Water metabolism and postconcussional symptoms 5 weeks after mild head injury

Posttraumatic diabetes insipidus has been reported as a sequela to head injury. It is unknown whether subclinical types of diabetes insipidus, or other types of water metabolism disorders, occur after mild head injury (MHI) and, if so, whether they are related to the persistence of postconcussional symptoms. MHI patients (n = 38) were screened for disturbances of water metabolism by comparing plasma and urine osmolalities at about 5 weeks after the trauma. Eight patients had evidence of an increased plasma osmolality together with a relatively decreased urine osmolality after an overnight fast. The presence of this disturbance was significantly related to the persistence of postconcussional symptoms. The results suggest that subclinical disturbances of water metabolism may, among other factors, be related to the persistence of symptoms after MHI

Post-traumatic and emotional symptoms in different subgroups of patients with mild head injury

Post-concussional symptoms, such as headache, dizziness and irritability, are thought to result from the emotional stress associated with decreased cognitive performance after a head injury. A questionnaire-based investigation was carried out in 71 patients with mild head injury (MHI), using a heterogeneous item pool in order to study the interrelationships between traditional post-concussive complaints, cognitive problems, and more emotional and functional complaints. Factor analysis indicated that post-concussive symptoms loaded together with items on problems associated with decreased work performance and fatigability on a first factor, whereas psychovegetative and emotional complaints loaded together on a second factor. Two rating scales were constructed from the relevant items and were used to compare between subgroups of MHI patients and non-concussed controls. Patients with uncomplicated MHI had significantly higher scores than non-concussed subjects on the post-concussive-cognitive scale, but not on the emotional-vegetative scale. Patients with multiple head injuries or pre-existing emotional problems had higher scores on both the post-concussive-cognitive scale and the emotional-vegetative scale than MHI patients without a history of emotional problems. Reliable rating scales may be useful m multidiagnostic studies of MHI patients

Persistence of postconcussional symptoms in uncomplicated mildly head-injured patients: a prospective cohort study

We report the follow-up of 41 nonhospitalized subjects with uncomplicated mild head injury (MHI) and no premorbid compromising condition. At 3 months after the trauma 22 patients still complained of at least 1 postconcussional symptom (PCS) and 10 patients had 3 or more PCS. At 6 months 12 patients complained of at least 1 PCS, whereas 9 patients still had 3 symptoms or more. Patients with persistent PCS complained more of emotional symptoms. Results obtained with objective tests indicated that this group was characterized by a decreased performance on the Stroop Color Word Interference Test and a reduced tolerance to light and sound stimuli in comparison with patients with only few or no PCS. Persistent neurobehavioral deficits were correlated with scores on a postconcussive/cognitive rating scale, but not with scores on an emotional/vegetative scale. Although most patients may substantially recover after MHI, about 1 in 4 patients may persist with a residue of neurobehavioral deficits. Patients with persistent PCS should be evaluated in a multidiagnostic and objective way in order to gain a better understanding of the nature and origin of the subjective symptoms

Characteristics of oxygen isotope substitutions in the quasiparticle spectrum of Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}

There is an ongoing debate about the nature of the bosonic excitations responsible for the quasiparticle self energy in high temperature superconductors -- are they phonons or spin fluctuations? We present a careful analysis of the bosonic excitations as revealed by the `kink' feature at 70 meV in angle resolved photoemission data using Eliashberg theory for a d-wave superconductor. Starting from the assumption that nodal quasiparticles are not coupled to the $(\pi,\pi)$ magnetic resonance, the sharp structure at $70$meV can be assigned to phonons. We find that not only can we account for the shifts of the kink energy seen on oxygen isotope substitution but also get a quantitative estimate of the fraction of the area under the electron-boson spectral density which is due to phonons. We conclude that for optimally doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ phonons contribute $\sim 10$% and non-phononic excitations $\sim 90$%.Comment: 6 pages, 3 figure