or sensory receptor). Foot drop is rarely the result of a pathology involving the muscles or bones that make up the lower leg. The anterior tibialis is the muscle that picks up the foot. Although the anterior tibialis plays a major role in dorsiflexion, it is assisted by the fibularis tertius, extensor digitorum longus and the extensor halluces longus. If the drop foot is caused by neurological disorder all of these muscles could be affected because they are all innervated by the deep fibular (peroneal) nerve, which branches from the sciatic nerve. The sciatic nerve exits the lumbar plexus with its root arising from the fifth lumbar nerve space. Occasionally, spasticity in the muscles opposite the anterior tibialis, the gastrocnemius and soleus, exists in the presence of foot drop, making the pathology much more complex than foot drop. Isolated foot drop is usually a flaccid condition. There are gradations of weakness that can be seen with foot drop, as follows: 0=complete paralysis, 1=flicker of contraction, 2=contraction with gravity eliminated alone, 3=contraction against gravity alone, 4=contraction against gravity and some resistance, and 5=contraction against powerful resistance (normal power). Foot drop is different from foot slap, which is the audible slapping of the foot to the floor with each step that occurs when the foot first hits the floor on each step, although they often are concurrent.

Treated systematically, possible lesion sites causing foot drop include (going from peripheral to central):

1. Neuromuscular disease;

2. Peroneal nerve (common, i.e., frequent) —chemical, mechanical, disease;

3. Sciatic nerve—direct trauma, iatrogenic;

4. Lumbosacral plexus;

5. L5 nerve root (common, especially in association with pain in back radiating down leg);

6. Cauda equina syndrome, which is cause by impingement of the nerve roots within the spinal canal distal to the end of the spinal cord;

7. Spinal cord (rarely causes isolated foot drop) —poliomyelitis, tumor;

8. Brain (uncommon, but often overlooked) —stroke, TIA, tumor;

9. Genetic (as in Charcot-Marie-Tooth Disease and hereditary neuropathy with liability to pressure palsies);

10. Nonorganic causes.

If the L5 nerve root is involved, the most common cause is a herniated disc. Other causes of foot drop are diabetes (due to generalized peripheral neuropathy), trauma, motor neuron disease (MND), adverse reaction to a drug or alcohol, and multiple sclerosis.

HSP is a group of genetic disorders. It follows general inheritance rules and can be inherited in an autosomal dominant, autosomal recessive or X-linked recessive manner. The mode of inheritance involved has a direct impact on the chances of inheriting the disorder. Over 70 genotypes had been described, and over 50 genetic loci have been linked to this condition. Ten genes have been identified with autosomal dominant inheritance. One of these SPG4 accounts for ~50% of all genetically solved cases cases, or approximately 25% of all HSP cases. Twelve genes are known to be inherited in an autosomal recessive fashion. Collectively this latter group account for ~1/3 cases.

Most altered genes have known function, but for some the function haven’t been identified yet. All of them are listed in the gene list below, including their mode of inheritance. Some examples are spastin (SPG4) and paraplegin (SPG7) are both AAA ATPases.

An antalgic gait is a gait that develops as a way to avoid pain while walking ("" = "" + "", "against pain"). It is a form of gait abnormality where the stance phase of gait is abnormally shortened relative to the swing phase. It can be a good indication of pain with weight-bearing.

There are many hypotheses about how clubfoot develops. Some hypothesis include: environmental factors, genetics, or a combination of both. Research has not yet pinpointed the root cause, but many findings agree that "it is likely there is more than one different cause and at least in some cases the phenotype may occur as a result of a threshold effect of different factors acting together."

Some researchers hypothesize, from the early development stages of humans, that clubfoot is formed by a malfunction during gestation. Early amniocentesis (11–13 wks) is believed to increase the rate of clubfoot because there is an increase in potential amniotic leakage from the procedure. Underdevelopment of the bones and muscles of the embryonic foot may be another underlying cause. In the early 1900s it was thought that constriction of the foot by the uterus contributed to the occurrence of clubfoot.

Underdevelopment of the bones also affects the muscles and tissues of the foot. Abnormality in the connective tissue causes "the presence of increased fibrous tissue in muscles, fascia, ligaments and tendon sheaths".

These are the neural tracts which descend in the ventral horn of the spinal cord, carrying signals for voluntary movement of skeletal muscle. From their origin in the primary motor cortex, these nerves pass via the corona radiata to gather in the internal capsule before crossing over to the opposite side (decussation) in the medullary pyramids and proceeding down the spinal cord to meet lower motor neurons in the anterior grey column.

Bethlem myopathy is an autosomal dominant myopathy, classified as a congenital form of muscular dystrophy, that is caused by a mutation in one of the three genes coding for type VI collagen. These include COL6A1, COL6A2, and COL6A3.

Intention tremors are common among individuals with multiple sclerosis (MS). One common symptom of multiple sclerosis is ataxia, a lack of coordinated muscle movement caused by cerebellar lesions characteristic of multiple sclerosis. The disease often destroys physical and cognitive function of individuals.

Intention tremors can be a first sign of multiple sclerosis, since loss or deterioration of motor function and sensitivity are often one of the first symptoms of cerebellar lesions.

Intention tremors have a variety of other recorded causes as well. These include a variety of neurological disorders, such as stroke, alcoholism, alcohol withdrawal, peripheral neuropathy, Wilson's disease, Creutzfeldt–Jakob disease, Guillain–Barré syndrome and fragile X syndrome, as well as brain tumors, low blood sugar, hyperthyroidism, hypoparathyroidism, insulinoma, normal aging, and traumatic brain injury. Holmes tremor, a rubral or midbrain tremor, is another form of tremor that includes intention tremors, among other symptoms. This disease affects the proximal muscles of the head, shoulders, and neck. Tremors of this disease occur at frequencies of 2–4 Hz or more.

Intention tremor is also known to be associated with infections, West Nile virus, rubella, H. influenza, rabies, and varicella. A variety of poisons have been shown to cause intention tremor, including mercury, methyl bromide, and phosphine. In addition, vitamin deficiencies have been linked to intention tremor, especially deficiency in vitamin E. Pharmacological agents such as anti-arrhythmic drugs, anti-epileptic agents, benzodiazepine, cyclosporine, lithium, neuroleptics, and stimulants have been known to cause intention tremor. Some ordinary activities including ingesting too much caffeine, cigarettes, and alcohol, along with stress, anxiety, fear, anger and fatigue

have also been shown to cause intention tremor by negatively affecting the cerebellum, brainstem, or thalamus, as discussed in mechanisms.

Clubfoot is a birth defect where one or both feet are rotated inwards and downwards. The affected foot, calf, and leg may be smaller than the other. In about half of those affected, both feet are involved. Most cases are not associated with other problems. Without treatment, people walk on the sides of their feet which causes issues with walking.

The exact cause is usually unclear. A few cases are associated with distal arthrogryposis or myelomeningocele. If one identical twin is affected there is a 33% chance the other one will be as well. Diagnosis may occur at birth or before birth during an ultrasound exam.

Initial treatment is most often with the Ponseti method. This involves moving the foot into an improved position followed by casting, which is repeated at weekly intervals. Once the inward bending is improved, the Achilles tendon is often cut and braces are worn until the age of four. Initially the brace is worn nearly continuously and then just at night. In about 20% of cases further surgery is required.

Clubfoot occurs in about one in 1,000 newborns. The condition is less common among the Chinese and more common among Maori. Males are affected about twice as often as females. Treatment can be carried out by a range of healthcare providers and can generally be achieved in the developing world with few resources.