An Experimental Platform Generating Simulated Blunt Impacts to the Head Due to Rearward Falls

Impacts to the back of the head due to rearward falls, also referred to as "backfall" events, represent a common source of TBI for athletes and soldiers. A new experimental apparatus is described for replicating the linear and rotational kinematics of the head during backfall events. An anthropomorphic test device (ATD) with a head-borne sensor suite was configured to fall backwards from a standing height, inducing contact between the rear of the head and a ground surface simulant. A pivoting swing arm and release strap were used to generate consistent and realistic head kinematics. Backfall experiments were performed with the ATD fitted with an American football helmet and the resulting linear and rotational head kinematics, as well as calculated injury metrics, compared favorably with those of football players undergoing similar impacts during games or play reconstructions. This test method complements existing blunt impact helmet performance experiments, such as drop tower and pneumatic ram test methods, which may not be able to fully reproduce head-neck-torso kinematics during a backfall event.

High Energy Side and Rear American Football Head Impacts Cause Obvious Performance Decrement on Video

The objective of this study was to compare head impact data acquired with an impact monitoring mouthguard (IMM) to the video-observed behavior of athletes' post-collision relative to their pre-collision behaviors. A total of n = 83 college and high school American football players wore the IMM and were video-recorded over 260 athlete-exposures. Ex-athletes and clinicians reviewed the video in a two-step process and categorized abnormal post-collision behaviors according to previously published Obvious Performance Decrement (OPD) definitions. Engineers qualitatively reviewed datasets to check head impact and non-head impact signal frequency and magnitude. The ex-athlete reviewers identified 2305 head impacts and 16 potential OPD impacts, 13 of which were separately categorized as Likely-OPD impacts by the clinical reviewers. All 13 Likely-OPD impacts were in the top 1% of impacts measured by the IMM (ranges 40-100 g, 3.3-7.0 m/s and 35-118 J) and 12 of the 13 impacts (92%) were to the side or rear of the head. These findings require confirmation in a larger data set before proposing any type of OPD impact magnitude or direction threshold exists. However, OPD cases in this study compare favorably with previously published impact monitoring studies in high school and college American football players that looked for OPD signs, impact magnitude and direction. Our OPD findings also compare well with NFL reconstruction studies for ranges of concussion and sub-concussive impact magnitudes in side/rear collisions, as well as prior theory, analytical models and empirical research that suggest a directional sensitivity to brain injury exists for single high-energy impacts.

Laboratory and On-field Data Collected by a Head Impact Monitoring Mouthguard

Although concussion continues to be a major source of acute and chronic injury in automotive, athletic and military arenas, concussion injury mechanisms and risk functions are ill-defined. This lack of definition has hindered efforts to develop standardized concussion monitoring, safety testing and protective countermeasures. Recent research has provided evidence of the role of repetitive head impact exposure as a predisposing factor for the onset of concussion using developed instrumented helmets and mouthguards.To overcome this knowledge gap, we have developed, tested and deployed a head impact monitoring mouthguard (IMM) system. In this study, we deployed the IMM system to gather high quality estimates of athlete head impacts in situ. And with enough longer-term data collection, potential concussive events or mild traumatic brain injuries (mTBIs) will be gathered and ideally will provide actionable risk-based threshold.

Development of a head impact monitoring "Intelligent Mouthguard"

The authors present the development and laboratory system-level testing of an impact monitoring "Intelligent Mouthguard" intended to help with identification of potentially concussive head impacts and cumulative head impact dosage. The goal of Intelligent Mouthguard is to provide an indicator of potential concussion risk, and help caregiver identify athletes needing sideline concussion protocol testing. Intelligent Mouthguard may also help identify individuals who are at higher risk based on historical dosage. Intelligent Mouthguard integrates inertial sensors to provide 3-degree of freedom linear and rotational kinematics. The electronics are fully integrated into a custom mouthguard that couples tightly to the upper teeth. The combination of tight coupling and highly accurate sensor data means the Intelligent Mouthguard meets the National Football League (NFL) Level I validity specification based on laboratory system-level test data presented in this study.

Responses of the Human Brain to Mild Dehydration and Rehydration Explored In Vivo by 1H-MR Imaging and Spectroscopy

BACKGROUND AND PURPOSE

As yet, there are no in vivo data on tissue water changes and associated morphometric changes involved in the osmo-adaptation of normal brains. Our aim was to evaluate osmoadaptive responses of the healthy human brain to osmotic challenges of de- and rehydration by serial measurements of brain volume, tissue fluid, and metabolites.

MATERIALS AND METHODS

Serial T1-weighted and (1)H-MR spectroscopy data were acquired in 15 healthy individuals at normohydration, on 12 hours of dehydration, and during 1 hour of oral rehydration. Osmotic challenges were monitored by serum measures, including osmolality and hematocrit. MR imaging data were analyzed by using FreeSurfer and LCModel.

RESULTS

On dehydration, serum osmolality increased by 0.67% and brain tissue fluid decreased by 1.63%, on average. MR imaging morphometry demonstrated corresponding decreases of cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus. These changes reversed during rehydration. Continuous fluid ingestion of 1 L of water for 1 hour within the scanner lowered serum osmolality by 0.96% and increased brain tissue fluid by 0.43%, on average. Concomitantly, cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus increased. Changes in brain tissue fluid were related to volume changes of the whole brain, the white matter, and hypothalamus/thalamus. Only volume changes of the hypothalamus/thalamus significantly correlated with serum osmolality.

CONCLUSIONS

This is the first study simultaneously evaluating changes in brain tissue fluid, metabolites, volume, and cortical thickness. Our results reflect cellular volume regulatory mechanisms at a macroscopic level and emphasize that it is essential to control for hydration levels in studies on brain morphometry and metabolism in order to avoid confounding the findings.

Biomechanical analysis of the upper thoracic spine after decompressive procedures

BACKGROUND CONTEXT

Decompressive procedures such as laminectomy, facetectomy, and costotransversectomy are routinely performed for various pathologies in the thoracic spine. The thoracic spine is unique, in part, because of the sternocostovertebral articulations that provide additional strength to the region relative to the cervical and lumbar spines. During decompressive surgeries, stability is compromised at a presently unknown point.

PURPOSE

To evaluate thoracic spinal stability after common surgical decompressive procedures in thoracic spines with intact sternocostovertebral articulations.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Fresh-frozen human cadaveric spine specimens with intact rib cages, C7-L1 (n=9), were used. An industrial robot tested all spines in axial rotation (AR), lateral bending (LB), and flexion-extension (FE) by applying pure moments (±5 Nm). The specimens were first tested in their intact state and then tested after each of the following sequential surgical decompressive procedures at T4-T5 consisting of laminectomy; unilateral facetectomy; unilateral costotransversectomy, and subsequently instrumented fusion from T3-T7.

RESULTS

We found that in all three planes of motion, the sequential decompressive procedures caused no statistically significant change in motion between T3-T7 or T1-T12 when compared with intact. In comparing between intact and instrumented specimens, our study found that instrumentation reduced global range of motion (ROM) between T1-T12 by 16.3% (p=.001), 12% (p=.002), and 18.4% (p=.0004) for AR, FE, and LB, respectively. Age showed a negative correlation with motion in FE (r = -0.78, p=.01) and AR (r=-0.7, p=.04).

CONCLUSIONS

Thoracic spine stability was not significantly affected by sequential decompressive procedures in thoracic segments at the level of the true ribs in all three planes of motion in intact thoracic specimens. Age appeared to negatively correlate with ROM of the specimen. Our study suggests that thoracic spinal stability is maintained immediately after unilateral decompression at the level of the true ribs. These preliminary observations, however, do not depict the long-term sequelae of such procedures and warrant further investigation.

Boxing and mixed martial arts: preliminary traumatic neuromechanical injury risk analyses from laboratory impact dosage data

Object

In spite of ample literature pointing to rotational and combined impact dosage being key contributors to head and neck injury, boxing and mixed martial arts (MMA) padding is still designed to primarily reduce cranium linear acceleration. The objects of this study were to quantify preliminary linear and rotational head impact dosage for selected boxing and MMA padding in response to hook punches; compute theoretical skull, brain, and neck injury risk metrics; and statistically compare the protective effect of various glove and head padding conditions.

Methods

An instrumented Hybrid III 50th percentile anthropomorphic test device (ATD) was struck in 54 pendulum impacts replicating hook punches at low (27–29 J) and high (54–58 J) energy. Five padding combinations were examined: unpadded (control), MMA glove–unpadded head, boxing glove–unpadded head, unpadded pendulum–boxing headgear, and boxing glove–boxing headgear. A total of 17 injury risk parameters were measured or calculated.

Results

All padding conditions reduced linear impact dosage. Other parameters significantly decreased, significantly increased, or were unaffected depending on padding condition. Of real-world conditions (MMA glove–bare head, boxing glove–bare head, and boxing glove–headgear), the boxing glove–headgear condition showed the most meaningful reduction in most of the parameters. In equivalent impacts, the MMA glove–bare head condition induced higher rotational dosage than the boxing glove–bare head condition. Finite element analysis indicated a risk of brain strain injury in spite of significant reduction of linear impact dosage.

Conclusions

In the replicated hook punch impacts, all padding conditions reduced linear but not rotational impact dosage. Head and neck dosage theoretically accumulates fastest in MMA and boxing bouts without use of protective headgear. The boxing glove–headgear condition provided the best overall reduction in impact dosage. More work is needed to develop improved protective padding to minimize linear and rotational impact dosage and develop next-generation standards for head and neck injury risk.

Magic angle effect: a relevant artifact in MR neurography at 3T?

BACKGROUND AND PURPOSE

MRN is an emerging diagnostic method for disorders of peripheral nerves. However, it is unclear whether the influence of the MA on intraneural T2 signal is severe enough to provoke false-positive findings.

MATERIALS AND METHODS

Twenty-five healthy subjects underwent MRN of the sciatic nerve of the proximal thigh at 3T. The T2(app) was calculated from a DE-TSE sequence (TR = 3000 ms, TE1 = 12 ms, TE2 = 69 ms) at 7 angles of the sciatic nerve relative to B0 = 0°, 30°, 35°, 40°, 45°, 50°, and 55°. Precise angle adjustments were performed with a dedicated in-bore positioning aid. Qualitative evaluation of intraneural T2-weighted contrast between this group of healthy subjects and 14 patients with neuropathic lesions was performed by comparing CNRs of a TIRM sequence (TR = 5000 ms, TE = 76 ms, TI = 180 ms).

RESULTS

In healthy subjects, the prolongation of T2(app) from 0° to 55° was from 74.5 ± 13.4 to 104.0 ± 16.9 ms (P < .001). The increase in T2(app) relative to baseline (0°) was 9.6% (30°), 18.4% (35°), 25% (40°), 27.6% (45°), and 37% (55°). Intraneural CNR increased by 1.98 ± 0.69 at 40° and 2.93 ± 0.46 at 55°. Nevertheless, the mean CNR of healthy subjects was substantially lower than that in patients at 40° (P < .0001) and even at the position of maximum MA (55°: 20.6 ± 5.11 versus 52.6 ± 7.12, P < .0001).

CONCLUSIONS

Neuropathic lesions are clearly distinguishable from an artificial increase of intraneural T2 by the MA. Even at a maximum MA (55°), the false-positive determination of a neuropathic lesion is unlikely.

Minor crashes and 'whiplash' in the United States

In the United States there is currently a paucity of available real world minor rear crash data with struck vehicle delta-V, or speed change, less than or equal to 15 kilometers per hour. These data are essential as researchers attempt to define 'whiplash' injury risk potential in these minor crashes. This study analyzed a new set of 105 U.S. minor rear aligned crashes between passenger vehicles. Mean struck vehicle delta-V and acceleration were 6.3 km/h (s.d. = 2.1 km/h) and 1.4 g (s.d. = 0.5 g), respectively. A total of 113 struck vehicle occupants were diagnosed within five weeks post-crash with 761 ICD-9-CM complaints and 427 AIS injuries (99.5% AIS1) attributed to the crashes. No striking vehicle occupants reported complaints. The main ICD-9-CM diagnoses were 40.6% cervical, 22.5% lumbar/sacral and 10.2% thoracic and the main AIS1 diagnoses were 29.7% cervical, 23.2% lumbar/sacral and 14.3% thoracic. The diagnosis disparity was mainly due to coding for pre-existing degenerative diagnosis in ICD-9-CM. Degenerative spine conditions were not significant for increased AIS1 injury risk. Surprisingly, many non-'whiplash' diagnoses were found. The AIS injury diagnosis distribution and frequency in these minor delta-V crashes did not correspond with previous minor rear crash studies. A prospectively collected and unbiased minor rear crash databank in the model of CIREN or NASS is highly desirable to verify or refute these results for the U.S. population since the current study cohort may have been influenced by litigation.

CT perfusion predicts secondary cerebral infarction after aneurysmal subarachnoid hemorrhage

OBJECTIVE

To prospectively assess the diagnostic accuracy of CT perfusion (CTP) and transcranial Doppler sonography (TCD) for the prediction of secondary cerebral infarction (SCI) after aneurysmal subarachnoid hemorrhage (SAH).

METHODS

During 2 weeks after SAH, 38 consecutive patients completed an average of 3.5 CT/CTP and 10.7 TCD examinations at regular intervals as required by the study protocol. SCI was defined as delayed infarction on native CT between 3 and 14 days after SAH and developed in n = 14 patients (n = 24 without SCI). Analysis was based on examination dates before SCI. Common measures of diagnostic accuracy were calculated for qualitative CTP (visual color-map ratings from two blinded observers) and TCD assessments (mean flow velocity >120 cm/s in anterior, middle, and posterior cerebral artery territories). Quantitative measures, which for CTP were obtained from cortical a priori regions of interest corresponding to the vascular territories, were analyzed by binary logistic regression.

RESULTS

Time of prediction for SCI by CTP was at a median of 3 days (range 2 to 5 days) before manifestation of complete infarction on native CT. Visual assessment of time-to-peak (TTP) color maps performed best for the prediction of SCI with 0.93 sensitivity (95% CI: 0.7 to 1.0) and 0.67 specificity (95% CI: 0.53 to 0.7). On quantitative analysis, the odds ratio (OR) for 1 second of side-to-side delay in TTP was 1.4 (p = 0.01, Wald chi(2) = 8.57, CI: 1.07 to 1.82). Daily TCD measures were not significantly related to SCI at any time before complete infarction on native CT.

CONCLUSIONS

Time to peak as indicated by CT perfusion is a sensitive and early predictor of secondary cerebral infarction.

Cycloid psychoses -- from clinical concepts to biological foundations

The modern concept of cycloid psychoses is primarily based upon the clinical delineation of their phenotypes according to Leonhard. By settling the dilemma of Kraepelinean "atypical psychoses", their description may be considered one of the major achievements of clinical psychiatry in the last century. In particular, this had been facilitated by the work of Wernicke and Kleist. Albeit not yet generally recognized, cycloid psychoses have already stimulated great efforts of research yielding remarkable results. In this article, we elucidate the concept of cycloid psychoses and present recent findings pertaining to their putative biological foundations. Finally, future perspectives for the field of biological psychiatry are proposed fostering the heuristics of Leonhard's nosology.

Electrophysiological measurements of anterior cingulate function

Based on recent findings from various areas of brain research the anterior cingulate cortex (ACC) within the prefrontal cortex is increasingly considered as a brain region activated during tasks requiring conflict-monitoring and allocation of attention. In the present study with event-related potentials (ERPs) the question has been addressed, whether the NoGo-condition of the Continuous Performance Test is associated with enough conflict-monitoring and allocation of attention in order to activate the ACC in healthy controls. Low Resolution Electromagnetic Tomography (LORETA), a new three-dimensional source localization method, revealed significantly increased brain electrical activity during the NoGo-ERP as compared to the Go-ERP with its maximum located exactly within the ACC in four independent samples of healthy subjects. These results relate the conflict-monitoring requirements associated with inhibition of a prepared motor response (NoGo-condition) to a powerful brain electrical ACC-activity. This non-invasive, easy to perform and inexpensive electrophysiological measurement, therefore, provides a new method for the assessment of ACC-function in healthy subjects.

Differences in substantia nigra echogenicity of nosological subtypes within the schizophrenic spectrum. A preliminary transcranial ultrasound study

OBJECTIVE

Schizophrenic patients treated with neuroleptic drugs often develop neuroleptic-induced parkinsonism (NIP). Here, transcranial sonography (TCS) was used to test for differences in the susceptibility to NIP related to the echogenicity of the substantia nigra (SN) in different schizophrenic subforms.

METHODS

79 patients with schizophrenic spectrum psychoses treated by neuroleptic drugs and diagnosed according to ICD-10 and Leonhard's nosology were examined independently by TCS and, clinically, for NIP.

RESULTS

Patients with larger echogenic SN had more severe NIP (p < 0.05). Diagnostic categories according to ICD-10 did not differ significantly in SN echogenicity (p > 0.2), whereas Leonhard's did (p < 0.05).

CONCLUSIONS

These findings suggest altered SN echogenicity in subtypes of the schizophrenic spectrum. The putative role of the nigrostriatal system in the etiology of schizophrenic subtypes is discussed.

