Apolipoprotein E and functional recovery from brain injury following postacute rehabilitation.

OBJECTIVE: APOE epsilon4 has been associated with late-onset familial and sporadic AD and delayed recovery from head injury. The authors examined the relationship between functional recovery of patients with head injury and the APOE alleles. METHODS: Thirty-one patients with head injury who had completed the Acute Neurorehabilitation Program at Helen Hayes Hospital were evaluated for presence of APOE epsilon4 and assessed for recovery based on Functional Independence Measures (FIM). RESULTS: Analysis of covariance (using coma days as the covariate to control for differences in initial severity of injury between subjects with and without APOE epsilon4) revealed a significant difference for both total FIM and motor FIM scores between the subjects with and without APOE epsilon4. Specifically, there were lower scores for total FIM (df = 30; F = 3.341; p = 0.05) and motor FIM (df = 30; F = 4.189; p = 0.026) in APOE epsilon4 carriers. No difference was found for the cognitive portion of the FIM. CONCLUSIONS: The data suggest that the presence of the lipoprotein APOE epsilon4 adversely affects rehabilitation outcome for traumatic brain injury survivors.

Donepezil medicated memory improvement in traumatic brain injury during post acute rehabilitation.

Memory dysfunction is a recognized and difficult to treat complication of traumatic brain injury (TBI). Since medial-temporal lobe injury is a frequent contributor to memory dysfunction in TBI, it is likely that an acetylcholine deficit contributes to memory dysfunction in this population. Recently, Donepezil, an acetylcholine-esterase inhibitor which has demonstrated a high selectivity for neural Ach-esterase (with minimal side effects), was approved for use in dementia in Alzheimer's patients. Due to its promising results in Alzheimer's patients, and reports in the literature describing the use of physostigmine (an anti-cholinesterase with significant cardiovascular and autonomic side effects) to treat memory deficits in closed head injury, we decided to begin a trial of Donepezil in two patients with TBI who were experiencing long term static memory dysfunction refractory to conventional treatment. Both patients were admitted to our facility for physical and cognitive rehabilitation, and were started on a trial of Donepezil. Modified memory tests and subjective observations by both family and staff pointed to an improvement in memory within three weeks of starting Donepezil. Should these initial results be supported in larger trials, Donepezil may prove to be a valuable tool for the treatment of memory dysfunction in TBI.

Heart-rate variability in chronic traumatic brain injury.

Heart-rate variability (HRV), a measure of fluctuation around the mean heart rate, reflects the sympathetic and parasympathetic balance of the autonomic nervous system, and is an excellent technique to study cardiovascular tone in patients with neurological injuries. The purpose of this study was to determine whether abnormal HRV is present in patients with traumatic brain injury (TBI) during the post-acute recovery phase. Using a prospective, case/control design, we performed 24-h ambulatory ECG monitoring in seven TBI patients and in seven controls (C). There was a significant difference in root mean squared successive difference of RR intervals (C 40.4 +/- 10.3, TBI 23.3 +/- 16.5, p = 0.04) between TBI and C. Four patients with TBI (compared to one control) had abnormal standard deviation of the RR interval. When these four patients were compared to their matched controls, significant differences were found in frequency domain measure (In total power: TBI 4.4 +/- 0.9 ms2, C 7.1 +/- 1.4 ms2, In low frequency: TBI 3.3 +/- 1.1 ms2, C 6.4 +/- 1.4 ms2; In high frequency TBI 2.0 +/- 1.0 ms2, C 4.8 +/- 1.3 ms2, all p < 0.05). Thus, abnormalities in both time and frequency domains of HRV are present in TBI during the post-acute recovery phase.

Effect of a tracheostomy speaking valve on secretions, arterial oxygenation, and olfaction: a quantitative evaluation.

Tracheostomy speaking valves consist of a one-way valve that closes upon exhalation, causing a redirection of exhaled gas into the upper airway, thus allowing for the primary benefit of speech. The present study was undertaken to test various hypotheses concerning the secondary benefits of speaking valves. We hypothesized that use of a speaking valve will result in a decrease in accumulated secretions, an increase in arterial oxygenation and an improvement in olfactory function. A total of 8 tracheotomized patients met the following inclusion criteria: age > 18; ability to tolerate wearing a speaking valve for at least 3 hours; no unstable medical conditions; no use of thrombolytic agents. While using the speaking valve patients accumulated fewer secretions (74.3 +/- 63.6 vs. 122.8 +/- 44.6 ml/day, p = 0.004, n = 7) and had improved olfactory function (accuracy = 28.4 +/- 5.2 vs 8.1 +/- 2.9%, p = 0.02; and percent correct = 64.2 +/- 2.6 vs 50.0 +/- 3.9%, p = 0.03, n = 6) than when off the speaking valve. No significant differences were found in 24-hour arterial oxygen saturation (pulse oximetry and ABG analysis respectively, n = 7), arterial PO2, pH, PCO2, HCO3, or 24-hour heart rate (n = 7). Thus, the present study found a significant decrease in secretions and improvements in olfaction when tracheotomized patients wore a speaking valve, but no difference in arterial oxygenation.

Exertional hypotension in spinal cord injury.

STUDY OBJECTIVE: To assess blood pressure (BP) response to continuous maximal arm ergometry in patients with spinal cord injury (SCI). DESIGN: Cross-sectional analysis of data collected for a prospective study of functional electrical stimulation in patients with SCI. SETTING: Short-term rehabilitation hospital. PARTICIPANTS: Twenty individuals with SCI; 4 cervical (C6 to C8), 10 high thoracic (T1 to T6), and 6 low thoracic (T7 to T12). MEASUREMENTS AND RESULTS: Each subject performed continuous maximal arm ergometry with expired gas analysis. Blood pressure was measured using a technician-assisted protocol. The BP at maximal exercise was compared with the highest submaximal BP reached during the test (delta BP = final BP minus highest submaximal BP). All 20 subjects had a negative delta BP (mean +/- SD; -22.8 +/- 12.1 mm Hg) for mean BP and 19 of 20 had a negative delta BP (-25.8 +/- 14.4 mm Hg) for systolic BP. The delta BP was not significantly related to maximum exercise parameters, resting BP, or level of lesion. Four able-bodied subjects and six wheelchair-bound individuals without SCI showed no exertional hypotension. Repeated testing on the four able-bodied subjects showed excellent reproducibility for mean BP (coefficient of variation [CV] = 3.6 percent; r = 0.98; p < 0.01) and systolic BP (CV = 2.2 percent; r = 0.99; p < 0.01) using this protocol. CONCLUSIONS: These data describe, for the first time to our knowledge, that exertional hypotension is present in all individuals with SCI during continuous arm ergometry. Further studies are needed to clarify the mechanisms responsible for this phenomenon and to evaluate the long-term consequences for individuals with SCI.

Discrepancy between self-reported and actual caloric intake and exercise in obese subjects.

BACKGROUND AND METHODS: Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet--low total energy expenditure and underreporting of caloric intake--in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance. RESULTS: Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (+/- SD) of 47 +/- 16 percent and overreported their physical activity by 51 +/- 75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P < 0.05 as compared with group 2). CONCLUSIONS: The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis.