Gait Disturbance
Gait disturbance is the principle symptom of NPH and often among the earliest to manifest.[3] When gait disturbance precedes mental deterioration, a more favorable outcome is expected than when it does not.[12,14,15] Individuals with NPH may have difficulty initiating gait or transfers.[20] Typically, length of stride and height of steps are reduced.[33] Eventually, a shuffling, broad-based gait interferes with ambulation.[20]
Disturbances in gait are addressed by the physical therapist. The therapy consists of activities aimed at increasing strength and balance and at improving the quality and safety of gait. An assistive device, family training, and review of the home environment may be needed for any adjustments that will maximize the patient's safety and independence. Many of the therapeutic principles applied to this population are gleaned from geriatric, fall risk, and Parkinson's literature.
Urinary Incontinence During the early stages of NPH, urinary incontinence is often reported in patients.[3,19] It can also occur during the latter stages.[13] Typically, urinary incontinence and self-care skills are addressed by nursing and the occupational therapist. Initially, incontinence may be related to an individual's decline in mobility, but it may become multifactorial associated with a decline in cognition, infection, or other medical factors such as prostate disease. Nursing establishes a toileting program, and the family and treatment team help to ensure regular toileting times to promote continence. The occupational therapist evaluates the patient's need for adaptive equipment to improve independence and to reduce the burden on caregivers.
Cognitive Decline
The cognitive changes associated with NPH vary from day to day and from patient to patient. The neuropsychologist evaluates the patient's cognitive and emotional status and consults with the rehabilitation staff. Information obtained from the neuropsychological evaluation is used by speech therapists to help focus cognitive interventions and compensatory strategies. Recommendations and compensatory techniques also are provided to families and caregivers.
Cognitive decline may involve disorientation, confusion, apathy, decreased attention span, reduced speed of information processing, and motor slowing while many cognitive functions, judgment, and self-awareness are preserved relatively well.[20] Unlike primary degenerative disorders such as the dementias (e.g., Alzheimer's disease), if correctly diagnosed, the deteriorating process of NPH may be reversible by surgical placement of a ventricular shunt. If NPH is left to run its course, however, progressive mental debilitation will occur. In its later stages, NPH resembles primary dementias.[20]
During the early stages of NPH, motor slowing,impaired attention,and difficulties in mental tracking are common.[24] Memory difficulties may be apparent in the early stages although such difficulties can be related to confusion and attention deficits rather than to a primary registration deficit or learning disability. In the initial stages, emotional and psychiatric symptoms, such as agitation, anxiety, depression, and paranoidal delusion,may emerge.[20,31] As the condition worsens,the memory system unequivocally becomes affected. Typically, learning and recall of both visual and verbal material are compromised although episodic memory remains intact.24 Deficits associated with frontal lobe dysfunction, including verbal fluency, cognitive flexibility, and attention, also are common.[17]
Outcome Research
Most research on outcomes after NPH has focused on the effectiveness of shunt placement. Surgery substantially improves gait disturbance,[11,21,25] incontinence,[25] and cognitive impairment. [2,5,6,16,18,22,28] For example, Larsson and colleagues[19] reported improvements in length of step and a decrease of arrestments and gait ataxia as long as 1 year after shunt surgery. Urinary incontinence has improved as soon as 1 week after placement of a shunt.[25] Postoperative improvements have been reported in memory, reaction time, visuospatial functions, wakefulness, and initiative.[10,15,16,19,21,25,30,34] Psychiatric symptoms also have improved after surgery.[26] However,deficits associated with frontal lobe dysfunction, such as attention and cognitive flexibility, have improved little after shunting.[4,8,16,17,31,34,35]
Several factors contribute to improvements after surgery. For example, a brief history of the disorder and a known cause are both important prognostic factors.[2,16,22,37] Compared to the idiopathic form, NPH caused by subarachnoid hemorrhage has been associated with better outcomes.[2,16,32] Similarly, 60% to 75% of patients with secondary NPH[9,34,36] showed improvement compared with 10 to 53% of patients with idiopathic NPH.[5-7,34,36] Other investigators have found no prognostic relevance associated with etiology.[37] Thomsen and colleagues[34] reported improved cognitive function in 80% of patients 1 year after surgery when three or more of the following signs were present: known cause, brief history, low cerebrospinal fluid outflow, small sulci, or periventricular hypodensity on computed tomography.
Although several studies have documented improvements in symptoms after surgical placement of a shunt, none of these studies have examined outcomes after rehabilitation. Yet, many patients undergo intensive therapy in a rehabilitation setting after surgery to help improve gait disturbance, incontinence, and cognitive impairment. Many of the therapeutic interventions used with the NPH population are based on treatment known to be effective for patients with different diagnoses but similar functional and cognitive deficits. Whether early rehabilitation interventions can help improve functioning and facilitate recovery after surgical treatment for NPH has yet to be determined.
Conclusion
Inpatient neurorehabilitation is often warranted for patients with NPH during the early stages of recovery from shunt surgery. Overall clinical improvement after surgical placement of a ventricular shunt has been reported.[23,27,29] However, the efficacy of specific therapeutic interventions used during early rehabilitation has not yet been studied systematically and empirically. Research is needed to document the outcomes associated with the therapeutic interventions used by the multidisciplinary rehabilitation team to treat patients with NPH.