Long-term reliability of electrophysiologic response control parameters

The execution (Go) and the inhibition (NoGo) of a motor response are basic cognitive processes that can be assessed by means of a simple neuropsychological Go-NoGo task: the Continuous Performance Test (CPT). Simultaneous electrophysiologic investigations revealed that the NoGo condition of the CPT is associated with a clearly more anterior brain electrical activity compared with the Go condition. Recently, it has been shown that this NoGo anteriorization effect during a response control paradigm can be measured quantitatively with the electrophysiologic centroid method. The objective of the current study, therefore, was to determine the long-term reliability of the topographic measures of cognitive response control (i.e., location of the Go and the NoGo centroid and the NoGo anteriorization). For this purpose, a 21-channel EEG was recorded twice from 13 healthy volunteers during their execution of a cued CPT (O-X version). The time interval between test and retest was 2.74 years (range, 2.41 to 2.97 years). Statistical analysis of the event-related Go and NoGo potentials revealed an excellent test-retest reliability, as expressed by Pearson's product moment correlation coefficients of more than 0.85 (P < or = 0.0005) and intraclass correlation coefficients of more than 0.90 (P </= 0.0005) for all three topographic measures. These results indicate that these electrophysiologic parameters present with superior long-term reliability and that they may be applied as electrophysiologic trait markers of response control mechanisms in the human brain.

Sequential MRI and MR spectroscopy in embolized meningiomas: correlation with surgical and histopathological findings

The preoperative embolization of meningiomas is commonly used to facilitate surgery. The purpose of this study was to evaluate the morphological and metabolic changes in embolized meningiomas and to correlate the results with surgical and histopathological findings. In a prospective study, 36 patients with intracranial meningiomas were included. The extent of devascularization was assessed by angiography and MR volumetry. MRI and MR spectroscopy (MRS) were performed before and sequentially after embolization. At surgery, blood loss was measured and intraoperative duplex-mode ultrasound was applied to identify avascular tumor portions. Histopathological specimens were evaluated for the histological subtype, localization and extent of necrotic tumor portions. Postembolization MRI revealed a variable pattern of secondary revascularization and devascularization with an early onset following embolization. In all patients, peripheral secondary enhancement was present which histopathologically represented a thin layer of vital tumor tissue. MRS revealed lactate in devascularized areas immediately after embolization. Lipids were not observed before the 3rd day after embolization and were always associated with avascular and soft tissue at the time of surgery. Embolized meningiomas feature a variable dynamic with the potential for revascularization and secondary devascularization. Lipid signals indicate avascular and soft tissue at surgery. In case of delayed surgery, MRI and MRS should be performed in order to exclude revascularization and to establish the fatty degeneration of the meningioma.

Sequential MR imaging and proton MR spectroscopy in patients who underwent recent detoxification for chronic alcoholism: correlation with clinical and neuropsychological data

BACKGROUND AND PURPOSE

Chronic alcohol abuse may cause neuropsychological disorders and result in brain atrophy. The purpose of this study was to evaluate the metabolic, morphologic, and functional cerebral changes in the early stage of abstinence from chronic alcoholism.

METHODS

Seventeen alcohol-dependent patients underwent MR imaging and MR spectroscopy on days 1 through 3 and days 36 through 39 of abstinence. In addition, psychological performance measures testing intelligence, concentration, attention, and memory were applied. Neuropsychological data were correlated with spectroscopic and volumetric results by using a Pearson's product moment correlation. The same measurements were also performed in 12 healthy, age-matched control subjects. Peak integral values for N-acetylaspartate (NAA) and choline (Cho) were referred to the peak integral value of creatine (Cr) as the internal reference.

RESULTS

NAA/Cr was decreased in the patients in both the frontal lobes and cerebellum immediately after cessation of drinking (days 1 through 3). After 36 to 39 days of abstinence, NAA/Cr had significantly increased in the patients and corresponded to performance on psychological tests. The Cho/Cr ratio was decreased in the cerebellum during early abstinence but was recovered on days 36 through 39. The patients had enlarged CSF spaces 1 to 3 days after detoxification, which decreased during sobriety. The extent of brain atrophy did not correspond to performance on psychological performance tests.

CONCLUSION

Regression of brain atrophy and metabolic recovery occurs at an early stage after abstinence from chronic alcohol abuse. MR spectroscopy findings return to normal metabolic levels within weeks after detoxification. The recovery of NAA/Cr is associated with improved performance on neuropsychological tests.

Test-retest reliability of electrophysiological parameters related to cognitive motor control

Previously, the continuous performance test was demonstrated to elicit distinct electrophysiological correlates of cognitive response during execution (Go) and inhibition (NoGo) of an anticipated motor response. A robust method for topographical quantification of these brain electrical microstates has been established recently. Test reliability is crucial to allow application in the assessment of neuropsychiatric disorders. The present study evaluates the reliability of the Go and NoGo centroid locations as well as the NoGo anteriorisation (NGA) in 23 healthy individuals. Our results show supreme test-alternate retest reliabilities of Pearson's product moment correlations and intraclass correlation coefficients of r> or =0.63 (P< or =0.001) for these parameters which assert a quality well within the range reported for those of other electrophysiological standard paradigms. Go and NoGo centroid locations as well as the NGA are, therefore, reliable correlates of prefrontal motor control and may contribute to the understanding of disorders with allied impairments.

[Hypochondriacal euphoria as a special form of monopolar affective psychosis]

BACKGROUND

In contemporary concepts of affective psychoses the existence of monopolar manias is widely questioned. Nevertheless, cases of manias with monomorphous symptomatology are reported repeatedly from all over the world. Based upon subtle observation of signs and course over many years, Karl Leonhard developed a concept of affective psychoses that permits a distinction of monopolar from bipolar forms, e.g. monopolar manias and euphoric euphorias.

METHODS

As an example for the pure forms of euphorias we present two cases of hypochondriacal euphoria.

CONCLUSION

We discuss some of the literature relevant to the issue and propose the application of a differentiated psychopathological analysis for the discrimination of monopolar from bipolar manias.

[Reliability of electrophysiological measurements of motor control]

OBJECTIVES

The aim of the study was the short term test-retest-reliability of electrophyisiological correlates of simple processes of the motor control, i.e. the execution (go) and the inhibition (no go) of a prepared motor response, evoked during the Continuous Performance Test (CPT). Our interest was centered in the reliability of the topographical P300-parameters described in previous studies, i.e. the localizations of the go and no go centroids and the no go anteriorization (NGA), which is the difference between the two centroid locations. A sufficient reliability is a basic requirement for the application of these new topographical parameters for the investigation of different psychiatric illnesses with suspected dysfunctions of prefrontal motor control, e.g. schizophrenias and affective illnesses, obsessive-compulsive disorders, personality disorders with deficits in impulse control, and in children with attention deficit hyperactivity disorder.

PATIENTS AND METHODS

We examined 23 healthy subjects who executed two versions of the CPT with an interval of 30 minutes. After averaging the obtained evoked potentials of each subject, we determined the latencies, amplitudes and positive centroids, at the moment of the peak of the Global Field Power in a P300 time window.

RESULTS

Statistical analysis revealed sufficient test-retest-reliabilities in comparison to other electrophysiological paradigms, mainly for the localizations of the go (r = 0.93; p = 10(-10)) and no go centroid (r = 0.85; p = 10(-4)), as well as for the no go anteriorization (r = 0.63; p = 10(-3)).

CONCLUSION

These results are a prerequisite for the application of these topographical parameters as measures of the prefrontal motor control in different healthy and psychiatric populations.

[Anorexia nervosa--the triad of metric index, BMI age-specific percentile curve and goal weight]

Cross sectional and longitudinal data from the Berlin Anorexia Study on the inpatient treatment of n = 133 adolescent females with the principal axis I diagnosis of an eating disorder (n = 104 anorexia nervosa, n = 19 bulimia nervosa, n = 10 eating disorders not otherwise specified; according to ICD-10 and DSM-IV criteria) indicate a significant shift in the frequency distribution of somatometrically assessed types of body shape among patients as categorized by the Metric Index, towards the leptomorphic phenotype (p < 0.050, chi 2/Fisher's). Three explanatory models are discussed. Diagnostic and therapeutic implications, particularly of the determination of target weight in anorexia nervosa based on the individual's type of body shape, are emphasized, and an operational algorithm is proposed which uses the Metric Index and sex-specific BMI age percentiles adjusted for type of body shape.

[Anorexia nervosa and "anorexia athletica"]

Available evidence supports the assumption that stressors in vulnerable adolescence potentially lead to restrictive dieting and imbalances of serotonergic metabolic particularly in females. In conjunction with idealized body images and developmentally characteristic bodily perceptions prone to distortion pathogenetic mechanisms of eating disorders are released. The entities of eating disorders are dimensionally viewed as points of continua a functions and categorized according to ICD-10 or DSM-IV, respectively. Data of our studies on grammar school students, ballet dancers and anorexia nervosa patients emphasize the necessity to differentiate different types of body shape by using the metric index. Facing this background a distinction of "anorexia athletica" appears unreasonable.